Schneider Electric TAC I/A Series Operating Instructions

Download

TAC I/A Series MicroNet BACnet

Wiring, Networking, and

Best Practices Guide

TAC I/A Series MicroNet BACnet

Wiring, Networking, and

Best Practices Guide

Printed in U.S.A. 06-14 F-27360-11

Distributed, manufactured, and sold by Schneider Electric. I/A Series trademarks are owned by Invensys Systems, Inc. and are used on this product under master license from Invensys. Invensys does not manufacture this product or provide any product warran ty or support. For service, support, and warranty information, contact Schneider Electric.

All brand names, trademarks and registered trademarks are the property of th eir respective owners. Information contained within this document is subj ect to change without notice.

Schneider Electric

F-27360-11 June 2014 tl

Preface

Purpose of this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Applicable Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Related Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Conventions Used in this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii

Acrobat (PDF) Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii

Abbreviations and Terms Used in this Manual . . . . . . . . . . . . . . .xii

Manual Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii

Chapter 1 I/A Series BACnet Hardware

MicroNet BACnet Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Common Controller Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

BACnet Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

MNB-300 Unitary Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

MNB-V1, MNB-V2 VAV Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . 5

MNB-70 Zone Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

MNB-1000 Plant Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

MNB-1000-15 Remote I/O Module . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Input and Output Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Universal Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Universal Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Digital Outputs, Triac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

20 Vdc Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Inputs from MN-Sx MicroNet Sensor . . . . . . . . . . . . . . . . . . . . . . 19

Velocity Pressure Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

MicroNet Digital Wall Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Common Sensor Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Keypad Icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

LCD Icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Diagnostic Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Communications Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Intermixing of Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide iii

Table of Contents

Chapter 2 Networking Practices

Sensor Link (S-Link) Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

MicroNet MS/TP Network Wiring . . . . . . . . . . . . . . . . . . . . . . . . . 26

ADI and Remote I/O Network Wiring . . . . . . . . . . . . . . . . . . . . . . 27

I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Power Supply Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Sensor Link (S-Link) Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

MicroNet MS/TP Network Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Cable Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Approved Cable Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

ADI and Remote I/O Module Network Wiring . . . . . . . . . . . . . . . . . . 31

Wiring Specifications for ADI or Remote I/O . . . . . . . . . . . . . . . . 31

I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Power Supply Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Introduction to BACnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Architecture Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

MS/TP Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Physical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Number of Connected Devices . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Logical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Addressing Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Limits to Number of Polled Points . . . . . . . . . . . . . . . . . . . . . . . . 43

Limits to Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Connection to an MS/TP Network . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Remote I/O Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Physical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Number of Connected Devices . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Logical Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Addressing Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Increased I/O Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

MS/TP Network Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Master and Slave Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Physical Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Required Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

MS/TP Address for BACnet Tools . . . . . . . . . . . . . . . . . . . . . . . . 47

Other Network Setup Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Port Bridging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Single Path to Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Routers and Network Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Network Setup Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Physical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Set the DIP Switches on the Controllers . . . . . . . . . . . . . . . . . . . . . . 52

iv MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

MS/TP Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Remote I/O Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Power on the MNB-xxxx Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Commission UNCs and ENCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Commission the Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Chapter 3 Checkout and Troubleshooting

Mechanical Hardware Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Communications Hardware Checkout . . . . . . . . . . . . . . . . . . . . . . . . . 55

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Field-replaceable Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

BACnet Best Practices

I/A Series MicroNet BACnet System Architecture Overview . . . . . . . . 64

MS/TP Network Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Master-Slave Token Passing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Device Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

BACnet Rules that Must be Followed . . . . . . . . . . . . . . . . . . . . . . . . . . 69

General BACnet Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

No Duplicate Device Instances . . . . . . . . . . . . . . . . . . . . . . . . . . 69

No Duplicate Object Identifiers within a Device . . . . . . . . . . . . . . 69

No Duplicate Network Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Devices on a Network Must Share a Single Network Number . . . 69

One Communication Path Only . . . . . . . . . . . . . . . . . . . . . . . . . . 69

MS/TP Network Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

No Duplicate Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Install Terminators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Set Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Use Proper Communication Cable . . . . . . . . . . . . . . . . . . . . . . . 72

Bond the Shield to a Proper Ground . . . . . . . . . . . . . . . . . . . . . . 72

BACnet Best Practice Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Selection of WP Tech Object Type for BACnet . . . . . . . . . . . . . . . . 73

MS/TP Network Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Keep Exposed Communication Conductors Short . . . . . . . . . . . . 73

Do Not Nick the Insulation When Removing the Cable Sheath . . 74

Make Low Resistance Terminations . . . . . . . . . . . . . . . . . . . . . . 74

Address Devices Consecutively . . . . . . . . . . . . . . . . . . . . . . . . . . 74

A Router’s Address Should Be 0 (Zero) . . . . . . . . . . . . . . . . . . . . 74

Few Controllers Per Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Use BACnet/IP for the MNB-1000 . . . . . . . . . . . . . . . . . . . . . . . . 74

Use Higher Baud Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Use Auto-baud to Change Baud Rate . . . . . . . . . . . . . . . . . . . . . 75

Add a Controller as MS/TP Slave After a Failed Upgrade . . . . . . 75

Power the Controllers Properly . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Repeaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Set MaxInfoFrames to Value Greater Than 1 . . . . . . . . . . . . . . . 76

Set the MaxMaster Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Tuning the MaxMaster Property . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Discussion of Joining Token Passing . . . . . . . . . . . . . . . . . . . . . 78

Table of Contents

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide v

Table of Contents

Understanding the Transmit and Receive Data LEDs on MS/TP Net-

works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

BACnet/IP Network Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Set the gateway address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Use BBMDs When Needed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

BACnet/IP Through a NAT Router . . . . . . . . . . . . . . . . . . . . . . . . 81

BACnet Ethernet Network Guidelines . . . . . . . . . . . . . . . . . . . . . . . . 81

BACnet/Ethernet is Not Routed . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Do Not Leave BACnet/Ethernet Enabled if Not Used . . . . . . . . . 81

BACnet Guidelines for UNCs and ENCs . . . . . . . . . . . . . . . . . . . . . 81

Fewer Points Equals Better Performance . . . . . . . . . . . . . . . . . . 81

Use Poll On Demand for Schedules, Alarms, and Trends . . . . . . 82

Delete Unused Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Keep the UNC or ENC Routing . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Keep the Processor Idle Time Above 20% . . . . . . . . . . . . . . . . . . 83

UNC and ENC Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Use COV Subscription for Slowly Changing Points . . . . . . . . . . . 83

Do Not Use COV for Priority Type Points . . . . . . . . . . . . . . . . . . . 84

Tuning Policy for ENC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

General BACnet Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Consider Network Design Carefully . . . . . . . . . . . . . . . . . . . . . . . 84

Remote Connectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

BBMDs–

Connecting BACnet/IP Devices on Different Subnets . . . . . . . . . . . 85

Setup of BBMD in the MNB-1000 . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Use of VPN for Off-site Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Using a BBMD with an NAT Router . . . . . . . . . . . . . . . . . . . . . . . . . 90

WP Tech/WPCT BACnet/IP Remote Connection Setup . . . . . . . . . 91

Performance Improvements for MS/TP . . . . . . . . . . . . . . . . . . . . . . . . . 94

Implementing Performance Im pr ov em e nts . . . . . . . . . . . . . . . . . . . . 94

COV Subscription in a UNC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

COV Subscription in an ENC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Using AdminTool Object to Change useCOV Value . . . . . . . . . . . . . 98

Preparation for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Performing a Search and Replace . . . . . . . . . . . . . . . . . . . . . . . 100

Optimizing the covIncrement Value . . . . . . . . . . . . . . . . . . . . . . . . 101

COV Subscription Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

covIncrement Value too Small . . . . . . . . . . . . . . . . . . . . . . . . . . 101

covIncrement Value too Large . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Choose the Right covIncrement Value . . . . . . . . . . . . . . . . . . . . 102

The Type of Point Affects COV Efficiency . . . . . . . . . . . . . . . . . . . 103

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Setting Up a Remote I/O Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Installing Remote I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Configuring Remote I/O Modules . . . . . . . . . . . . . . . . . . . . . . . . 105

The Remote I/O Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Understanding the Transmit and Receive Data LEDs on Remote I/O

Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

vi MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Table of Contents

Remote I/O Best Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

EOL Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Fallback Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide vii

Table of Contents

viii MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Preface

Purpose of this Manual

This TAC I/A Series MicroNet™ BACnet™ Wiring, Networking, and Best Practices Guide is a reference for creating a network of TAC I/A Series MicroNet BACnet controllers. This guide provides the following discussions and instructions for the TAC I/A Series MicroNet BACnet series:

• Best practices related to the configuration and maintenance of a T AC I/A

ries MicroNet BACnet system

• TAC I/A Series MicroNet BACnet Controllers and Remote I/O Modules,

d their features

• Controller and module wiring terminals and wiring recommendations

• Controller and module input and output specifications

• TAC I/A Series MicroNet Digital Wall Sensors and their features

• Diagnostic functions of the TAC I/A Series MicroNet Digital Wall Sensors

• BACnet overview

• TAC I/A Series MicroNet BACnet system architecture overview

• MS/TP and Remote I/O Network configuration, including physical and

ogical restrictions

• How to network into an IP over an Ethernet backbone

Other literature related to the implementation of a TAC I/A Series MicroNet BACnet system are referenced througho ut this gu ide an d ar e lis te d in

"Applicable Documentation,” on page x.

It is assumed that readers of this manual already understand basic HVAC concepts. An understanding of BACnet networking and communications, as well as a general understanding of Ethernet networks, is also helpful. This manual is written for:

• Applicatio n en gin eer s.

• Users who change hardware or control logic.

• Schneider Electric technicians and field engineers.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide ix

Applicable Documentation

F-Number Description Audience Purpose

Provides a programming reference for

F-27254

F-27255

F-27356

TAC I/A Series WorkPlace Tech Tool Engineering Guide.

TAC I/A Series WorkPlace Tech Tool User’s Guide

TAC I/A Series WorkPlace Tech Tool BACnet Engineering Guide Supplement

– Application Engineers – Service Personnel

– Application Engineers – Installers – Start-up Technicians – Service Personnel

– Application Engineers – Service Personnel

MicroNet controllers. Gives detailed descriptions for each of the Control Objects used with MicroNet controllers.

Provides step-by-step instructions for using the WorkPlace Tech Tool, version 4.0.

Provides supplemental information for programming MicroNet BACnet controllers. Gives detailed descriptions for each of the unique BACnet Control Objects used with these controllers.

F-27419

F-27358

F-27365

F-27461

F-27462

F-27463

F-27485

T AC I/A Series MicroNet BACnet Smoke Control Systems Manual

T AC I/A Series MicroNet BACnet WorkPlace Commissioning Tool and Flow Balance T ool User’s Guide

T AC I/A Series MicroNet BACnet MNB-70, MNB-300, MNB-V1, and MNB-V2 Controllers BACnet PIC Statement

T AC I/A Series MicroNet BACnet MNB-1000 Controller BACnet PIC Statement

TAC I/A Series UNC-520 Universal Network Controller BACnet PIC Statement

TAC I/A Series ENC-520 Enterprise Network Controller BACnet PIC Statement

T AC I/A Series ENS-1 Enterprise Network Server BACnet PIC Statement

– Application Engineers – Installers – Start-up Technicians – Service Personnel

– Application Engineers

Provides information for creating smoke control systems that meet a UL 864 UUKL/UUKL7 project specification, using MicroNet BACnet controllers.

Provides step-by-step instructions for using the WorkPlace Commissioning Tool and Flow Balance Tool.

Provides BACnet compliance information on MicroNet BACnet MNB-70, MNB-300, MNB-V1, and MNB-V2 controllers.

Provides BACnet compliance information on the MicroNet BACnet MNB-1000 controller.

Provides BACnet compliance information on the UNC-520 controller.

Provides BACnet compliance information on the ENC-520 controller.

Provides BACnet compliance information on the ENS-1 enterprise network server.

– Application Engineers – Installers – Service Personnel – Start-up Technicians

Provides step-by-step mounting and installation instructions for the MicroNet MNB-70 Controller.

Provides step-by-step mounting and installation instructions for the MicroNet MNB-300 Controller.

F-27456

F-27345

TAC I/A Series MicroNet BACnet MNB-70 Zone Controller Installation Instructions

TAC I/A Series MicroNet BACnet MNB-300 Unitary Controller Installation Instructions

x MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

F-Number Description Audience Purpose

Preface

TAC I/A Series MicroNet BACnet

F-27346

F-27347

F-27486

F-26277

MNB-V1, MNB-V2 VAV Controllers Installation Instructions

TAC I/A Series MicroNet BACnet MNB-1000 Plant Controller Installation Instructions

TAC I/A Series MicroNet BACnet MNB-1000-15 Remote I/O Module Installation Instructions

TAC I/A Series MicroNet MN-SX Series Sensors General Instructions

Conventions Used in this Manual

The following conventions apply to this printed manual:

• Menu commands appear in bold.

Example — On the Special menu, point to Security, then click Log On.

• Italics is used for emphasis in a statement, such as:

If maximum closed switch voltage is not more than 1.0 V and minimum open switch voltage is at least 4.5 V, then solid state switches may be used for a UI or a DI.

It is also used when referring to a document, such as: Refer to the WorkPlace Tech Tool BACnet Engineering Guide Supple-

ment, F-27356.

Acrobat (PDF) Conventions

If you are reading this manual online in Adobe® Acrobat® (.PDF file format), numerous hypertext links exist, both in normal black text and in blue text.

• Hypertext links in this document include all entries in the Table of

Contents, as well as cross-references within the body text. For ease of recognition, cross-reference links within the body text appear in blue type, for example Manual Summary. A link is indicated whenever the mouse pointer changes to a hand with a pointing finger.

• When viewing this guide with Adobe Acrobat, you can display various

“bookmark” links on the left side of your screen by choosing “Bookmarks and Page” from the “View” menu. As with the links described above, these “bookmark” links will also cause the mouse pointer to change to a hand with a pointing finger.

Abbreviations and Terms Used in this Manual

Refer to Glossary for definitions, abbre viations, and acron yms that may be used in this document:

Manual Summary The MicroNet BACnet Wiring, Networking, and Best Practices Guide

contains three chapters. Chapter 1, I/A Series BACnet Hardware, provides a brief overview of the

various I/A Series sensors.

Chapter 2, Networking Practices, provides an overview of the BACnet protocol and, more specifically, its implementation in the TAC I/A Series MicroNet BACnet system. This chapter then explains how TAC I/A Series MicroNet BACnet controllers and sensors are configured for an MS/TP network. It also explains how remote I/O networks are constructed by connecting one to eight remote I/O modules to an MNB-1000 controller.

Chapter 3, Checkout and T roubleshooting , provides steps for determini ng the proper operation of the TAC I/A Series MicroNet BACnet system and suggests corrective actions for any discovered faults.

Appendix A, BACnet Best Practices, provides best practices information for creating and maintaining a network of TAC I/A Series MicroNet BACnet controllers, remote I/O modules, and sensors, a nd pr ovides ad ditional d etail for information contained elsewhere in this document.

MicroNet BACnet controllers, remote I/O modules, and

xii MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Chapter 1 I/A Series BACnet Hardware

This chapter provides a brief overview of the various I/A Series MicroNet BACnet controllers and sensors, including:

• Common Controller Features

• BACnet Compliance

• MNB-300 Unitary Controller

• MNB-V1, MNB-V2 VAV Controllers

• MNB-70 Zone Controllers

• MNB-1000 Plant Controller

• MNB-1000-15 Remote I/O Module

• MicroNet Digital Wall Sensors (MN-Sx Series)

MicroNet BACnet hardware products include controllers and compa tible sensors.

• MicroNet BACnet controllers provide direct-digital control for packaged

rooftop, heat pump, fan coil, unit ventilator , and VAV, as well as complex mechanical equipment such as central station air handlers, VAV air handlers, and cooling towers. Five basic controller platforms are available, each with a number of I/O points and supp ort for a digital roo m temperature or humidity sensor (MicroNet sensor).

• MicroNet sensors are digital wall temperature and humidity sensors

designed specifically for use with MicroNet controllers. 12 different models offer varying levels of sensor push-buttons and LCD screens.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 1

Chapter 1

MicroNet BACnet Controllers

There are five hardware platforms for MicroNet BACnet controllers: the MNB-70, the MNB-300, the MNB-V1, the MNB-V2, and the MNB-1000. In addition, the MicroNet BACnet family includes the MNB-1000-15 remote I/O module. Each of these platforms is described in the following sections.

Common Controller Features

BACnet Compliance

While all controller platforms differ by their physical characteristics and numbers and types of I/O points, all controller plat forms provide the following common features:

Note: See"MNB-1000-15 Remote I/O Module" on page 13 for features of the remote I/O module.

• 24 V ac powered.

• Capability to function in standalone mode or as part of an I/A Series

building automation network.

• Support for a digital MicroNet sensor via a Sensor Link (S-Link) bus.

• Sequence of operation and BACnet image are fully programmable using

WorkPlace Tech Tool (WP Tech) 5.0 or greater.

• Extensive BACnet object and services support.

• DIP switch for setting the physical address.

• LED indication of MS/TP communication link and activity, and controller

status.

• Isolated EIA-485 (formerly RS-485) transceiver for MS/TP

communications.

• Firmware upgradeable over the network or directly to the controller.

Each MicroNet BACnet controller conforms to the requirement s of a BACnet Application Specific Device (B-ASD). For a list of objects suppor ted by these controllers, and the services provided, refer to the BACnet PIC Statements, available on the BACnet Testing Laboratories website

(http://www.bacnetinternational.net/btl/).

2 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

MNB-300 Unitary Controller

The I/A Series MicroNet BACnet Unitary Controller, MNB-300, is an interoperable controller with native BACnet MS/TP communications support. The controller features Sensor Link (S-Link) support, LED status and output indication, screw terminal blocks, as well as a panel-mou nt su b- base w ith removable electronics module. The MNB-300 also includes one end-of-line (EOL) termination and two bias resistors, both of which are jumper-selectable.

When programmed using WP Tech, the MNB-300 provides a wide range of control strategies for packaged rooftop, heat pump, fan coil, unit ventilator, and similar applications.

Unique Features

In addition to common MicroNet BACnet controller features ("Common

Controller Features" on page 2), the MNB-300 offers the following:

• Removable electronics module that mates with panel-mounted subbase.

• Optional NEMA 1 enclosure.

• IAM button for BACnet “I am” message broadcast.

• Integral MS/TP jack for direct connection of a PC with the WP Tech.

• Removable terminals for power and communications, to facilitate

commissioning.

• LED indication of UO and TO state.

Memory Available

T able–1.1 MNB-300 Available Memory.

Model

Number

MNB-300 256 KB 8 KB n/a 4 KB 8 KB

Physical I/O Points

T able–1.2 MNB-300 Inputs and Output s.

Model

Number

MNB-300 636

Refer to "Input and Output Spe cifications" on page 15 for a detailed discussion of each input or output type.

Time Clock

The

MNB-300 controller uses a software clock. This software clock defaults to

a predefined Date/Time following a reset.

Flash SRAM SDRAM EEPROM FRAM

Inputs and Outputs

UI UO DO (Triac)

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 3

Chapter 1

MS/TP Jack

EOL

Enable

Disable

TO1 (DO1)

TO2 (DO2)

TO3 (DO3)

TO4 (DO4)

TO5 (DO5)

TO6 (DO6)

UI1

COM

UI2

UI3

COM

UI4

UI5

COM

UI6

UO1

COM

UO2

UO3

COM

S-LK

IAM

MS+

MS-

SLD

MSB

LSB

MNB-300

Unitary Controller

24H

24G COM

GND

XMT

RCV

STATUS

Physical Address

EN DIS

MS BIAS

Note: Components are

shown in their approximate locations.

Universal Inputs

0 to 5 Vdc 0 to 20 mA 10K Thermistor 1K Balco 1K Platinum 1K Resistive 10K Resistive Digital (dry switched

contact)

Standard Pulse

Fast Pulse (UI1)

Universal Outputs 0 to 20 mA into an 80 to 550

ohm load

S-LK Supports one TAC I/A Series MN-Sxxx Sensor

BACnet Network MS/TP Communications

AC Power

20.4 to 30 Vac 50/60 Hz Class 2 (EN 60742) 16 VA per controller

Digital Outputs (Triac) 12 VA at 24 Vac, 50/60 Hz. Each Triac output individually isolated from AC input and other I/O. Class 2

7 8

2 3

1 Do not exceed two AWG #24

(0.205 mm

) wires per MS/TP

wiring terminal.

2 Power and I/O point wiring

terminals accept up to two AWG #14 (2.08 mm

) or smaller wires.

3 Power and MS/TP connectors

have removable screw terminals

4 Input signals of 1 to 11 Vdc must

be converted to 0.45 to 5 Vdc with a voltage divider, part number AD-8961-220.

5 In applications requiring universal

inputs with ranges of 0 to 20 mA, a 250 ohm

shunt resistor kit, part

number AD-8969-202, is needed.

6 An 11 kilohm shunt resistor kit, part

number AD-8969-206, is required for a 10 kilohm Thermistor Sensor (non-850 series) universal inputs.

7 To detect a closed switch, resistance must

be less than 300

ohm

8 To detect an open switch, resistance must

be greater than 2.5

kilohm

9 External load is not required to illuminate

UO LEDs.

10 Minimum rate of 1 pulse per 4 minutes.

Maximum rate of 1 pulse per second.

11 MS/TP network bias resistors are shipped

in the disabled setting, and are located under the controller’s cover.

12 Minimum rate of 1 pulse per 4 minutes.

Maximum rate of 10 pulses per second.

13 When making an MS/TP cable, use a

1.3 x 3.5 mm Vdc power plug with strain relief (Vimex part number SCP-2009A-T, TAC part number E24-1442, or equivalent). The cable should be no longer than 6 ft. Connect MS+ to the center contact and MS– to the outside contact:

Note: The MS/TP cable described above is available from Schneider-Electric as MNB-CT-CBL. Contact Schneider-Electric for more information.

TO (DO) LEDs (6)

UO LEDs (3)

Internal

Triac

Switches

(Isolated)

Connectors (2)

Figure–1.1 MNB-300 Terminal Connections.

Wiring Terminals

Refer to Figure-1.1 for the power and network communications wiring connections available on the MNB-300 controller.

4 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

SW24H1

SW24H2

SW24H3

24H

24G(COM)

GND

STATUS MSTP RCV

MSTP XMT

UO 1

COM

UI 1

COM

UI 2 UI 3

S-LK/COM

MSTP +

SHLD

MSTP -

MNB-V1, MNB-V2 VAV Controllers

The I/A Series MicroNet BACnet VAV (Variable Air Volume) Controllers, MNB-V1 and MNB-V2, are interoperable controllers with native BACnet MS/TP communications support. Both models incor p or at e: an inte gr a l actuator with manual override; an integral, patented, pressure transducer; three universal inputs; Sensor Link (S-Link) support; LED st atus indication; and over-the-shaft damper mounting. The MNB-V1 controller is designed specifically for cooling applications, while the MNB-V2 controller adds digital and universal outputs that make it suitable for additional VAV applications.

When programmed using WP Tech, these controllers provide a wide range of control strategies for pressure-dependent and pressure-independent terminal boxes, with or without reheat capabilities.

Unique Features

In addition to common MicroNet BACnet controller features ("Common

Controller Features" on page 2), the MNB-V1 and MNB-V2 offer the

following:

• Air balancing performed using WorkPlace Flow Balance Tool (WPFBT).

• Integrated packaging with actuator, pressure transducer, and controller.

• Integral actuator features manual override and travel limit stops for easy

set up and adjustment.

• Enclosure approved for use in air plenums.

• Damper position feedback to the BACnet Building Automation System

(BAS) via integral hall effect sensor.

• Stable flow control down to 0.004 in. W.C. (0.996 Pa) differential

pressure.

Memory Available

Table–1.3 MNB-Vx Available Memory.

Model

Number

MNB-V1 MNB-V2

Flash SRAM SDRAM EEPROM FRAM

256 KB 8 KB n/a 4 KB n/a

Physical I/O Points

Table–1.4 MNB-Vx Inputs and Outputs.

Model

Number

Inputs and Outputs

UI UO DO (Triac)

MNB-V1 300 MNB-V2 313

Refer to the "Input and Output Specifications" on page 15 for a detailed discussion of each input or output type.

Time Clock

The

MNB-V1 and MNB-V2 controllers use a software clock. This software clock

defaults to a predefined Date/Time following a reset.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 5

Chapter 1

UO1*

COM*

UI1

COM

UI2

UI3

S-LK/COM

S-LK

MSTP +

MSTP –

SHLD

SW24H1* (DO1)

SW24H2* (DO2)

SW24H3* (DO3)

24H

24G (COM)

GND

MSTP RCV

MSTP XMT

STATUS

Physical

Address

MSB

LSB

MNB-V1 / -V2

Controllers

MS/TP Jack

6 To detect an open switch, minimum resistance must be

greater than 2.5 kilohm.

7 Minimum rate of 1 pulse per 4 minutes. Maximum rate of

1 pulse per second.

8 When making an MS/TP cable, use a 1.3 x 3.5 mm Vdc

power plug with strain relief (Vimex part number SCP-2009A-T, Schneider-Electric part number E24-1442, or equivalent). The cable should be no longer than 6 ft. Connect MS+ to the center contact and MS– to the outside contact:

Note: The MS/TP cable described above is available from Schneider-Electric as MNB-CT-CBL. Contact Schneider-Electric for more information.

1 Fixed screw terminals that accept a single AWG #14

(2.08 mm

) wire or up to two AWG #18 (0.823 mm2) or

smaller wires. Do not exceed two AWG #24 (0.205 mm

)

wires per MS/TP wiring terminal.

2 Input signals of 1 to 11 Vdc must be converted to 0.45 to

5 Vdc with a voltage divider, part number AD-8961-220.

3 In applications requiring universal inputs with ranges of

0 to 20 mA, a 250 ohm shunt resistor kit, AD-8969-202, is needed.

4 An 11 kilohm shunt resistor kit, AD-8969-206, is

required for a 10 kilohm

Thermistor Sensor (non-850

series) universal inputs.

5 To detect a closed switch, maximum resistance must

be less than 300 ohm.

AC Power

20.4 to 30 Vac, 50/60 Hz Class 2 (EN 60742) 15 VA per controller plus DO load

Digital Outputs Total 24 VA (DO1+DO2), 12 VA (DO3) at 24 Vac, 50/60 Hz, Class 2. Pilot Duty

Universal Output 0 to 20mA into an 80 to 550

ohm

load

S-LK Supports one I/A Series MN-Sxxx Sensor

BACnet Network Communications

5 6

Universal Inputs

0 to 5 Vdc 0 to 20 mA 10K Thermistor 1K Balco 1K Platinum 1K Resistive 10K Resistive Digital (dry switched

contact)

Standard Pulse

Internal Triac Switches (3)

Note: Components are shown in

their approximate locations.

Note: Asterisks (*) indicate terminals

that apply to the MNB-V2 controller but not to the MNB-V1.

Figure–1.2 MNB-Vx Terminal Connections.

Wiring Terminals

Refer to Figure-1.2 for the power and network communications wiring connections available on the MNB-V1 and MNB-V2 controllers.

6 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

MNB-70 Zone Controllers

SW24H1

SW24H2

SW24H3

24H

24G(COM)

GND

STATUS

MSTP RCV MSTP XMT

UO 1

COM

UI 1

COM

UI 2 UI 3

S-LK/COM

MSTP +

MSTP -

SHLD

The I/A Series MicroNet BACnet Zone Controller, MNB-70, is an interoperable controller with native BACnet MS/TP communications support. The controller features: three universal inputs; one universal output; three digital (Triac) outputs; Sensor Link (S-Link) support; LED status indication; and screw terminal blocks.

When programmed using WP Tech, the MNB-70 provides a wide range of control strategies for heat pump, fan coil, unit ventilator, mixing boxes, and similar applications.

Unique Features

In addition to common MicroNet BACnet controller features ("Common

Controller Features" on page 2), the MNB-70 offers the following:

• I-Am button for BACnet “I-am” message broadcast.

• Integral MS/TP jack for direct connection of a PC with the WP Tech.

• Small footprint.

• Enclosure approved for use in air plenums.

Memory Available

Table–1.5 MNB-70 Available Memory.

Model

Number

MNB-70 256 KB 8 KB n/a 4 KB n/a

Flash SRAM SDRAM EEPROM FRAM

Physical I/O Points

Table–1.6 MNB-70 Inputs and Outputs.

Model

Number

Inputs and Outputs

UI UO DO (Triac)

MNB-70 313

Refer to the "Input and Output Specifications" on page 15 for a detailed discussion of each input or output type.

Time Clock

The

MNB-70 controller uses a software clock. This software clock defaults to a

predefined Date/Time following a reset.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 7

Chapter 1

UO1

COM

UI1

COM

UI2

UI3

S-LK/COM

S-LK

MSTP +

MSTP –

SHLD

SW24H1 (DO1)

SW24H2 (DO2)

SW24H3 (DO3)

24H

24G (COM)

GND

MSTP RCV

MSTP XMT

STATUS

Physical Address

MSB

LSB

MNB-70

Controller

MS/TP Jack

IAM

1 Fixed screw terminals that accept a single AWG #14

(2.08 mm

) wire or up to two AWG #18 (0.823 mm2) or

smaller wires. Do not exceed two AWG #24 (0.205 mm

)

wires per MS/TP wiring terminal.

2 Input signals of 1 to 11 Vdc must be converted to 0.45 to

5 Vdc with a voltage divider, part number AD-8961-220.

3 In applications requiring universal inputs with ranges of

0 to 20 mA, a 250 ohm shunt resistor kit, AD-8969-202, is needed.

4 An 11

kil

ohm shunt resistor kit, AD-8969-206, is

required for a 10

kilohm

Thermistor Sensor (non-850

series) universal inputs.

5 To detect a closed switch, maximum resistance must

be less than 300 ohm.

AC Power

20.4 to 30 Vac, 50/60 Hz Class 2 (EN 60742) 15 VA per controller plus DO load

Digital Outputs Total 24 VA (DO1+DO2), 12 VA (DO3) at 24 Vac, 50/60 Hz, Class 2. Pilot Duty

Universal Output 0 to 20mA into an 80 to 550

ohm

load

S-LK Supports one I/A Series MN-Sxxx Sensor

BACnet Network Communications

5 6

Universal Inputs

0 to 5 Vdc 0 to 20 mA 10K Thermistor 1K Balco 1K Platinum 1K Resistive 10K Resistive Digital (dry switched

contact)

Standard Pulse

Internal Triac Switches (3)

6 To detect an open switch, minimum resistance must be

greater than 2.5

kilo

hm.

7 Minimum rate of 1 pulse per 4 minutes. Maximum rate of

1 pulse per second.

8 When making an MS/TP cable, use a 1.3 x 3.5 mm Vdc

Note: The MS/TP cable described above is available from Schneider-Electric as MNB-CT-CBL. Contact Schneider-Electric for more information.

Note: Components are shown in

their approximate locations.

Figure–1.3 MNB-70 Terminal Connections.

Wiring Terminals

Refer to Figure-1.3 for the power and network communications wiring connections available on the MNB-70 controller.

8 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

MNB-1000 Plant Controller

The I/A Series MicroNet BACnet Plant Controller, MNB-1000, is an interoperable controller with native BACnet MS/TP communications support. The controller features Sensor Link (S-Link) support, LED status and output indication, two Ethernet ports, and screw terminal blocks.

The MNB-1000’s sequence of operation and BACnet image are fully programmable using WP Tech, and can be applied to a wide range of mechanical equipment. Typical applications include central station air handlers, VAV air handlers, and cooling towers.

Unique Features

In addition to common MicroNet BACnet controller features ("Common

Controller Features" on page 2), the MNB-1000 offers the following:

• Optional NEMA 1 enclosure.

• IAM button for BACnet “I am” message broadcast.

• Integral MS/TP jack for direct connection of a PC with the WP Tech.

• LED indication of Ethernet communication link and activity, DO state,

UO state, and remote I/O communications.

• Application-programmable LED provides on/off indication of a

user-defined application parameter.

• BACnet router functionality.

• Support for remote I/O modules.

• Etherne t po rt bridgin g.

• 20 Vdc output

• 72 hour, battery-backed real time clock.

Memory Available

Table–1.7 MNB-1000 Available Memory.

Component Flash SRAM SDRAM EEPROM FRAM

µC 128 KB 4 KB n/a 4KB n/a

Motherboard n/a 256 KB n/a 128 KB n/a Engine (Core) 32 or 16 MB Engine (Boot) 2 MB n/a n/a n/a n/a

a. MNB-1000s with a date code prior to 0726 have 32 MB of core memory. Beginning with

date code 0726, core memory was changed to 16 MB. However, because the MNB-1000 has always used only the first 16 MB of memory, this change has no impact on the controller’s operation, the size of the application allowed, or the controller’s application compatibility.

Physical I/O Points

Table–1.8 MNB-1000 Inputs and Outputs.

Model

MNB-1000 12488

Refer to the "Input and Output Specifications" on page 15 for a detailed discussion of each input or output type.

n/a 64 MB 1 Kb n/a

Inputs and Outputs

UI DI UO DO (Triac)

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 9

Chapter 1

Note: The onboard I/O points of the MNB-1000 can be greatly expanded

with the addition of one to eight MNB-1000-15 remote I/O modules, each of which adds 15 I/O points. Refer to "MNB-1000-15 Remote I/O Module" on

page 13.

Time Clock

The MNB-1000 features an onboard, real-time clock. A lithium battery provides backup power for up to 72 hours in the event of a primary power interruption. The real-time clock acts as a Date/Time server using native BACnet services. In the absence of another Date/Time server on the network, the MNB-1000 can provide this functionality to other nodes on the BACnet internetwork.

Battery Replacement

If the real-time clock’s battery becomes depleted, replace it with lithi um battery, part number E17-137, according to the instructions in Figure-1.4. For additional disassembly and reassembly instructions, refer to MicroNet BACnet MNB-1000 Plant Controller Installation Instructions, F-27347

Caution: Follow static discharge precautions when hand ling the MNB-1000 and its component parts.

Note: Whenever the battery is removed from the MNB-1000, the clock setting and volatile data will be lost. Reprogram the MNB-1000 as needed after installing the replacement battery.

10 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

Printed Circuit Board

Cover

Base Plate

Printed Circuit

Board

Screw

(1 of 2)

Lithium Battery

E17-137

1 If the controller is mounted inside an

enclosure, open the enclosure cover.

2 Remove power from the

controller.

3 Referring to MicroNet BACnet

MNB-1000 Controller Installation Instructions, F-27347, remove

the controller’s main assembly from the base plate.

4 Remove two screws, and then

separate the printed circuit board from the cover.

5 Locate the battery on the printed

circuit board.

6 Remove the depleted battery,

and then install a new lithium battery, part number E17-137. Make sure that the positive (+) side faces upward.

7 Reassemble the printed

circuit board to the cover, and secure with the two screws removed in step 4.

8 Referring to F-27347,

reassemble the controller’s main assembly to the base plate.

9 Restore power to the controller.

10 If applicable, close the enclosure

cover.

Figure–1.4 MNB-1000 Real-time Clock Battery Replacement.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 11

Chapter 1

Figure–1.5 MNB-1000 Terminal Connections.

Wiring Terminals

Refer to Figure-1.5 for the wiring connections available on the MNB-1000 controller.

20 Vdc Output

±10% at

20 Vdc 100 mA

Universal Inputs

0 to 5 Vdc 0 to 20 mA

5 10K Thermistor 1K Balco 1K Platinum 1K Resistive 10K Resistive Digital (dry switched contact)

Digital Inputs Dry Switched Contact Fast Pulse

Local Display (for future use)

S-LK Supports one I/A Series MN-Sxxx Sensor

ADI or Remote I/O

BACnet Network Communications

1 I/O point wiring terminals

accept a single AWG #14 (2.08 mm

) or up to two

AWG #18 (0.823 mm2) or

20V

UI1

COM

UI2

UI3

COM

UI4

UI5

COM

UI6

UI7

COM

UI8

UI9

COM

UI10

UI11

COM

UI12

DI1

COM

DI2

DI3

COM

DI4

COM

S-LK

IO+

IO-

SLD

MS+

MS-

SLD

Note: Components are

Disable Enable

I AM

MS/TP Jack

shown in their approximate locations.

0 PORT

IO EOL MS BIAS MS EOL MS BIAS

ACT LNK

1 PORT

Physical Address

Plant Controller

smaller wires. Do not exceed two AWG #24 (0.205 mm

) wires per MS/TP or Remote I/O wiring terminal.

2 Power wiring terminals accept up to two AWG #14

(2.08 mm

) or smaller wires.

3 Power, MS/TP, and Remote I/O connectors have

removable screw terminals.

4 Input signals of 1 to 11 Vdc must be converted to 0.45 to

5 Vdc with a voltage divider, part number AD-8961-220.

5 In applications requiring universal inputs with ranges of 0 to

20 mA, a 250

ohm

shunt resistor kit, AD8969-202, is

needed.

6 An 11 kil

for a 10 kil

ohm

shunt resistor kit, AD-8969-206, is required

ohm

thermistor Sensor (non-850 series)

universal inputs.

MNB-1000

Internal Triac

Switches (8)

(Isolated)

TO (DO) LEDs (8)

24H

24G COM

GND

TO1 (DO1)

TO2 (DO2)

TO3 (DO3)

TO4 (DO4)

TO5 (DO5)

TO6 (DO6)

TO7 (DO7)

TO8 (DO8)

2 3

AC Power

20.4 to 30 Vac 50/60 Hz Class 2 (EN 60742) 50 VA per controller Isolated from I/O

Digital Outputs 12 VA at 24 Vac, 50/60 Hz each Triac output individually isolated from AC input and other I/O.

Universal Outputs 0 to 20 mA into an 80 to 550 ohm load.

7 To detect a closed

switch, maximum resistance must be less than 300

8 Remote I/O network

bias resistor is built-in.

minimum resistance must be greater than 2.5 kil

ETHERNET

LSB

UO LEDs (8)

RCV

XMT

MSTP

STATUS AUX

UO1

COM

UO2

UO3

COM

UO4

UO5

COM

UO6

UO7

COM

UO8

9 To detect an open switch,

10 To detect an open switch,

minimum resistance must be equal to or greater than

2.5 kil

MSB

ohm

11 External load is required to

illuminate UO LEDs.

12 Minimum rate of 1 pulse per 4 minutes. Maximum rate of 10 pulses

per second. With digital inputs only.

13 When making an MS/TP cable, use a 1.3 x 3.5 mm Vdc power

plug with strain relief (Vimex part number SCP-2009A-T, Schneider-Electric part number E24-1442, or equivalent). The cable should be no longer than 6 ft. Connect MS+ to the center contact and MS– to the outside contact:

–

Note: The MS/TP cable described above is available from Schneider-Electric as MNB-CT-CBL. Contact

Schneider-Electric for more information.

ohm

12 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

MNB-1000-15 Remote I/O Module

The I/A Series MicroNet BACnet Remote I/O Module, MNB-1000-15, is designed to be connected to an MNB-1000 Plant Controller, so as to expand the controller’s I/O count. When programmed using WP Tech, each module increases the count by 15 inputs and outputs. Up to ei ght modules can be connected to a given MNB-1000, for a potential increase of 120 I/O points, total. In this way, the controller’s existing 32 onboard I/O can be e xpanded to 47 I/O points (with one module), up to a maximum total of 152 I/O points (with eight modules).

Features

The MNB-1000-15 offers the following:

• 24 Vac powered.

• DIP switch for setting the physical address on the remote I/O network.

• Isolated EIA-485 (formerly RS-485) transceiver for remote I/O

communications.

• Removable electronics module that mates with panel-mounted subbase.

• Optional NEMA 1 enclosure.

• Removable terminals for power and communications, to facilitate

commissioning.

• LED indication of compatibility, UO and TO state, and communication

state (with the MNB-1000).

• Firmware upgradeable over the network.

• Fallback function, in case of loss of communication with MNB-1000.

Note: The MNB-1000-15 does not support the S-Link bus.

Memory Available

Table–1.9 MNB-1000-15 Available Memory.

Model

Number

MNB-1000-15 256KB 8KB n/a 4KB 8KB

Physical I/O Points

T able–1.10 MNB-1000-15 Inputs and Outputs.

Model

Number

MNB-1000-15 636

Refer to "Input and Output Spe cifications" on page 15 for a detailed discussion of each input or output type.

Fallback Function

The MNB-1000-15 module’s outputs are driven directly by the MNB-1000 Plant Controller, in which the application resides. If communications between the module and the MNB-1000 is lost, the module’s output s are set to fallback values that were previously sent to the module during normal communications. Refer to "Fallback Function" on page 107 for more information on this function.

Flash SRAM SDRAM EEPROM FRAM

Inputs and Outputs

UI UO DO (Triac)

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 13

Chapter 1

EOL

Enable

Disable

TO1 (DO1)

TO2 (DO2)

TO3 (DO3)

TO4 (DO4)

TO5 (DO5)

TO6 (DO6)

UI1

COM

UI2

UI3

COM

UI4

UI5

COM

UI6

UO1

COM

UO2

UO3

COM

S-LK

IO+

SLD

MSB

LSB

MNB-1000-15

Remote I/O Module

24H

24G COM

GND

XMT

RCV

STATUS

Physical Address

Universal Inputs

0 to 5 Vdc 0 to 20 mA 10K Thermistor 1K Balco 1K Platinum 1K Resistive 10K Resistive Digital (dry switched

contact)

Standard Pulse (UI1-UI6)

Universal Outputs 0 to 20 mA into an 80 to 550 ohm load

Remote I/O Network Communications to MNB-1000

AC Power

20.4 to 30 Vac 50/60 Hz Class 2 (EN 60742) 16 VA per module

Digital Outputs (Triac)

12 VA at 24 Vac, 50/60 Hz. Each Triac output individually isolated from AC input and other I/O. Class 2

7 8

2 3

1 Do not exceed two AWG #24

(0.205 mm

) wires per Remote I/O

wiring terminal.

2 Power and I/O point wiring

terminals accept up to two AWG #14 (2.08 mm

) or smaller wires.

3 Power and remote I/O connectors

have removable screw terminals

4 Input signals of 1 to 11 Vdc must

be converted to 0.45 to 5 Vdc with a voltage divider, part number AD-8961-220.

5 In applications requiring universal inputs

with ranges of 0 to 20 mA, a 250 ohm shunt resistor kit, part number AD-8969-202, is needed.

6 An 11

kil

ohm shunt resistor kit, part number AD-8969-206, is required for a 10

kil

ohm Thermistor Sensor (non-850

series) universal inputs.

7 To detect a closed switch, resistance must

be less than 300

ohm

8 To detect an open switch, resistance must

be greater than 2.5 kil

ohm

9 External load is not required to

illuminate UO LEDs.

10 Minimum rate of 1 pulse per 4 minutes.

Maximum rate of 1 pulse per second.

11 Items in gray, although present, are not

used in the MNB-1000-15.

12 Bias for the remote I/O network is

provided by the built-in bias resistor on the MNB -1000 controller.

TO (DO) LEDs (6)

UO LEDs (3)

Internal

Triac

Switches

(Isolated)

Connectors (2)

11 12

Note: Components are shown

in their approximate locations.

Figure–1.6 MNB-1000-15 Terminal Connections.

Wiring Terminals

Refer to Figure-1.6 for the power and network communications wiring connections available on the MNB-1000-15 remote I/O module.

14 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

UI1

COM

UI2

Controller

UI1

COM

UI2

+ _

250 ohm

UI1

COM

UI2

10 kilohm Thermistor

(with an 11 kilohm

shunt resistor)

4 to 20 mA

Transmitter

0 to 5 Vdc

Transmitter

Controller

Inputs

Controller

Inputs

Sensor Power

Source

Sensor Power

Source

1 Resistor kit, AD-8969-202. Be

sure to install the resistor at the controller, not at the 4 to 20 mA device.

Figure–1.7 Universal Input Connections.

Input and Output Specifications

All MicroNet BACnet controllers use input and output types as described in this section.

Universal Inputs

The universal input characteristics are software-configured to respond to one of the eight input types listed in Table–1.11.

Table–1.11 Universal Inputs.

Input Characteristics

10 kilohm Thermistor with 11 kilohm Shunt Resistor

1kilohm Balco

1 kilohm Platinum 1 kilohm Resistive 0 to 1500 ohm.

10 kilohm Resistive 0 to 10.5 kilohm. Analog Voltage Range 0 to 5 Vdc

Analog Current

Digital

Sensor operating range -40 to 250 °F (-40 to 121 ° C), requires Schneider Electric model TSMN-57011-850 series, TS-5700-850 series, or equivalent.

-40 to 250 °F (-40 to 121 °C), Schneider Electric model TSMN-81011, TS-8000 series, or equivalent.

-40 to 240 °F (-40 to 116 °C), Schneider Electric model TSMN-58011, TS-5800 series, or equivalent.

0 to 20 mA, requires external 250 ohm shunt resistor kit, AD-8969-202.

Dry switched contact; detection of closed switch requires less than 300 ohm resistance; detection of open switch requires more than 2.5 kilohm.

See Figure-1.7 for examples of connections to universal inputs.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 15

Chapter 1

UO1

COM

UO2

+ _

500 ohm

Controller

Outputs

+ _

UO1

COM

UO2

1 Output accuracy degrades as input

impedance decreases.

2 Resistor kit, AM-708. Be sure to

install the resistor at the 0 to 10 Vdc

device, not at the controller.

3 Can be purchased through PS3,

part number FUN-RIBU1-C.

Controller

Outputs

4 to 20 mA

Actuator

Controller Output

Configured as

0 to 20 mA

Functional Devices

RIBU1C Relay

0 to 10 Vdc

Actuator

N/C

COM

N/O

Wht/Blu 10-30 Vdc

Wht/Yel COM

UO1

COM

Figure–1.8 Universal Output Connections.

Figure–1.9 Fixed Digital Input Connections.

Universal Outputs

0 to 20 mA (output load from 80 to 550 ohm). See Figure-1.8 for examples of connections to universal outputs.

Digital Inputs

Dry switched contact. Detection of a closed switch requires less than 300 ohm resistance. When connected to a controller’s digital inputs, detection of an open switch requires more than 2.5 kilohm. When connected to a controller’s universal inputs (used as digit al inputs), d etection of an open switch requires more than 2.5 kilohm. See Figure-1.9 for examples of a connection to digital inputs.

Connection to Digital Inputs Connection to Universal Inputs

DI Input

On-Off Type Device

COM

Controller

Inputs

DI1

COM

DI2

DI Input

On-Off Type Device

COM

Controlle

Inputs

UI1

COM

UI2

16 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

Figure–1.10 MNB-V2 and MNB-70 Controller Triac Output Circuit Configuration.

GND 24H24G

SW24H1

(DO1)

SW24H2

(DO2)

SW24H3

(DO3)

Class 2

Transformer

24 Vac Primary

Load1 Load2 Load3

MNB-V2

Controller

Digital Output s, Triac

MNB-V2 and MNB-70

Table–1.12 lists specifications for the Triac outputs featured on the MNB-V2

and MNB-70 controllers.

Caution: The Triac (digital) output s o n MicroNet BACnet controller s are not protected against short circuits. Take necessary precautions to protect these outputs against short circuits.

Table–1.12 Digital Outputs, Triac, on MNB-V2 and MNB-70.

Input Characteristics

Internally sourced, high side switching. Triac outputs

Common Terminal

share a common supply (24H) that is independently switched to each output terminal, SW24H1, SW24H2, and SW24H3 (DO1, DO2, and DO3).

Rating (DO1+DO2) Rating (DO3)

24 VA total at 24 Vac, 50/60 Hz. 12 VA at 24 Vac, 50/60 Hz.

Default Output State OFF (inactive).

a. As with all Triac devices, a high-impedance meter on the output without a load will show

24 Vac, due to low level leakage through the device.

b. As labeled on the controller, SW24H1=DO1, SW24H2=DO2, and SW24H3=DO3 (see

Figure-1.2).

See Figure-1.10 for an example of a connection to an MNB-V2 or MNB-70 controller’s Triac outputs.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 17

Chapter 1

Figure–1.11 MNB-300 Controller , MNB-1000 Controller, and MNB-1000-15 Remote

I/O Module Triac Output Circuit Configuration.

Note: With the MNB-V2 and MNB-70, AC voltage to Triacs is sourced from the controller . This is different fr om the MNB-300 and MNB-1000 contr ollers, and the MNB-1000-15 module, where AC voltage is sourced externally.

MNB-300, MNB-1000, and MNB-1000-15

Table–1.13 lists specifications for the Triac outputs featured on MNB-300

and MNB-1000 controllers, and on the MNB-1000-15 remote I/O module.

Caution: The Triac (digit al) outp ut s on Mi croNet BACnet contro llers are not protected against short circuits. Take necessary precautions to protect these outputs against short circuits.

Table–1.13 Digital Outputs, Triac, on MNB-300, MNB-1000, and MNB-1000-15.

Input Characteristics

Isolation Each output individually isolated from circuit common. Common Terminal Rating 12 VA at 24 Vac, 50/60 Hz.

Default Output State OFF (inactive).

a. As with all Triac devices, a high-impedance meter on the output without a load will show

24 Vac, due to low level leakage through the device.

Each TO has its own common terminal. This is the voltage switched to each TO output.

See Figure-1.11 for an example of a connection to the Triac outputs on an MNB-300, MNB-1000, or MNB-1000-15.

24 Vac

Load1

TO1 (DO1) C1

GND

Load2

TO2 (DO2) C2

24H24G

Class 2

Transformer

24 Vac Primary

24 Vac

TOx (DOx) Cx

24 Vac

Loadx

20 Vdc Output

20 Vdc ±10% at 100 mA for supplying power to an external device. See

Figure-1.12 for an example of a connection to a 20 Vdc output.

18 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

Figure–1.12 20 Vdc Output Connection.

ControllerAuxiliary Device

–

Humidity 4 to 20 mA

(example)

250 ohm

20V

UI1

COM

1 Resistor kit, AD-8969-202,

4 to 20 mA only. Not required for Vdc.

Inputs from MN-Sx MicroNet Sensor

Table–1.14 lists specifications for the inputs from MicroNet Sensors. For an

example showing how a MicroNet Sensor may be wired to a MicroNet BACnet controller, see Figure-1.13.

Table–1.14 Inputs from MN-Sx MicroNet Sensor.

Input Characteristics

Space Temperature 32 to 122 °F (0 to 50 °C). Space Humidity 5 to 95% RH, non-condensing.

Local Setpoint Override Pushbutton For standalone occupancy control.

Fan Operation and Speed Mode

System Mode Heat, cool, off, or auto. Emergency Heat Enable or disable.

Adjustable within limits set by application programming tool.

On/off, speed (low/medium/high), or auto.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 19

Chapter 1

Wire S-Link to terminals 1 and 2 on baseplate

1 MS/TP wiring of controller to sensor screw terminals

is optional. Note: To preserve the integrity of the network, the MS/TP network wiring connecting a MicroNet BACnet controller to an MN-Sx sensor must be run to the sensor and back, in daisychain fashion. A wire “spur” must not be used to connect the sensor to the controller.

2 Observe consistent polarity when wiring.

3 S-Link wiring is not polarity-sensitive.

4 Tie the MS/TP shields together at the sensor.

5 MS/TP shields must be connected to the SLD (or SHLD)

terminal of all MicroNet BACnet controllers.

6 S-Link communications is not supported in the

MNB-1000-15 remote I/O module.

To Rest of the

MS/TP Network

To Rest of the

MS/TP Network

S-Link

MN-Sx

Sensor

MS/TP

MS/TP Jack

S-Link Jack

Shield

Controller

COM

SLK

SLD (SHLD)

MS+ (MSTP+)

MS- (MSTP-)

Wire MS/TP to terminals 3 and 4 on baseplate

Figure–1.13 Sensor Link (S-Link) Connection.

20 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Velocity Pressure Input

MNB-V1 and MNB-V2

Table–1.15 lists specifications for the velocity pressure inputs on MNB-Vx

controllers.

Table–1.15 Velocity Pressu re Input, on MNB-V1 and MNB-V2.

Control Range 0.004 to 1.5 in. of W.C. (0.996 to 373.5 Pa) Over Pressure

Withstand Accuracy Sensor Type Self-calibrating flow sensor (differential pressure).

Tu bing Connections

Tubing Length 5 ft (1.52 m) maximum, each tube.

Input Characteristics

±20 in. of W.C. (4.980 kPa) ±5% at 1.00 in. of W.C. (249.00 Pa) with laminar flow at

77 °F (25 °C) and suitable flow station.

Barb fittings for 0.170 in. I.D. (4.3 mm I.D.) FRPE polyethylene tubing or 0.25 in. O.D./0.125 in. I.D. (6.4 mm O.D./3.2 mm I.D.) Tygon taps).

tubing (high and low pressure

I/A Series BACnet Hardware

MicroNet Digital Wall Sensors

Each MicroNet BACnet controller supports a single MN-Sx digital wall sensor. 12 sensor models are presently available, six sensing zone temperature and six sensing both zone temperature and humidity. These range from a sensor-only model to one with seven pushbuttons and an LCD screen. Table–1.16 provides a feature summary of the MN-Sx sensors.

Note: S-Link communications is not supported in the MNB-1000-15 remote I/O module.

T able–1.16 MicroNet Sensors.

Sensor Model Features Sensor Model Features

MN-S1

MN-S1HT

MN-S2

MN-S2HT

MN-S3

MN-S3HT

MN-S4-FCS

MN-S4HT-FCS

No buttons

• Sensor only. Its primary function is to provide room temperature or humidity sensing values to the controller via the Sensor Link.

Three buttons

• MN-S2 features—Sensor; Override key with LED indicator.

• 3-digit LCD for showing (typically) the current temperature.

• Up and Down keys to allow adjustment of the current setpoint.

Six buttons

• Larger LCD capable of showing up to four possible temperature, humidity, and function displays

• Up and Down keys for setpoint adjustment.

• Three fan speed selection keys: – High Fan Speed – Medium Fan Speed – Low Fan Speed

• Fan On / Off / Auto key.

MN-S4

MN-S4HT

MN-S5

MN-S5HT

One button

• Sensor (as in MN-S1).

• Override key with LED indicator, to allow the timed override of unoccupied to occupied modes of operation.

Six buttons

• MN-S3 features—Sensor; Override key with LED indicator; LCD temperature, humidity, and function display (larger than in MN-S3, capable of showing up to four possible displays); Up and Down keys for setpoint adjustment.

• These “sub-base” functions: – Mode key allowing two

Heat/Cool/Auto/Off modes.

– Fan key to control fan operation or

speed.

– Setpoint key to select up to four

Heat/Cool setpoints.

Seven buttons

• MN-S4 features—Sensor; Override key with LED indicator; larger LCD capable of showing up to four possible temperature, humidity, and function displays; Up and Down keys for setpoint adjustment; Mode key, Fan key, and Setpoint key “sub-base” functions.

• Emergency Heat key with LED indicator for emergency heat activation or indication (Heat Pump applications).

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 21

Chapter 1

Figure–1.14 MN-Sx Sensor Pre-Wirable Baseplate and Electronic Assembly .

Common Sensor Features

An MN-Sx sensor communicates with (and is powere d by) two Sensor Link (S-Link) terminals on a MicroNet controller — it does not consume a typical I/O point. The S-Link connection between the sensor and the controller can use low-cost, twisted-pair wire up to 200 ft (61 m), and is not polarity sensitive. All MN-Sx sensor models also include an MS/TP jack for a convenient means of connecting a network tool, such as a Work Place Tech Tool PC, to the BACnet network.

Under each MN-Sx sensor’s detachable cover is a pre-wirable baseplate and a removable electronic assembly (Figure–1.14). The same baseplate is used in all MN-Sx sensor models.

Pre-wirable Sensor Baseplate

Removable Electronic

ssembly (contains

temperature sensor)

S-Link Screw Terminals (1 and 2)

MS/TP Jack

Note: MN-Sx sensors have no independent intelligence. This means any MN-Sx sensor’s behavior is defined by how the application control logic has been engineered, compiled, and downloaded into the MicroNet controller. This allows replacement of a sensor without need of additional programming.

Keypad Icons Depending on the sensor model used and the control application, various

keypad buttons allow the sensor user to select or perform dif ferent functions.

Table–1.17 MicroNet Sensor Keypad Icon Definitions.

Setpoint Override

Up Emergency Heat

Down Fan On/Off or Speed

Fan Speed (MN-S4-FCS) Hi,

Mode

Med, Low Fan On/Off Auto (MN-S4-FCS)

22 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

Figure–1.15 MN-S5 and MN-S5HT Keypad and LCD

(Most LCD Icons Shown Illuminated).

LCD Icons Sensor models featuring an LCD typically show the current zone

temperature as a default display. The MN-S4, MN-S4HT, MN-S5, and MN-S5HT models can also display selected icons, as shown in

(Table–1.18). These icons represent status items, depending on keypad

input and the current control application.

Table–1.18 MicroNet Sensor LCD Icon Definitions.

Degrees F Fan Cool

°F

Degrees C Fan Speed Hi On

°C

Diagnostic Functions

Relative Humidity Fan Speed Med Auto

AUTO

Outdoor Air Fan Speed Lo Off

Fan Heat Unoccupied

MN-S3, S3HT, S4, S4HT, S4-FCS, S4HT-FCS, S5, and S5HT sensors provide access to additional diagnostic data through the sensor keypad. This Diagnostic Mode data is displayed on the LCD screens of these sensors. See Figure–1.15 ( MN-S5 and MN-S5HT) and Figure–1.16 (MN-S4-FCS and MN-S4HT-FCS) for descriptions of the various elements of the keypad and LCD display.

LCD. The top area displays analog values, such as temperature and setpoints.

°F °C

The MN-S4, S4HT,

S5, and S5HT can show additional icons in this area.

AUTO

Up/Down buttons on MN-S3,

Setpoint, Mode, and Fan buttons on the MN-S4, S4HT, S5, and S5HT.

S3HT, S4, S4HT, S4-FCS, S4HT-FCS, S5, and S5HT are used to adjust setpoints and cycle through LCD icon displays.

Emergency Heat button and LED (MN-S5 and MN-S5HT only).

1 The icons displayed in the LCD are dependent upon the sensor model used,

the mode the controller is in, and the sensor's configuration in WP Tech. Not all icons are shown in this illustration.

Override button and Override LED. MN-S2, S2HT, S3, S3HT, S4, S4HT, S4-FCS, S4HT-FCS, S5, and S5HT have this feature.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 23

Chapter 1

AUTO

LCD. The top area displays analog values such as temperature, humidity, and setpoints.

Fan speed buttons, used to set High, Medium and Low speed.

The MN-S4-FCS and S4HT-FCS can show additional icons in this area.

Fan - On/Off Auto (optional) and Fan indication LED.

Up/Down buttons are used to adjust setpoints and cycle through LCD icon displays.

1 The icons displayed in the LCD are dependent upon the mode the controller is

in and the sensor's configuration in WP Tech. Not all icons are shown in the illustration.

Figure–1.16 MN-S4-FCS and MN-S4HT-FCS Keypad and LCD

(Most LCD Icons Shown Illuminated).

The LCD screen includes separate displays (frames) for the MicroNet controller’s:

• Subnet and Node Address

Note: Subnet will always display Ø (null), and the node address will reflect the address DIP switch setting.

• Errors–Not Supported

• Alarms–Not Supported

• Temperature and Relative Humidity Offsets

With the exception of the Temperature or Relative Humidity Offset, Diagnostic Mode data is view only. The Temperature or Relative Humidity Offset is adjustable and applies only to the integral temperature or humidity sensor in the MN-Sx sensor.

24 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

See the I/A Series MicroNet Sensors General Instructions, F-26277, for detailed information on the features and operation of MN-Sx sensors, including the Diagnostic Mode.

Communications Wiring

Communications wiring includes a connection between the controller and a MicroNet MN-Sx Sensor via the S-Link, and a connection between the controller and the MicroNet BACnet Network. Optionally, an MS/TP jack on the MN-Sx sensor allows a PC with a network tool, such as WP Tech, to be connected to the BACnet network.

Caution:

• Be sure to observe proper polarity when wiring the controller’s MS/TP

terminals to the MN-Sx Sensor’s wall plate. See Figure–1.13.

• To preserve the integrity of the network, the MS/TP network wiring

connecting a MicroNet BACnet controller to an MN-Sx sensor must be run to the sensor, then to the next controller, in daisy-chain fashion. A wire “spur” or “tee” must not be used to connect the sensor to the controller.

• Communication wire pairs must be dedicated to MN-Sx (S-Link) and

MicroNet BACnet network communications. They cannot be part of an active, bundled telephone trunk.

• When wiring the MNB-300 or MNB-1000 controller, or the MNB-1000-15

remote I/O module, provide enough strain relief (slack) in the wires to allow full range of movement for the input and output boards.

• Shielded cable is required for MS/TP network wiring and ADI or remote

I/O network wiring.

• Shielded cable is not required for S-Link wiring.

• If the cable is installed in areas of high RFI/EMI, the cable must be in

conduit.

• The cable’s shield must be connected to earth ground at one end only.

Shield must be continuous from one end of the trunk to the other.

I/A Series BACnet Hardware

Intermixing of Cables

Placing certain types of communications and power wiring in close pro ximity to each other can result in communications errors. To prevent this when running cables, you must note the combinations of wiring that may be intermixed and, when close placement is not recommended, ensure that there is sufficient separation between them. The combinations of wiring that are allowed to intermix are summarized in Table–1.19.

Note:

• The term, “intermix,” is used here to refer to the placement of wiring in

close proximity to each other. The pla cing of wirin g in the same conduit, or bundling the wiring together, are examples of extremely close placement.

• Observe the correct shielding of cables to prevent communications

problems such as those that may result from the intermixing of certain wiring types.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 25

Chapter 1

Table–1.19 Allowed Wiring Combinations for Int ermixin g

Wiring S-Link MS/TP

S-Link Yes Yes Yes Yes No No MS/TP Yes Yes Yes No Yes Yes ADI or Remote I/O Yes Yes Yes No Yes Yes UI, DI, UO Yes No No Yes No No DO No Yes Yes No Yes Yes Class 2 24 Vac No Yes Yes No Yes Yes

The following paragraphs detail the conditions under which wiring can be intermixed, including placement in the same conduit.

ADI or

Remote I/O

UI, DI, UO DO

Class 2

24 Vac

Sensor Link (S-Link) Wiring

Observe the following when laying S-Link wiring.

Note: Refer to Table–1.19 for a summary of the types of wiring that may be placed in close proximity to each other , such as when runn ing wiring through a common conduit.

• Do not intermix S-Link wiring with DO wiring or Class 2 AC power wiring,

especially in the same conduit.

• The S-Link wiring between an MN-Sx sensor and a MicroNet controller

can be intermixed with the ADI or remote I/O network wiring, or the MicroNet BACnet MS/TP wiring, including placement in the same conduit, so long as they are separate cables.

• S-Link wiring can be intermixed with UI, UO, and DI wiring, including its

placement in the same conduit.

MicroNet MS/TP Network Wiring

Observe the following when laying MicroNet MS/TP network wiring.

Note: Refer to Table–1.19 for a summary of the types of wiring that may be placed in close proximity to each other , such as when runn ing wiring through a common conduit.

• Do not intermix MS/TP wiring with UI, UO, or DI types of wiring.

• The MicroNet BACnet MS/TP wiring can be intermixed with the S-Link

wiring between an MN-Sx sensor and a MicroNet controller, including placement in the same conduit, so long as they are separate cables.

• The MicroNet BACnet MS/TP wiring can be intermixed with ADI or

remote I/O network wiring or DO wiring, including placement in th e same conduit, so long as they are separate cables.

• BACnet MS/TP network and Class 2 AC power wiring can be intermixed

(including placement in the same conduit), provided they are separate cables, and the MS/TP wire is properly shielded and meets the requirements stated in "Cable Specifications" on page 29.

26 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

ADI and Remote I/O Network Wiring

Observe the following when laying ADI or remote I/O network wiring.

Note: Refer to Table–1.19 for a summary of the types of wiring that may be placed in close proximity to each other , such as when running wiring through a common conduit.

• Do not intermix ADI or remote I/O network wiring with UI, UO, or DI

types of wiring.

• The ADI or remote I/O network wiring can be intermixed with the S-Link

wiring between an MN-Sx sensor and a MicroNet controller, including placement in the same conduit, so long as they are separate cables. Note that the MNB-1000-15 remote I/O module, itself, does not suppor t communications with an MN-Sx sensor.

• The ADI or remote I/O network wiring can be intermixed with MicroNet

BACnet MS/TP wiring or DO wiring, including placement in the same conduit, so long as they are separate cables.

• The ADI or remote I/O network wiring and Class 2 AC power wiring can

be intermixed (including placement in the same conduit), provided they are separate cables, and the ADI or remote I/O wire is properly shielded and meets the requirements stated in "Wiring Specifications for ADI or

Remote I/O" on page 31.

I/O Wiring

Observe the following when laying I/O wiring.

Note: Refer to Table–1.19 for a summary of the types of wiring that may be placed in close proximity to each other , such as when running wiring through a common conduit.

• Do not intermix UI, UO, or DI wiring with BACnet MS/TP wiring, ADI or

remote I/O network wiring, DO wiring, or Class 2 AC power wiring, especially placement in the same conduit.

• UI, UO, DI, and S-Link wiring can be intermixed, including placement in

the same conduit, so long as they are separate cables.

• Do not intermix DO wiring with S-Link wiring, especially placement in the

same conduit.

• DO wiring can be intermixed with BACnet MS/TP wiring, ADI or remote

I/O network wiring, or Class 2 AC power wiring, including placement in the same conduit, so long as they are separate cables.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 27

Chapter 1

Power Supply Wiring

Observe the following when laying Class 2, 24 Vac power supply wiring.

Note: Refer to Table–1.19 for a summary of the types of wiring that may be placed in close proximity to each other , such as when runn ing wiring through a common conduit.

• Do not intermix Class 2 AC power wiring with S-Link wiring or UI, UO, or

DI wiring, especially placement in the same conduit.

• Class 2 AC power wiring can be intermixed with BACnet MS/TP wiring,

ADI or remote I/O network wiring, or DO wiring, including placement in the same conduit, so long as they are separate cables.

Sensor Link (S-Link) Wiring

S-Link wiring powers and enables the MN-Sx sensor. The S-Link needs 24 gauge (0.51 mm) or larger, twisted pair, voice-grade telephone wire. The capacitance between conductors cann ot be more than 32 pF per foot (0.3 m). If shielded cable is used, the capacitance between any one conductor and the others, connected to the shield, cannot be more than 60 pF per foot (0.3 m). Maximum wire length is 200 ft. (61 m).

Note:

• Each MicroNet BACnet controller supports one MicroNet Sensor

(MN-Sx). Note, however , that the MNB-1000-15 r emote I/O module does not support communications with a MicroNet Sensor.

• S-Link wiring between the sensor and the controller is not polarity

sensitive.

• Refer to "Intermixing of Cables" on page 25 for a discussion of when

S-Link wiring may share conduit with other types of wiring.

28 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

MicroNet MS/TP Network Wiring

Caution:

• Before terminating the communications (MS/TP) wiring at the controller ,

test the wiring for the presence of a 24 Vac or 120 Vac voltage signal. If present, do not terminate the wiring at the controller’s MS/TP terminals. Doing so will damage the transceiver chip, rendering the controller unable to communicate. Instead, take corrective action before terminating the controller.

• Polarity must be observed for all MS/TP wiring within the MicroNet

BACnet network.

• The MS/TP cable’s shield must be connected to earth ground (GND) at

one end only, to prevent ground currents. Shield must be continuous from one end of the trunk to the other.

• To preserve the integrity of the network, the MS/TP network wiring

• Refer to "Intermixing of Cables" on page 25 for a discussion of when

BACnet MS/TP network wiring may share conduit with other types of wiring.

See Chapter 2, Networking Practices, to design a MicroNet BACnet network, including recommended topologies. Refer to Appendix A for

BACnet Best Practices.

Cable Specifications

Low capacitance cable is required for high baud rates and high controller counts. For this reason, all new installations should use a low-capacitance cable.

Note: Low-capacitance cables are not available in wire sizes la r ge r than 22 AWG (0.326 mm2).

Cable for wiring an I/A Series MS/TP network shall meet the following specifications:

• Use shielded, twisted-pair cable with characteristic impedance between

100 and 130 ohm. The shield may be either a foil- or braid-type, and should shield a single pair of conductors.

• Distributed capacitance between conductors shall be less than 15 pF/ft

(49 pF/m).

• Distributed capacitance between the conductors and the shield shall be

less than 30 pF/ft (98 pF/m).

• The maximum recommended length of an MS/TP segment is 4000 ft

(1200 m), using the cable s liste d in Table 1.20, on page 30.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 29

Chapter 1

Approved Cable Types

The stranded, twisted-pair cables listed in Table–1.20 are recommended for wiring a MicroNet BACnet MS/TP network.

T able–1.20 Recommended BACnet MS/TP Cable Types.

)

Plenum-

Rated

Yes

Capacitance @1 kHz Cond. DC

Cond-Cond Cond-Shield

22.0 pF/ft

(73 pF/m)

31.0 pF/ft

(103 pF/m)

25.0 pF/ft (83 pF/m)

11.4 pF/ft

(38 pF/m)

12.0 pF/ft (40 pF/m)

Baud Rate

19,200 or Less

76,800 or Less

a. The length of a wiring segment must be 4000 ft (1200 m) or less. b. Use plenum-rated cable for operating temperatures less than -4 °F (-20 °C).

No. of

Devices

32 Devices

128 Devices

or Less

Cable

Belden 8641

Belden 82641

Belden 82502

Connect-Air

W241P-2000F

Connect-Air

W241P-2000S

Belden 89841

AWG

(mm

(0.205)

Electrical Specifications

Resis. per

1000 ft

42.0 pF/ft

(140 pF/m)

59.0 pF/ft

(197 pF/m)

45.0 pF/ft

(150 pF/m)

n/a 27 ohm

22.0 pF/ft

(73 pF/m)

25 ohm

24 ohm

Oper.

Temp.

-4 to +176 °F

(-20 to +80 °C)

+32 to +140 °F

(-0 to +60 °C)

+32 to +140 °F

(-0 to +60 °C)

+302 °F max.

(+150 °C max.)

-94 to +392 °F

(-70 to +200 °C)

30 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

ADI and Remote I/O Module Network Wiring

Caution: Observe the following requirements for wiring between an MNB-1000 and an ADI panel or remote I/O module.

• Before terminating the wiring at the controller, test the wiring for the

presence of a 24 Vac or 120 Vac voltage signal. If present, do not terminate the wiring at the controller’s terminals used for the ADI or remote I/O network. Doing so will damage the transceiver chip, rendering the controller unable to communicate. Instead, t ake corrective action before terminating the controller.

• Polarity must be observed.

• The cable’s shield must be connected to earth ground (GND) at one end

only, to prevent ground currents. Shield must be continuous from one end of the trunk to the other.

• Refer to "Intermixing of Cables" on page 25 for a discussion of when

ADI or remote I/O module network wiring may share conduit with other

types of wiring.

See Chapter 2, Networking Practices, to design a MicroNet BACnet network, including recommended topologies. Refer to Appendix A for

BACnet Best Practices.

Wiring Specifications for ADI or Remote I/O

Wiring for an ADI or remote I/O module EIA-485 (formerly RS-485) network shall meet the following specifications:

• Use shielded, twisted-pair cable with characteristic impedance between

100 and 130

ohm.

• Distributed capacitance between conductors shall be less than 15 pF/ft

(49 pF/m).

• Distributed capacitance between the conductors and the shield shall be

less than 30 pF/ft (98 pF/m).

• Foil or braided shields are acceptable.

• The maximum recommended length of an ADI or remote I/O wiring

segment is 4000 ft (1200 m), using the cables listed for “76,800 or Less” baud rate in Table 1.20, on page 30.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 31

Chapter 1

I/O Wiring I/O connections include universal inputs, universal outputs, digital inputs,

and digital outputs. See Figure-1.1, Figure-1.2, Figure-1.3, Figure-1.5, and

Figure-1.6 for wire terminal information.

Caution: If shielded cable is used, connect only one end of the shield to the common terminal at the controller.

Universal Inputs (UI), Universal Outputs (UO), and Digital Inputs (DI)

Caution:

• Input and output devices cannot share common wiring. Each connected

device requires a separate signal and return conductor.

• Refer to "Intermixing of Cables" on page 25 for a discussion of when UI,

UO, and DI wiring may share conduit with other types of wiring.

Note: If maximum closed switch voltage is not more than 1.0 V and minimum open switch voltage is at least 4.5 V, then solid state switches may be used for a UI or a DI.

UI, UO, and DI wiring needs at least AWG #24 (0.205 mm

), twisted pair, voice grade telephone wire. The capacit ance between conductors canno t be more than 32 pF per foot (0.3 m). If shielded cable is used, the capacitance between any one conductor and the others, connected to the shield, cannot be more than 60 pF per foot (0.3 m). Table–1.21 provides wiring specifications.

Tabl e–1.21 UI, UO, and DI Wiring S pecifications.

Connection

UI, UO, and DI

Gauge

AWG (mm

18 (0.823) 300 (91) 20 (0.518) 200 (61) 22 (0.326) 125 (38) 24 (0.205) 75 (23)

)

Maximum Distance

ft (m)

Refer to Figure–1.7, Figure–1.8, and Figure–1.9, respectively, for examples of UI, UO, and DI connections.

32 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

Figure–1.17 MNB-300, MNB-1000, and MNB-1000-15—Sharing Common

Transformer Between DO Loads and Controller Power.

Digital Outputs (DO)

Caution:

• The Triac (digital) outputs on MicroNet BACnet controllers are not

rotected against short circuits. Take necessary precautions to pr

ese outputs against short circuits.

otect

• DO termina l s ac cep t up to on e AWG #14 (2.08 mm2 ) or two AWG #18

(0.823 mm2) or smaller wires. The selected wire gauge must be consistent with the load current rating.

• MicroNet BACnet controllers are Class 2 devices. Each digital (Triac)

output on an MNB-300 controller , MNB-1000 controller , or MNB-1000r

emote I/O module can support up to 12 VA at 24 Vac, 50/60 Hz, pilo

uty. On MNB-V2 and MNB-70 controllers, digital (Triac) outputs DO1

d plus DO2 can support a combined total of 24 VA at 24 Vac, 50/60 H p

ilot duty, while DO3 can support up to 12 VA.

• Refer to "Intermixing of Cables" on page 25 for a discussion of when DO

wiring may share conduit with other types of wiring.

If the transformer is sized correctly , the 24 Vac Class 2 power source may be used for load power. See Figure–1.17 for a diagram showing this with an MNB-300, MNB-1000, or MNB-1000-15.

Note: With the MNB-V2 and MNB-70, AC voltage to Triacs is sourced from the controller. This is different from the MNB-300 and MNB-1000 controllers and the MNB-1000-15 remote I/O module, where AC voltage is sourced externally . Refer to Figure–1.10 and Figure–1.11 for examples of Triac (DO) connections.

24 H

24 G

GND

24 VacPrimary

Class 2

Transformer

Load1

Load2

Loadx

TO1

TO2

TOx

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 33

Chapter 1

Power Supply Wiring

Ensure that MNB-70, MNB-300, and MNB-Vx controllers and the MNB-1000-15 remote I/O module have appropriate 24 Vac power, taking note of the following cautions.

Caution:

• Very important! When powering multiple Class 2 devices from the

same Class 2 power transformer, polarity must be observed (24H connected to 24H, and 24G connected to 24G).

• MicroNet BACnet controllers and remote I/O module are Class 2-only

devices and must be connected to a Class 2 source. Class 2 circuits must not intermix with Class 1 circuits.

• The MNB-70, MNB-300, and MNB-Vx controllers and the MNB-1000-15

remote I/O module contain a non-isolated half-wave rectifier power supply and must not be powered by transformers used to power other devices containing non-isolated full-wave rectifier power supplies. Note that this precaution does not apply to the MNB-1000, whose IO are fully isolated from its power supply input. Therefore, an MNB-1000 can be powered with the same transformer used to power MNB-70, MNB-300, and MNB-Vx controllers and the MNB-1000-15 remote I/O module. Refer to EN-206, Guidelines for Powering Multiple Devices from a Common Transformer, F-26363, for detailed information.

• Use a Class 2 power transformer supplying a nominal 24 Vac, sized

appropriately for the controller (16 VA for MNB-300, 15 VA for MNB-70 and MNB-Vx, 50 VA for MNB-1000, and 16 VA for MNB-1000-15) plus the anticipated DO loads. The supply to the transformer must be provided with a breaker or disconnect. In European Community, transformer must conform to EN 60742 .

• The Class 2 power transformer may be used to power multiple Class 2

powered devices, provided that the transformer is properly sized to power all equipment simultaneously and all devices contain the same type of rectifier power supplies or internal isolation.

• The transformer frame must be grounded.

• Refer to "Intermixing of Cables" on page 25 for a discussion of when

Class 2 power wiring may share conduit with other types of wiring.

Where power is derived from a central transformer, ensure that transformer is appropriately sized for the required VA with adequate margin and that the power wiring length is minimized and the appropriate wire size utilized to minimize line drops. Adequate transformer power margin should be allowed so that fluctuations of the primary transformer voltage or fluctuations in the secondary loads do not cause low voltage power conditions as seen at the 24 Vac input to the controllers.

The MNB-xxxx series controllers contain circuitry that is designed to protect the integrity of the embedded flash memory under low-voltage or questionable input voltage conditions. In the event of a controller-perceived low-voltage condition, the controller will set a read-only flag and lock out all writes to memory, as well as turn off controller outputs. The read-only flag can be easily viewed from the WorkPlace Commissioning Tool (WPCT)

34 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

under the “Device Properties” and will indicate the controller status as “Operational, Read-Only. ” The Read-Only status can help serve as an indicator that the input voltage to the controller may be questionable.

Note: The MNB-1000-15 remote I/O module also features protection for its embedded flash memory . When a module detect s a low-voltage condition, or questionable input voltage conditions, it locks out all writes to memory and turns off its output s. However, because the remote I/O module is mapped as an extension of the MNB-1000 controller’s I/O points, not as a separate device, it does not set a read-only flag. Instead, the WPCT simply shows the module as offline, and all its inputs will be “NA.”

Attention should also be paid to the wire distance between the central transformer and the secondary loads, especially in the case of half-wave input devices like the MNB-70, MNB-V series and MNB-300 controllers and the MNB-1000-15 remote I/O module. With half-wave type input devices, significant AC input current spikes can occur during the positive half-cycle of the AC input. Large resistances due to the wire lengths can cause significa nt voltage drops as seen from the controller AC input. In extreme cases, the controller may enter the read-only mode at apparent AC volt ages ex ceeding 20 V ac due to the asymmetrical nature of the AC input volt age waveforms. In these cases, reducing the load on the transformer, reducing the wire length between the controller and the transformer, and using higher current rated wire will correct the problem.

Note:

• Power wiring terminals accept one AWG #14 (2.08 mm

AWG #18 ( 0.823 m m

) wires.

) or up to two

• Power wiring can be intermixed with DO wiring.

• Twisted or untwisted cable can be used for power wiring.

• To preserve the integrity of the network, the MS/TP network wiring

connecting a MicroNet BACnet controller to an MN-Sx sensor must be run to the sensor and back, in daisychain fashion. A wire “spur” must not be used to connect the sensor to the controller.

Figure-1.18, Figure-1.19, and Figure-1.20 are acceptable wiring

configurations.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 35

Chapter 1

To Rest of the Remote I/O Network

Primary

Black

White Green (Ground)

24 Vac Secondary Class 2

S-Link

MS/TP

24H

24G

GND

To Rest of the

MS/TP Network

MN-Sx Sensor

To Rest of the

MS/TP Network

Controller

MNB-70

MNB-300

MNB-1000

MNB-V1 MNB-V2

Remote I/O

Network

24H 24G GND

IO+

IO-

SLD

From MNB-1000

From

Transformer

From

Transformer

To Controller or Remote I/O Module

Remote I/O Module

MNB-1000-15

1 Optional connection provides local access to

the MS/TP network.

2 Ground the frame of the transformer to a

known ground.

3 S-Link is not supported in the MNB-1000-15

remote I/O module.

Figure–1.18 Single Controller or I/O Module Powered from a Separate Class 2 Power Source.

36 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

I/A Series BACnet Hardware

Primary

24 Vac Secondary Class 2

To Rest of the

MS/TP Network

To Rest of the

MS/TP Network

To Other

MNB-70, MNB-300,

MNB-1000, and MNB-Vx

Controllers

MNB-70

MNB-300

MNB-1000

MNB-V1 MNB-V2

MN-Sx Sensor

MS/TP

MNB-70

MNB-300

MNB-1000

MNB-V1 MNB-V2

MN-Sx Sensor

S-Link

MS/TP

MNB-1000

MS/TP

MNB-70

MNB-300

MNB-1000

MNB-V1 MNB-V2

MN-Sx Sensor

24H

24G

GND

24H

24G

GND

24H

24G

GND

Shield

Or to End-Of-Line

Resistor

SLD (SHLD)

MS- (MSTP-)

MS+ (MSTP+)

Shield

SLD (SHLD)

MS- (MSTP-)

MS+ (MSTP+)

Shield

Black

White Green (Ground)

EOL

MS/TP

IO+

IO-

SLD

24H

24G

GND

SLD (SHLD)

MS- (MSTP-)

MS+ (MSTP+)

SLD (SHLD)

MS- (MSTP-)

MS+ (MSTP+)

To Network of MNB-1000-15 Remote I/O Modules

1 Optional connection provides

local access to the MS/TP network.

2 Ground the frame of the

transformer to a known ground.

3 MS/TP shield must be tied to

ground (GND) at a single point only.

4 Tie the MS/TP shields together

at the sensor baseplate (there is no GND terminal at the sensor).

5 In MS/TP networks, a 120 ohm

±5% EOL resistor must be used at each end of line. In the case of an MNB-300 or MNB-1000, EOL jumpers are provided.

6 Do not use EOL resistors in

standalone applications that do not include MS/TP communications.

7 MS/TP shields must be

connected to the SLD (or SHLD) terminal of all MicroNet BACnet controllers.

8 Do not make an MS/TP

connection to the sensor at the end of chain unless an EOL resistor is used.

9 At least one set, and no more

than two sets, of network bias resistors must be present on each MS/TP network segment, preferably (but not required to be) in the middle of the segment. In MS/TP networks, this requires an MNB-300, MNB-1000, or UNC-520 with the appropriate jumper settings.

Note: Jumper-set MS/TP bias resistors are built into UNC-520s.

Figure–1.19 Multiple Controllers Powered from a Single Class 2 Power Source and

Sharing Communications in a BACnet MS/TP Segment.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 37

Chapter 1

E O

Primary

24 Vac Secondary Class 2

MNB-1000

Shield

Black

White Green (Ground)

MS/TP

IO+

IO-

SLD

24H

24G

GND

SLD (SHLD)

MS- (MSTP-)

MS+ (MSTP+)

24H

24G

GND

IO+ IOSLD

MNB-1000-15

24H

24G

GND

IO+ IOSLD

MNB-1000-15

24H

24G

GND

IO+ IOSLD

MNB-1000-15

To Other

MNB-70, MNB-300,

MNB-1000, and MNB-Vx

Controllers

To Other

MNB-70, MNB-300,

MNB-1000, and MNB-Vx

Controllers

To MNB-70, MNB-300, MNB-1000, or MNB-Vx Controller

Remote I/O

To Rest of the

MS/TP Network

To Rest of the

MS/TP Network

1 One to eight MNB-1000-15 remote I/O modules

may be connected to a remote I/O network.

2 Ground the frame of the transformer to a known

ground.

3 MS/TP or remote I/O shield must be tied to

ground (GND) at a single point only.

4 In remote I/O networks, the EOL resistor must

be set at each end of line. The MNB-1000 controller and the MNB-1000-15 module have a jumper-set remote I/O EOL resistor for this purpose.

5 MS/TP shields must be connected to the SLD

(or SHLD) terminal of all MicroNet BACnet controllers.

6 Remote I/O shields must be connected to the

SLD (or SHLD) terminals of the MNB-1000 controller and the MNB-1000-15 remote I/O module(s).

7 Bias for the remote I/O network is provided by

the permanently enabled, built-in bias resistors on the MNB-1000 controller. The jumper-set bias resistors located under the cover of the MNB-1000-15 remote I/O module are set to "disabled" at the factory, and must not be used for this purpose.

Figure–1.20 Multiple Controllers and Remote I/O Modules Powered from a Single Class 2 Power Source and

Sharing Communications in a Remote I/O Network.

38 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Chapter 2 Networking Practices

This chapter provides an overview of the BACnet protocol and, more specifically , it s implementation in the MicroNe t BACnet system. This chapter then explains how MicroNet BACnet controllers and sensors are configured for an MS/TP network. The topics covered include:

• Introduction to BACnet

• Architecture Overview

• MS/TP Network Configuration

• Remote I/O Network Configuration

• MS/TP Network Considerations

• Other Network Setup Considerations

• Network Setup Procedures

Introduction to BACnet

In BACnet systems, BACnet devices use BACnet objects to share data. To allow this sharing of data, a BACnet network must be properly configured. On a properly configured network, the BACnet protocol carries data and uses Ethernet, Internet Protocol (IP), and Master Slave Token Passing (MS/TP) for network communication. At the device level, MS/TP network trunks connect individual BACnet compliant controllers.

Refer to Appendix A, BACnet Best Practices, for detailed information related to BACnet.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 39

Chapter 2

Architecture Overview

Introduction As implemented in a TAC I/A Series MicroNet BACnet network, the BACnet

architecture uses one or more networking data link layers to allow communication among controllers and engineering tools. At the device level, Master Slave Token Passing (MS/TP) networks can be used to connect up to 127 MNB-70, MNB-300, or MNB-Vx controllers, or MS/TP tools, to an MNB-1000 controller (see Table 2.1, on page 42). With 127 devices connected to an MNB-1000, all 128 MS/TP addresses on the MS/TP network are used. Similarly, up to 127 devices (MNB-70, MNB-300, MNB-Vx, MNB-1000, or MS/TP tools) can be connected to each network trunk of a UNC-520 or ENC-520 network controller, provided sufficient resources are available within the UNC or ENC (Table–2.1). Multiple BACnet MS/TP networks can be connected by networking the MNB-1000s and UNC/ENCs, using BACnet over IP or BACnet over Ethernet. This is referred to as a BACnet internetwork. In such a configuration, the MNB-1000 s and/or UNC/ENCs manage communication throughout the internetwork and serve as routers. Engineering tools can be used to manage controllers throughout an internetwork by connecting them to an MS/TP network trunk or by connecting to the IP network.

Figure-2.1 shows how a BACnet internetwork is comprised of four or five

individual networks. There are three individual MS/TP network trunks, each managed by a UNC/ENC or MNB-1000 and running individual BACnet devices. Ethernet or IP can be used as the networking technology for the backbone, adding a fourth network. If appropriate for the installation, both Ethernet and IP can be used on the network backbone. This would add a fifth network to the internetwork as shown in Figure–2.1.

40 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Internetwork

MSTP Network Trunk

S-Link Sensor

Ethernet and/or IP Backbone

MicroNet BACnet

MNB-300

Unitary Controller

MicroNet BACnet

MNB-V1 or V2 VAV Controller

MicroNet BACnet MNB-V1 or V2 VAV Controller

MicroNet BACnet

MNB-70

Zone Controller

Notebook PC with WorkPlace Tech Tool Software Suite

BACnet MS/TP Comm Bus

Optional Port Bridging to Additional MNB-1000 Controllers

MicroNet BACnet MNB-V1 or V2 VAV Controller

S-Link Sensor

A O

MicroNet BACnet MNB-70 Zone Controller

S-Link Sensor

MicroNet BACnet MNB-70 Zone Controller

S-Link Sensor

MicroNet BACnet MNB-300 Unitary Controller

S-Link Sensor

BACnet MS/TP Communications Bus

BACnet Router:

MicroNet BACnet MNB-1000 Plant Controller

MicroNet BACnet

MNB-1000

Plant Controller

MicroNet BACnet MNB-1000-15 Remote I/O Modules

Remote I/O Communications

PC Workstation with WorkPlace Tech Tool Suite

BACnet Router:

I/A Series Network Controller

Figure–2.1 BACnet Internetwork

Networking Practices

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 41

Chapter 2

MS/TP Network Configuration

The basic TAC I/A Series BACnet configuration is shown in Figure–2.1. Observe the following networking guidelines, for best operation on your BACnet MS/TP network trunks.

Physical Limits Number of Connected Devices

According to EIA-485 Specification

128 devices (including the UNC/ENC-520 or MNB-1000) is the physical limit of a MicroNet BACnet MS/TP network trunk. This limitation comes from the EIA-485 (formerly RS-485) specification on which a BACnet MS/TP network is based. According to this specification, the electrical limit of EIA-485 networks is 32 unit loads per segment (between repeaters), based upon the loading characteristics of the devices on that segment. However, because the UNC/ENC-520 and MicroNet BACnet controllers all use 1/4-load transceivers, four of these devices would together equal one unit load. Therefore, the actual electrical limit of an MS/TP network trunk comprised of a UNC/ENC-520 or MNB-1000, plus the MicroNet BACnet controllers connected to it, is 4 times 32, or 128 total devices.

Note: In terms of the EIA-485 standard, a unit load is based upon a device that has a EIA-485 transceiver whose load ef fect is 12 kilohm. The design of the EIA-485 transceiver on MicroNet BACnet controllers results in a load effect of 48 kilohm, thus making these controllers 1/4-load devices.

Maximum Number of Devices

Table–2.1 lists the physical limit on the numbe r of de vic es th at can be

connected to an MNB-1000, a UNC-520, or an ENC-520.

Table–2.1 Maximum Number of Connected Devices on MS/TP Trunk.

MicroNet BACnet

Router

MNB-1000 1127

UNC-520 4508 ENC-520 4508

Note: The physical limit on the number of connected device s sh own in

Table–2.1 does not mean that a UNC-520, an ENC-520, or an MNB-1000

can effectively support that number of devices. There are many logical factors that can further limit that number. Refer to Logical Limits, below.

Maximum Number of

MS/TP Connections

Physical Limit of

Connected Devices

(not including router)

Logical Limits Addressing Limit

The addressing of an MS/TP network trunk is limited to 256 addresses, numbered 0 to 255. Master devices are restricted to the first 128 addresses (0 to 127), while slave devices may use any address from 0 to 255. Because all UNC/ENC-520s and MicroNet BACnet controllers on an MS/TP network

42 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Networking Practices

trunk are master devices, they must be addressed with the first 128 addresses. As such, the address limit is the same as the physical limit of an MS/TP network trunk.

Limits to Number of Polled Points

Methods for Limiting Polled Points

There are three means for limiting the number of polled points, as described below.

Note: For additional information related to limiting the number of polled points, refer to Appendix A, BACnet Best Practices.

PollOnDemand Containers: The first method uses PollOnDemand containers, which limit the polling to those points that are being queried by an active GxPage. This means the points are polled if the graphic is being viewed in a browser, otherwise they do not. Points that must be polled all of the time (such as schedules), and points that are being logged, do not qualify for use in PollOnDemand containers.

Number of Devices: The second method is to limit the number of connected devices, as fewer devices equals fewer polled points.

COV Subscription: The third method is to use COV subscription to create subscriptions that send notifications to the subscribing device, thereby limiting the overall number of polled points. COV subscription can be used for most points that support the Subscribe COV service. However, in the case of points whose values change quickly, be sure to set the change of state value appropriately, so that COV notifications are not sent more frequently than necessary. Refer to Appendix A, BACnet Best Practices for more information.

Note: The relationship between polled points and COV subscribed points is not always easy to define. In general, COV subscribed points would not be considered polled points. However, a UNC/ENC-520 station will poll any BACnet output or AV priority point, therefore these point types still count as polled points, even when they are configured as COV subscribed points.

Limits to Resources

Communications through UNC/ENC-520s is further limited by the availability of Java resources (resource count) and other resources, suc h as pro ce sso r and memory. A shortage of these resources will limit the devices on an MS/TP network to a number less than the physical limit. Exceeding the resource limit will negatively affect the UNC/ENC-520s, possibly causing poor performance and resets (of the UNC/ENCs).

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 43

Chapter 2

Connection to an MS/TP Network

There are two methods for connecting a PC or notebook computer running WorkPlace Commissioning Tool (WPCT) or WorkPlace T ech Tool (WP T ech)

5.x to an MS/TP network.

BACnet Ethernet or BACnet/IP

The preferred method is to connect the PC or notebook computer to a LAN connection, and use BACnet/IP to connect to the BACnet internetwork. The BACnet internetwork connection routes the BACnet messages to the BACnet MS/TP network, as needed, through BACnet routers (UNC/ENC-520s or MNB-1000s). BACnet Ethernet can also be used to connect to the BACnet internetwork, but communication speed will be slower.

Controller MS/TP Jack or Sensor S-Link Jack

The second method connects the PC or notebook computer directly to the MS/TP network, either at the MS/TP jack on a MicroNet BACnet controller, or at the MS/TP jack of an S-Link sensor, provided it is connected to the MS/TP trunk. This type of connection requires a USB-to-MS/TP converter or EIA-232-to-MS/TP converter, depending on the port used on the computer.

Caution: A notebook computer connected to the MS/TP jack on an S-Link Sensor creates a Tee connection into the daisy-chained MS/TP network trunk. To minimize disruption of MS/TP trunk communications, the cable connecting the notebook to the MS/TP trunk should be as short as possible.

Remote I/O Network Configuration

The basic TAC I/A Series BACnet configuration is shown in Figure–2.1 on

page 41. The system illustrated there includes a remote I/O network,

connected under an MNB-1000. A remote I/O network of one to eight MNB-1000-15 remote I/O modules can be connected to an MNB-1000 to greatly expand its I/O count.

Observe the following networking guidelines, for best operation on your remote I/O network.

Connections When connecting one or more MNB-1000-15 remote I/O modules to an

MNB-1000 controller, observe the following:

• Be sure to connect the remote I/O network wiring to the MNB-1000

controller’s remote I/O port, not the MS/TP port or the MS/TP jack (see

Figure–1.5 on page 12).

• No other types of devices other than MNB-1000-15 remote I/O modules

may be connected to a remote I/O network, including S-Link sensors, commissioning and maintenance tools such as the WorkPlace Tech Tool Suite, etc.

44 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Physical Limits Number of Connected Devices

Figure–2.2 DIP Switch Address Example.

Note: This example shows

the address set to "5."

18765432

Least

Significant

Bit (LSB)

Most Significant Bit (MSB)

DIP Switch for Addressing

Remote I/O Module

According to EIA-485 Specification

The remote I/O network is based on the same EIA-485 (formerly RS-485) specification as the MS/TP network. However, because the number of MNB-1000-15 remote I/O modules that are allowed to be connected to an MNB-1000 is limited to eight devices, there is no danger of exceeding the EIA-485 limit.

Maximum Number of Remote I/O Modules

A maximum of eight MNB-1000-15 remote I/O modules may be connected to an MNB-1000 controller.

Logical Limits Addressing Limit

Each remote I/O module is equipped with a DIP switch for setting its address on the remote I/O network (Figure–2.2). The addressing of a remote I/O network is limited to nine addresses, numbered 0 to 8. The MNB-1000 controller’s local I/O is already assigned the addr ess “0,” while the MNB-1000-15 modules are assigned addresses “1” through “8.”

Networking Practices

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 45

Use Table–2.2 to calculate the DIP switch value for remote I/O module addressing.

Table–2.2 DIP Switch Value for Remote I/O Modules

For example, when setting the address to 8, you would set switch number 4 (value=8) to ON, while leaving switches 1, 2, and 3 OFF. In another example, you would set the address to 7 by setting switch numbers 1, 2, and 3 to ON (value=1+2+4=7), while leaving switch 4 OFF.

Switch

Number

1 (LSB) 1 5 Always OFF

2 2 6 Always OFF 3 4 7 Always OFF 4 8 8 (MSB) Always OFF

Value to ad d

if switch is ON

Switch

Number

Value to add

if switch is ON

Chapter 2

Note:

• Addresses assigned to the remote I/O modules must be consecutive.

That is, no addresses may be missed or duplicated. They are also required to start with “1,” as enforced by WP Tec h. If ther e ar e on ly 2 modules connected, they must be addressed as “1” and “2.”

• The addresses assigned to the MNB-1000-15 remote I/O modules are used only within the remote I/O network. These modules are transparent to the MS/TP network to which the MNB-1000 is connected. For all intents and purposes, the controller and its modules can be viewed, simply, as an MNB-1000 controller with expanded I/O.

Increased I/O Count

The addition of MNB-1000-15 remote I/O modules can greatly increase the number of I/O points of an MNB-1000 controller. Therefore, when adding a remote I/O network to an MNB-1000, it is especially important to take into account the increased I/O count when taking steps to limit the number of polled points on an MS/TP network. Refer to "Limits to Number of Polled

Points" on page 43.

MS/TP Network Considerations

Master and Slave Devices

Physical Addressing

On a BACnet MS/TP network, MicroNet BACnet controllers operate as master devices only . Valid DIP switch settings for these master controllers are 0-127.

Each controller on an MS/TP network trunk is initially identified by a unique address. The physical address is defined by the network number of the MS/TP network trunk into which the controller is connected, plus the controller’s address, which is set with the DIP switch on the controller. Procedures for assigning an MS/TP network number to an MS/TP network trunk under the control of a UNC-520 are provided in the BACnet Integration

Reference. Similar procedures for an ENC-520 are provided in the NiagaraAX BACnet Guide and the NiagaraAX Networking and IT Guide.

Procedures for assigning an MS/TP network number to an MNB-1000 are found in the Commissioning Tool and Flow Balance Tool Users Guide, F-27358.

Required Configuration

The DIP switch must be set on every controller that is added to an MS/TP network trunk. This number must be unique on that particular MS/TP network trunk but can be used on another internetworked MS/TP network trunk. For example, referring to Figure–2.1, each of the three MS/TP network trunks shown could use the DIP switch setting of 5 (Figure–2.2).

However, the same address (DIP switch setting) cannot be used on two controllers that are on the same MS/TP network trunk. Note that the least significant bit on the DIP switch is switch 1, the left-most switch.

46 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Networking Practices

Use Table–2.3 to calculate the DIP switch value for physical addressing. Take, for example, that the address must be set to 16. To do so, you would set switch number 5 (value=16) to ON. If the address is to be set to 43, instead, you would set switches 1, 2, 4, and 6 to ON (value=1+2+8+32=43)

Table–2.3 DIP Switch Value for MS/TP Networks

Switch

Number

1 (LSB) 1 5 16

22 632 34 764 4 8 8 (MSB) Always OFF

Value to ad d

if switch is ON

Switch

Number

Value to add

if switch is ON

Caution: In order for communication to occur, a unique MS/TP physical address must be assigned to each controller on an MS/TP network trunk.

• Duplicate addresses on an MS/TP network trunk will result in erratic

behavior, lost tokens, and disrupted communication.

• There is no software tool that will identify duplicate addresses on an

MS/TP network trunk. Typically, if two controllers are set to the same address, one of the controllers will appear to be missing from the list, and the address shared by the two controllers will intermittently come and go from the list.

• Be sure a netw or k w irin g dia gr am is used to assig n an d re co rd

addresses assigned to the controllers.

Optimization

MS/TP relies on a communication token that is passed among all ma ster devices on an MS/TP network. Starting at address 0 (zero) the token is passed, sequentially, to each device on the MS/TP network trunk until it reaches the device with the greatest address (i.e. Max Master, explained later in this paragraph). The token then st arts again at ad dress 0 and repeat s the cycle. A controller will attempt to pass the token to the address that is one greater than its own. If no device occupies that address, the sending controller tries the next address. It continues searching sequential addresses until it finds a device to accept the token. For each faile d pass there is a slight delay. Multiple gaps in the sequential addressing can result in increased communication overhead and decreased network efficiency. Therefore, addresses should be a contiguous set. Later, using the WPCT, a value will be set to indicate the greatest valid address on the MS/TP network trunk. This value is called Max Master . It prevents devices from searching for valid addresses beyond the greatest valid address. Additional optimization can be performed later by using the WPCT. Refer to: Appendix A, BACnet

Best Practices and the WorkPlace Tech Tool Release Notes, which is

provided with WorkPlace Tech and is also available in Tech Zone at The Source (http://source.tac.com/).

MS/TP Address for BACnet Tools

A BACnet tool, connected to an MS/TP network, requires a physical address for token passing. Leave one address unused, so that it is available for use by a BACnet tool.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 47

Chapter 2

Ethernet and/or IP Backbone

A O

Optional Port Bridging to One or Two Additional MNB-1000 Controllers

3 4 5

1 Up to 127 controllers can be attached to each trunk of a

UNC-520 or ENC-520 network controller, provided there are sufficient resources available within the device.

2 Only one MNB-1000, UNC-520, or ENC-520 may be configured

to route between any two BACnet networks.

3 MNB-1000 configured for routing to MS/TP network trunks and

optionally, between Ethernet and IP.

4 A high degree of communications performance may not be

possible if more than one, or possibly two, MNB-1000 controllers are placed downstream of a bridge. Therefore, no more than three MNB-1000 controllers should be bridged together.

5 Up to 127 controllers can be attached to an MNB-1000.

6 MNB-1000 not configured for routing.

7 MS/TP trunks are daisy-chained.

8 A notebook connection to a controller or the MS/TP jack

of an S-Link Sensor is a Tee. It must be as short as possible to preserve network integrity, and have its own unique address.

9 One to eight MNB-1000-15 remote I/O modules may be

connected to the remote I/O port of an MNB-1000. The MNB-1000-15 does not support S-Link.

Figure–2.3 BACnet Networking Restrictions

Other Network Setup Considerations

Figure–2.3 shows an IP network backbone and an Ethernet network

backbone plus thee MS/TP network trunks forming one BACnet internetwork. The network backbone can be Ethernet only, IP only, or both.

48 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Networking Practices

Figure–2.4 MNB-1000 Port Bridging.

Ethernet and/or IP Backbone

BACnet MS/TP Communications Bus

MicroNet BACnet MNB-1000 Plant Controller

Ethernet Port 0

Ethernet Port 1

3 3

5 5

112

3 6 3 6

1 The MNB-1000 contains two Ethernet ports: Port 0 (labeled

"0 Port) and Port 1 (labeled "1 Port").

2 The Ethernet port that is connected to the IP network will

operate at the rate implemented in that network (10 or 100 mbps).

3 When using port bridging, observe the following limitations:

• The maximum distance between MNB-1000 controllers is 300 ft.

• The throughput through the bridge is limited to 2.5 megabits.

• The throughput of the bridge is limited by the activity level of the MNB-1000 controller at any given time and the resources available to process the bridged data.

4 When port bridging, data is simply passed through an

MNB-1000 from one Ethernet port to the other. Neither port is designated as the "uplink" or "downlink" port. Therefore, either of the two Ethernet ports of an MNB-1000 may be connected to the IP network, and the other to an adjoining MNB-1000.

5 As a general rule, do not place any customer IT

devices such as computers or routers downstream of an MNB-1000 used as a bridge. Doing so may adversely affect the performance of such devices.

6 All devices being port-bridged to an MNB-1000 will

operate at the reduced rate of 2.5 mbps (see note 3). As a result, a high degree of communications performance may not be possible if one, or possibly two, MNB-1000 controllers are placed downstream of a bridge. Therefore, no more than three MNB-1000 controllers should be bridged together.

Port Bridging Beginning with Release 1.2, port bridging is enabled on the second Ethernet

port of the MNB-1000 controller. With port bridging, the MNB-1000 acts as a switch, where messages to and from the LAN are passed from the first Ethernet port to the second port (Figure–2.4). As such, port bridging is a convenient method for connecting additional MNB-1000 controllers.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 49

Chapter 2

IP Ethernet

Ethernet

Ethernet and IP Backbone

A second device must not be configured for both Ethernet and IP in a BACnet internetwork.

One MNB-1000 or I/A Series Network Controller can route between Ethernet and IP.

Figure–2.5 Incorrect Router Configuration

Single Path to Device

BACnet requires that there be no more than one communication path between two devices anywhere on the BACnet internetwork. More than one communication path between two devices results in a circular p ath. Normally this does not occur because the nature of a properly configured network does not allow multiple paths between devices. On a BACnet internetwork that uses both BACnet/IP and BACnet Ethernet, only one UNC/ENC or MNB-1000 in the internetwork may be configured to route between Ethernet and IP. If two or more devices are configured to route between BACnet Ethernet and BACnet/IP, multiple paths between controllers result.

In Figure–2.5 a UNC/ENC routes between BACnet/IP and BACnet Ethernet. It also routes MS/TP traffic for the BACnet trunk that is attached to it. The MNB-1000 routes BACnet Ethernet or BACnet/IP for the BACnet trunk that is attached to it. In this example, the MNB-1000 would be the se cond device configured to route between BACnet/IP and BACnet Ethernet, and this is not permitted. Allowing both the UNC/ENC and the MNB-1000 to serve as routers violates BACnet internetwork design requirements. This may cause intermittent communication failures, bandwidth problems, or the interruption of routing to MS/TP network trunks, as well as the shutdown of BACnet routing on the UNC/ENC (a self-protective feature).

Routers and Network Numbers

In a BACnet internetwork every network is assigned a unique network number. BACnet routers use the network numbers to route communication across the internetwork to individual controllers. The network numbers of all networks connected to a router must be entered into that router using the setup tool appropriate for the router. The WPCT is used to enter network numbers in an MNB-1000. In a UNC, WorkPlace Pro is used to enter network numbers, and Workbench is the tool used for this purpo se with the ENC.

50 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Networking Practices

Network Setup Procedures

The general procedures for setting up a BACnet network are described below. Follow these procedures to prepare a BACnet network trunk for logical addressing. After you complete these setup procedures, the WPCT can be used to configure logical addressing. For logical address configuration, refer to the Commissioning Tool and Flow Balance Tool Users Guide, F-27358.

Overview The general steps are listed below and detailed in the following sections.

1. Perform the physical installation of controllers and cabling.

2. Set the DIP switches on the controllers.

3. Power on the controllers.

4. Use WorkPlace Pro or Workbench to set BACnet service properties of the UNC/ENC.

Caution: Do not learn controllers until Step 6 has been completed.

This allows traffic to be routed to the MS/TP network trunk(s) att ached to the UNC/ENC and assigns logical addressing to the unit.

Physical Installation

5. Use the WPCT to commission the MNB-1000(s) that are connected directly to the backbone and used for routing, if applicable.

This allows traffic to be routed to the MS/TP network trunk that is attached to the MNB-1000, and assigns instance numbers to th e MNB-1000.

6. Use the WPCT to assign instance numbers to MNB-1000s that are not directly connected to the backbone, as well as MNB-70 controllers, MNB-300 controllers, and MNB-Vx controllers.

Install the cabling and controllers following the installation procedures in the Wiring Guidelines portion of this manual and the following guides:

• MicroNet BACnet MNB-70 Zone Controller Installation Instructions,

F-27456

• MicroNet BACnet MNB-300 Unitary Controller Installation Instructions,

F-27345

• MicroNet BACnet MNB-V1, MNB-V2 VAV Controllers Installation

Instructions, F-27346

• MicroNet BACnet MNB-1000 Plant Controller Installation Instructions,

F-27347

• MicroNet BACnet MNB-1000-15 Remote I/O Module Installation

Instructions, F-27486

• I/A Series UNC-520 Installation Instructions, F-27391

• I/A Series ENC-520 Installation Instructions, F-27416

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 51

Chapter 2

Set the DIP Switches on the Controllers

Power on the MNB-xxxx Devices

Commission UNCs and ENCs

Commission the Controllers

MS/TP Network

A DIP switch must be set on each MNB-70, MNB-300, MNB-1000, MNB-V1, and MNB-V2. The number must be unique on the MS/TP network trunk in which the controller is installed but can be repeated elsewhere on the BACnet internetwork. Refer to "Physical Addressing" on page 46. Follow the project’s wiring diagram to set the DIP switch on each controller.

Remote I/O Network

A DIP switch must be set on each MNB-1000-15 remote I/O module. Refer to "Addressing Limit" on page 45. Follow the project’s wiring diagram to set the DIP switch on each module.

Apply power to the MNB-xxxx devices, including all controllers and remote I/O modules. A status LED will illuminate on each controller or module, to show operation.

For UNC or ENC commissioning instructions, refer to the BACnet Integration Reference.

For WPCT details, refer to the Commissioning Tool and Flow Balance Tool Users Guide, F-27358. Controllers must be commissioned to interoperate with other BACnet devices. Any remote I/O modules, if present, will be commissioned together with the MNB-1000 controller to which they are connected.

52 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Chapter 3 Checkout and Troubleshooting

This chapter provides guidance for troubleshooting MicroNet BACnet controllers, sensors, and remote I/O modules, including:

• Mechanical Hardware Checkout

• Communications Hardware Checkout

Mechanical Hardware Checkout

Check out the mechanical hardware as follows:

MNB-Vx Controllers Only

1. Verify that both set screws are tightened to the damper shaft.

2. Press and hold the manual override button and rotate the da m pe r by turning the damper shaft. V erify that the damper moves freely between its fully open and fully closed positions.

All MNB Controllers

1. Verify that the wiring between the controller and the MicroNet Sensor is installed according to the job wiring diagram, and to national and local wiring codes.

Caution:

• Before terminating the communications (MS/TP) wiring at the controller ,

test the wiring for the presence of 24 Vac or 120 Vac. If present, do not terminate the wiring at the controller’s MS/TP terminals. Doing so will damage the transceiver chip, rendering the controller unable to communicate. Instead, take corrective action before terminating the controller.

• Polarity must be observed for all MS/TP wiring within the MicroNet

BACnet network.

• Polarity must be observed for all wiring on remote I/O networks.

• S-Link wiring between the sensor and the controller is not polarity

sensitive.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 53

Chapter 3

2. If the controller is part of a MicroNet BACnet network, verify that the MS/TP wiring between the controller and other devices is installed in accordance with the job wiring diagram, following national and local electrical codes.

3. Connect controllers in a MicroNet BACnet network in daisy-chain fashion. Be sure that MS/TP polarity, biasing, and termination are correctly implemented for each network segment.

4. Check for voltage at the COMM wires before setting termination at the controllers. Be sure voltage is not 24 to 120 Vac.

5. Verify that 24 Vac power is provided from a Class 2 power transformer, and that power wiring is installed in accordance with the job wiring diagram, following national and local electrical codes.

6. If multiple devices are powered from a common transformer, verify that all issues associated with powering multiple devices from a common transformer have been addressed. In particular , verify that wirin g polarity has been maintained between all connected devices (i.e. 24H connected to 24H and 24G connected to 24G).

Note: For more information, refer to EN-206, Guidelines for Powering Multiple Full-Wave and Half-Wave Rectifier Devices from a Common Transformer, F-26363.

7. Verify that digital outputs are wired according to the job wiring diagram, and with national and local electrical codes.

8. Make certain that electrical current requ irements of the controlled device do not exceed the rating of the controller’s digital outputs.

Caution: The digital outputs are not internally protected from ove r-c ur re n t or over-voltage conditions.

9. Make certain that the wiring between MNB-1000s and an y connected MNB-1000-15 remote I/O modules is correct.

Note: Connect MNB-1000-15s in a remote I/O network in daisy-chain fashion. Be sure that polarity, biasing, and termination are correctly implemented.

54 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Communications Hardware Checkout

XMT

STATUS

RCV

MNB-300

Unitary Controller

MNB-1000-15

Remote I/O Module

MNB-V1 / V2

Controller

STATUS MSTP RCV MSTP XMT

MNB-70

Controller

STATUS MSTP RCV MSTP XMT

MNB-1000

Plant Controller

STATUS

IO MSTP AUX

RCV

XMT

7 8

UO LEDs (3)

TO (DO) LEDs (6)

TO (DO) LEDs (8)

UO LEDs (8)

1 Bi-color status LED (all except

MNB-1000-15): green=good; red=fault; flashing red=bootloader mode.

2 Bi-color status LED (MNB-1000-15):

green=good; slow flashing green=not configured; fast flashing green=upgrading; slow flashing red=bootloader mode (normally 135 sec or less); steady red=not communicating; fast flashing red=firmware not compatible.

3 Green data transmission LED.

4 Amber data reception LED.

5 Red/green bi-color AppLED: Can be defined

in the device's application program. Off=0, Green=1, and Red=2.

6 Internal Triac Switches.

7 EOL and bias jumpers. Bias jumpers not

used in MNB-1000-15 (MNB-1000 provides bias for remote I/O network).

8 MNB-1000 includes EOL jumper for remote

I/O network.

Note: Components

are shown in their approximate locations.

Figure–3.1 Location of Controller LEDs and Jumpers.

See Figure–3.1 for the locations of controller LEDs and jumpers. Table–3.1 provides a guide for interpreting the LED indications.

Checkout and Troubleshooting

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 55

Chapter 3

Table–3.1 LED Indications.

Controllers &

Remote I/O Module

MNB-70

MNB-300

Status

XXX

MNB-V1, -V2

MNB-1000

Indicator Context Status

MNB-1000-15

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Power-up

Normal Operation

• Blinks red briefly then becomes solid green.

Indicates: A normal, healthy state.

• Blinks red during power-up, which takes 70 to 90 seconds to complete. When the power-up process successfully completes, the Status LED becomes solid green.

Indicates: Normal operation.

• Blinks red for a period of 2 minutes, then switches to solid red ON.

Indicates: Power-up process has failed. Controller fault.

• Solid green.

Indicates: A normal, healthy state.

• Solid red.

Indicates: A controller fault.

Wink Mode.

• Blinks red ON for 3 seconds, then OFF for 1 second, repeatedly for a period of 20 seconds (default).

• The MN-Sx sensor’s Override LED also blinks (all sensors except MN-S1 and MN-S1HT).

Indicates: Normal operation.

Wink Mode.

• Blinks red ON for 1 second, then OFF for 1 second, repeatedly for a period of 20 seconds (default).

• The MN-Sx sensor’s Override LED also blinks (all sensors except MN-S1 and MN-S1HT).

Indicates: Normal operation.

Corrective

Action

No action required.

Contact Schneider Electric Product Support.

No action required. Contact Schneider Electric

Product Support.

No action required.

56 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

T ab le–3.1 LED Indications. (Contin ued)

Controllers &

Remote I/O Module

Checkout and Troubleshooting

MNB-70

MNB-300

MNB-V1, -V2

MNB-1000

Status (Continued)

XXX

Indicator Context Status

MNB-1000-15

Bootloader Mode.

• Solid red ON at power-up.

Indicates: That the bootloader code is executing and the CRC test is either pending or has failed.

Status LED

Red/green

Status LED

Red/green

MN-Sx Sensor

Status LED

Red/green

Status LED

Red/green

Auxiliary LED

Red/green

After Flash Upgrade

Power-up

Cold Reset

Application Download

Firmware Upgrade

Normal Operation

• Blinks red ON for 1 second, then OFF for 1 second.

Indicates: The bootloader has passed the CRC test. Continues to repeat this pattern while the bootloader waits for a firmware upgrade or prepares for the jump to existing firmware.

Bootloader Mode.

• Continues to blink red beyond the initial 2 minute period during power-up.

Indicates: The motherboard is in the bootloader mode of operation, and is awaiting a firmware upgrade.

Cold Reset without Power Loss (commanded from the network management tool).

• MN-Sx sensor is shut OFF for 2 seconds, and then communication between the controller and the sensor is re-established.

Indicates: Normal operation. This allows the sensor to mimic the “reset without power loss” scenario.

• Normal controller function until download is completed.

• LED flashes red briefly following application download.

• Controller resets.

Indicates: Normal operation.

• Flashes ON red for 1 second, then OFF for 1 second, repeatedly for a period of 4 to 6 minutes following the file transfer from the PC to the controller.

Indicates: Normal operation.

• Red or green ON, or OFF, as programmed for the application.

Indicates: Normal operation.

Corrective

Action

No action required.

Take action as appropriate for the application.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 57

Chapter 3

T ab le–3.1 LED Indications. (Contin ued)

Controllers &

Remote I/O Module

MNB-70

MNB-300

Outputs

Remote I/O

MNB-V1, -V2

MNB-1000

Indicator Context Status

MNB-1000-15

Triac Output LEDs

Red

Universal Output LEDs

Red

Universal Output LEDs

Red

Status LED

Red/green

Input is Turned ON

Normal Operation

Power-up

• Solid ON when the respective input is turned ON.

Indicates: Normal operation.

• Illuminates in proportion to the output command signal, whether a load is attached or not.

Indicates: Normal operation.

• Illuminates in proportion to the output command signal, provided a proper load is attached to the output.

Indicates: Normal operation.

Note: Output LEDs on open circuit outputs will not illuminate.

Bootloader Mode.

• Flashes red slowly, beyond the initial 135 seconds, and then indefinitely.

Indicates: One of the following:

• The MNB-1000-15 remote I/O module is awaiting a firmware upgrade, or is in the middle of a firmware upgrade. Note: While the module is being upgraded, both the XMT and RCV LEDs will blink rapidly.

• The firmware is corrupted and the module can only stay in Bootloader mode.

Corrective

Action

No action required.

Wait for the upgrade of this or any other MNB-1000-15 module to occur and/or finish. If this state still exists several minutes after all other modules have been upgraded, do the following:

1) Check the wiring connection between the MNB-1000 and MNB-1000-15.

2) Check the address of the MNB-1000-15.

3) Disconnect the MNB-1000-15 module from the remote I/O trunk, reset the module, and then reconnect the module to the remote I/O trunk.

58 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

T ab le–3.1 LED Indications. (Contin ued)

Controllers &

Remote I/O Module

Checkout and Troubleshooting

Indicator Context Status

MNB-70

MNB-300

MNB-V1, -V2

MNB-1000

MNB-1000-15

Remote I/O (Continued)

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Status LED

Red/green

Power-up

Normal Operation

• Flashes red slowly for approx. 135 sec., and then becomes steady ON.

Indicates: The MNB-1000-15 remote I/O module has not received communications from an MNB-1000.

• Steady green ON as messages are received from the MNB-1000 and sent by the MNB-1000-15 remote I/O module.

Indicates: Normal operation. The module is healthy and is communicating with the MNB-1000 to which it is connected.

• Flashes green slowly.

Indicates: MNB-1000-15 remote I/O module has not been configured in the application. However, there is ongoing communication with the MNB-1000.

• Flashes green rapidly. XMT LED is actively flashing.

Indicates: The MNB-1000-15 remote I/O module is being upgraded.

• Flashes green rapidly. XMT LED is not actively flashing.

Indicates: The I/O modules have been set to an “Offline” state. The MNB-1000 is upgrading other MNB-1000-15’s on the bus.

Corrective

Action

1) Check the address setting at the MNB-1000-15’s DIP switch.

2) Check the wiring connection between the MNB-1000 and the MNB-1000-15.

3) Once the MNB-1000-15 has been correctly addressed and connected, the MNB-1000 will check the firmware level in the MNB-1000-15 and upgrade or downgrade it as necessary.

No action required.

Configure the MNB-1000-15, using the ADI/Remote IO Wizard. That is, in the application, connect at least one remote I/O hardware tag to control logic.

Wait for completion of the MNB-1000-15 upgrade process.

Wait for completion of the remote I/O module upgrade process.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 59

Chapter 3

T ab le–3.1 LED Indications. (Contin ued)

Controllers &

Remote I/O Module

Indicator Context Status

MNB-70

MNB-300

MNB-V1, -V2

MNB-1000

MNB-1000-15

Remote I/O (Continued)

Status LED

Red/green

Status LED

Red/green

Normal Operation

Power-up or Normal Operation

• Steady red ON.

Indicates: Normal communications interrupted between remote I/O module and the MNB-1000 to which it is connected. If fallback time has expired, the module will be in fallback mode.

• Flashes red rapidly.

Indicates: Remote I/O module is incompatible with MNB-1000 due to firmware version.

Corrective

Action

Restore communications. Check: remote I/O module wiring; remote I/O module addressing; and the connection to the MNB-1000.

Replace the MNB-1000-15 with a compatible unit, or upgrade its firmware to a compatible version.

60 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

T ab le–3.1 LED Indications. (Contin ued)

Controllers &

Remote I/O Module

Checkout and Troubleshooting

MNB-70

MNB-300

MNB-V1, -V2

MNB-1000

Communications

XXXX

Indicator Context Status

MNB-1000-15

• Flashes as messages are sent from

Transmit Data LED

Green

Receive Data LED

Amber

Receive Data LED

Amber

Transmit and Receive Data LEDs

Green and Amber

Ethernet 10/100 Link Integrity LED

Green

Ethernet 10/100 Activity LED

Amber

Normal Operation

the controller.

Indicates: Normal operation. The controller is healthy and is sending out a “Poll-for-Master” message.

• Flashes as messages are received from the network.

Indicates: Normal operation.

Note: This LED should remain OFF after disconnecting the MS/TP segment from the controller.

• Solid ON.

Indicates:

1. MS/TP+ shorted to SLD or GND on MS/TP network wiring.

2. Excessively heavy MS/TP traffic.

• LEDs behave erratically.

Indicates: Improperly biased MS/TP network segment.

• Solid ON.

Indicates: Normal operation. The link to the Ethernet PHY (physical layer transceiver) is good.

• Flashes ON for approximately 80 milliseconds each time there is receive or transmit activity.

Indicates: Normal operation.

Corrective

Action

No action required.

1. Check for shorted MS/TP+ to SLD or GND and make corrections as needed.

2. Verify network wiring integrity, polarity, and biasing, and make corrections as needed.

Ensure that network bias resistors are installed, and that EOL resistors are properly placed on the network segment daisy chain.

No action required.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 61

Chapter 3

Service Components within the MNB-70, MNB-300, MNB-V1, MNB-V2, and

MNB-1000 controllers cannot be field repaired. The MNB-1000-15 remote I/O module cannot be field-repaired, with exception of the units described in

Field-replaceable Units, below. If there is a problem with a controller or

module, follow the steps below before contacting Schneider Electric Product Support.

1. Make sure all controllers and modules are connected and communicating to the desired devices.

2. Check that all sensors and controlled devices are properly connected and responding correctly.

3. If a controller is operating, make sure the correct application is loaded, using Work Place Tech Tool (WP Tech). For more information, see the

WorkPlace Tech Tool 4.0 Engineering Guide, F-27254, and the WorkPlace Tech Tool BACnet Engineering Guide Supplement, F-27356.

4. Record the precise hardware setup, indicating the following:

• Version numbers of applications software.

• Controller or module firmware version number.

• Information regarding the WP Tech.

• A complete description of the difficulties encountered.

Field-replaceable Units

There are two field-replaceable part s ava ilable for th e MNB-1000-1 5 remote I/O module:

• MNB-CN TLR-15 Module Only

• MNB-BASE-15 Module Base

62 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Appendix A BACnet Best Practices

This appendix provides best practices information for creating and maintaining a network of MicroNet BACnet controllers and sensors, as well as a network of MNB-1000-15 remote I/O modules connected to an MNB-1000 controller. The material presented here is in addition to information already contained in Chapter 1, Chapter 2, and Chapter 3.

The information in this appendix has been acquired through factory testing and actual jobsite installations. The topics covered include:

• I/A Series MicroNet BACnet System Architecture Overview

• MS/TP Network Overview

• BACnet Rules that Must be Followed

• BACnet Best Practice Guidelines

• Remote Connectivity

• Performance Improvements for MS/TP

• Setting Up a Remote I/O Network

• Glossary

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 63

Appendix A

120 ohm EOL

Any MNB-xxxx Controller

PC Workstation or Laptop with WorkPlace Tech Tool Suite

USB

RS-485

Optional Serial

Connection

USB to RS-485

Serial Converter

PC (Web Browser)

I/A Series Server with Graphics Web Pages

BACnet MS/TP

BACnet Router:

MNB-1000 Plant Controller

BACnet MS/TP

120 ohm EOL

Remote I/O

Ethernet and/or IP Backbone

MNB-1000

MNB-1000-15 Remote I/O Modules

BACnet Router:

I/A Series Network Controller

120 ohm EOL

120 ohm EOL Jumper

7 8

1 Data values passed between the

network controller and the server.

2 Data values passed between the

MNB-1000 and the network controller, using BACnet/IP protocol.

3 Up to 127 MNB-xxxx controllers can be

attached to each trunk of a network controller, provided there are sufficient resources available within the device. Refer to Resource Limits-Additional Notes, in this section, for more information related to resource limits.

4 At least one set, and no more than two sets, of

network bias resistors must be present on each MS/TP network segment, preferably (but not required to be) in the middle of the segment. The MNB-300, MNB-1000, and TAC I/A Series Network Controllers have built-in, jumper-set network bias resistors for this purpose.

5 One to eight MNB-1000-15 remote I/O modules

may be connected to a remote I/O network.

6 In remote I/O networks, the EOL resistor must be

set at each end of line. The MNB-1000 controller and the MNB-1000-15 module have a jumper-set remote I/O EOL resistor for this purpose.

7 Bias for the remote I/O network is provided by the

permanently enabled, built-in bias resistor on the MNB-1000 controller. The jumper-set bias resistors located under the cover of the MNB-1000-15 remote I/O module are set to "disabled" at the factory, and must not be enabled for this purpose.

8 No other types of devices other than MNB-1000-15

remote I/O modules may be connected to a remote I/O network, including S-Link sensors, commissioning and maintenance tools such as the WorkPlace Tech Tool Suite, etc.

Figure–A.1 Typical System Architecture.

I/A Series MicroNet BACnet System Architecture Overview

64 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

Resource Limits—Additional Notes In addition to the resource limits noted in Figure–A.2, be sure to observe the

following:

• Integrating devices other than UNCs, ENCs, or MNB-xxxx controllers

may result in a different maximum number of devices.

• The maximum number of MS/TP devices allowed per MS/TP network is

limited to whichever is smallest among the following: 32 unit loads; the UNC or ENC resource limit; ENC CPU usage; or the UNC BACnet shadow object or ENC proxy point limit.

• All MNB-xxxx, UNC-xxx, and ENC-xxx devices use quarter-load

transceivers, which means that an MS/TP network comprised solely of MNB, UNC, and ENC devices can have no more than 128 total devices (32 X 4 = 128), consisting of one router plus 127 controllers. Refer to the definition of Unit Load in the “Glossary ” on page 109.

• A limit of 1500 applies to the UNC BACnet point shadow object and the

ENC proxy points. This limit refers to all BACnet point shadows and proxy points, regardless of type (MS/TP, BACnet/IP, or BACnet/Ethernet). Exceeding this limit will result in degraded performance.

• The UNC-520's resource limit is 600,000 Java Resource Units.

• The ENC-520's resource limit can be determined by comparing the

values for "heap.used" to "heap.max," found in the Resource Manager view of WorkBench. The value of "heap.used" should never be greater than 75% of "heap.max." For example, with a "heap.max" of 48MB, "heap.used" must not exceed 36MB.

Note: ENC-520 Resource Limit

An ENC-520’s resource limit can be calculated based on the “heap.max” and “heap.used” values, found in the Resource Manager view of Workbench, as shown in Figure–A.2.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 65

Appendix A

1 To determine the ENC-520's

resource limit, open the Resource Manager view, in Workbench.

2 Compare the value for "heap.used"

to "heap.max." The value of "heap.used" should never be greater than 75% of "heap.max." For example, with a "heap.max" of 48MB, "heap.used” must not exceed 36MB.

Figure–A.2 Finding Resource Limits of ENC-520.

66 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

MS/TP Network Overview

UNC-520 ENC-520

MNB-1000

Device

Address=0

MNB-xxxx

Controller

Device

Address=5

MNB-xxxx

Controller

Device

Address=4

MNB-xxxx

Controller

Device

Address=1

MNB-xxxx

Controller

Device

Address=3

MNB-xxxx

Controller

Device

Address=2

MNB-xxxx

Controller

Device

Address=X

MNB-xxxx

Controller

Device

Address=6

EOLEOL

1 The installing engineer or technician is free to choose the

locations of devices based on job requirements and other considerations. A device's address or controller type does not determine or restrict its physical location on a network segment.

For example, if a new device is to be added to an existing network and it is assigned the next available address, #16, it is perfectly acceptable to physically connect it to the network segment between devices #3 and #4, or #8 and #9, etc.

Note: Although the physical locations of devices are not important from an addressing point of view, be sure to observe note 2 regarding the presence of EOL resistors at each end of line.

2 A 120 ohm ±5% EOL resistor must be installed at

each end of line.

3 Although not required, in most systems the UNC,

ENC, or MNB-1000 is located at the end of line.

4 Additional devices, up to the highest-addressed

device connected to the UNC, ENC, or MNB-1000.

Figure–A.3 MS/TP Network.

BACnet Best Practices

Master-Slave T oken Passing

Devices on an MS/TP network communicate by means of Master-Slave Token Passing. In a typical MS/TP application, each controller (MNB-70, MNB-300, MNB-Vx, MNB-1000, UNC, or ENC) on the network is a master node on that network. As a master node, each device receives the communication token and then has the opportunity to eithe r send messages, or make requests, to other devices. In addition, each master controls the communication token while it is in its possession. See Figure–A.3 for an MS/TP network diagram.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 67

With the MaxMaster in all the devices on an MS/TP network set to the default value of 127, these devices will join the network and then automatically begin passing the token. Starting with the lowest-addressed device on the network (MNB-1000, UNC, or ENC), the token is passed to the next device, and from that device to the next, until it reaches the last device on the network. A device is determined to be the last one when either no device with a higher address can be found, or the devic e’s address equa ls the MaxMaster value. The last device then returns the token to the first device, to begin the cycle anew. This scenario is illlustrated in Figure–A.4, which shows the token being passed by all the master nodes.

Appendix A

Figure–A.4 MS/TP Network Token Passing.

Note:

• MaxMaster is a property that exists in all MS/TP master devices. This

property tells the device the highest MS/TP address that may exist on the network. The default value of this property is always 127.

• In an MS/TP network, a device can make requests and send COV

(Change of Value) data only during the time that it has the token.

• When a master device communicates with a slave device, it uses

request/response messaging. That is, the master requests an action, such as read or write, and then the slave responds with an action (answer).

UNC-520 ENC-520

MNB-1000

Device

MNB-xxxx

Controller

Device

Address=X

Other

Devices

1 As shown here, the token passing occurs as follows:

a. The token is started by the lowest-addressed

device. Typically this is the router, which is assigned address 0 (zero).

b. Device 0 makes any requests or responses, and

then passes the token to the next device, Device 1.

c. Device 1 makes any requests or responses,

including the sending of COV data, and then passes the token to the next device, Device 2.

d. Device 2 makes any requests or responses,

including the sending of COV data, and then passes the token to the next device, Device 3.

Address=0

MNB-xxxx

Controller

Device

Address=7

MNB-xxxx Controller

Device

Address=1

MNB-xxxx Controller

Device

Address=6

e. The token is passed in this way until it reaches the

last device on the network, Device X. A device is determined to be the last one when either no device with a higher address can be found, or the device’s address equals the MaxMaster value.

f. Device X, the last device on the network, then

returns the token to the first device, to repeat the token-passing cycle.

MNB-xxxx

Controller

Device

Address=2

MNB-xxxx

Controller

Device

Address=5

MNB-xxxx

Controller

Device

Address=3

MNB-xxxx

Controller

Device

Address=4

2 Additional devices, up to the highest-addressed device

connected to the UNC, ENC, or MNB-1000.

68 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

Device Addressing When an MS/TP network is configured, it is recommended that the UNC,

ENC, MNB-1000, or other routing device be assigned the first (lowest) address on the network, which is 0 (zero). For a UNC or ENC, this is also the default MS/TP address. As a best practice, other MS/TP devices (MNB-70, MNB-300, or MNB-Vx) that are added to the network should be addressed consecutively . In other words, no address numb ers should be skipped during the assigning process. The addressing should be 0 (routing device), 1, 2, 3, 4, and so forth, until the last (highest) address is reached.

BACnet Rules that Must be Followed

Although this appendix mainly focuses on best practices, the items listed in this section are mandatory and must be followed for any BACnet project.

General BACnet Rules

No Duplicate Device Instances

Device instances (device ID numbers) must not be duplicated anywhere on a BACnet network or internetwork. A device is known by its instance, and cannot be reliably located if it shares that instance with another device.

No Duplicate Object Identifiers within a Device

An object identifier is the combination of an object’s type and its instance number. No two objects of the same type within a BACnet device may have the same object identifier.

No Duplicate Network Numbers

Network numbers must not be duplicated anywhere on a BACnet internetwork. Duplicate network numbers will cause problems with BACnet routers and may disrupt communications.

Caution: Disruption of communications can affect the entire LAN. If you are using a shared network, be sure to coordinate with the LAN’s administrator, so as to minimize the effects of any nece ssary disruptions.

Devices on a Network Must Share a Single Network Number

A single site may have multiple BACnet networks, joined by one or more BACnet routers. While each of these networks must have a unique number, as stated above in "No Duplicate Network Numbers", each device on the same network must use the same network number. Generally, only one BACnet/IP network will exist on a site (or multiple sites connected with BBMDs). Therefore, all BACnet/IP devices on a site will have the same network number.

One Communication Path Only

There may be only one communications path between two devices. A duplicate route (circular path) will cause communications disruptions.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 69

Appendix A

Caution: Disruption of communications can affect the entire LAN. If you are

using a shared network, be sure to coordinate with the LAN’s administrator, so as to minimize the effects of any necessary disruptions.

One example of this is caused when two devices, a UNC (or ENC) and an MNB-1000, are set up to route to the same networks. This commonly occurs when a BACnet internetwork has a need for both BACnet/IP and BACnet/Ethernet networks. In this example, assume that the UNC (or ENC) is configured for both BACnet/IP and BACnet/Ethernet. Then, consider an MNB-1000 being configured to use BACnet/IP (without disabling BACnet/Ethernet), to route to the same networks as the UNC (or ENC). At this point, a circular path is created because both the UNC (or ENC) and the MNB-1000 will be configured for both BACnet/IP and BACnet/Ethernet. This occurred because MNB-1000s are configured to use BACnet/Ethernet, by default. This circular path could have been prevented by disabling BACnet/Ethernet on the MNB-1000 before activating BACnet/IP.

MS/TP Network Rules

The following items are mandatory for proper operation of an MS/TP network.

No Duplicate Addresses

The physical address must not be duplicated on any one MS/TP network. To avoid this problem, be sure a network wiring diagram is used when assigning and recording controller addresses.

Caution: Duplicate physical addresses on a single MS/TP network will disrupt communications on that network.

Note:

• The MS/TP address of an I/A Series MicroNet BACnet controller is set

with its DIP switch.

• A physical address may also be set in a non-physical manner, such as

with the communications configuration of a UNC, ENC, or WorkPlace Tech Tool (WP Tech).

• Any tool, including WP Tech, WPCT, WorkPlace Flow Balance Tool

(WPFBT) or other, that connects directly to the MS/TP network (not through a router) must also have a unique ad dr es s. If you r to ol ap pe a rs to be communicating but will not join the token passing, check for address conflicts.

Duplicate addresses on an MS/TP network trunk can cause many of the controllers on the network to stop communicating. The symptoms can include:

• If two controllers are set to the same physical address, the

communications token will either be lost or be generated twice, thus causing collisions.

• When two controllers are set to the same physical address, it will appear

that part of the network will be up and part will be down. That is, controllers will appear online, then offline, for no apparent reason.

70 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

Isolating the Problem

The only method to reliably identify multiple controllers with the same address is to physically check the DIP switch setting of each controller on the network. This task can be made easier by temporarily dividing the MS/TP network into smaller sections, so as to isolate the problem to a smaller area. In this way, not every device address will need to be verified.

Note:

• The duplicate MS/TP address cannot be determined by which

controllers are online or offline.

• While the WorkPlace Commissioning Tool (WPCT) will sometimes

detect multiple devices with the same address, there is no software tool that will reliably do so.

Install Terminators

Be sure to install or enable End of Line (EOL) resistors (120 ohm) as terminators on both ends of the MS/TP network. Failure to do so may result in intermittent communications. Terminating resistors are important because they help to reduce signal reflections and RF interference. Ensure that only two terminators are used, one at each end of the daisy-chained network. Using more than two terminators can excessively load the network and disrupt communications.

Make sure that the MNB-300 and MNB-1000 controllers’ EOL jumpers are set correctly. Having more than the two EOL resistors on an MS/TP network will cause intermittent communications. EOL resistors are physically set at the first and last devices (ends of line).

Note: For information on how the EOL jumpers on an MNB-1000 controller are used in a remote I/O network, refer to “EOL Resistors” on page 107.

Set Bias Resistors

As a requirement of EIA-485 network topology, an MS/TP network must have at least one set, and no more than two sets, of network bias resistors on each MS/TP network segment, preferably (but not required to be) in the middle of the segment. In MS/TP networks, this requires an MNB-300, MNB-1000, or UNC-520 with the appropriate jumper settings.

Note:

• Jumper-set MS/TP bias resistors are built into UNC-520s.

• For information on how the MNB-1000 provides bias to a remote I/O

network, refer to “Bias Resistors” on page 107.

A network of MNB-Vx controllers without a UNC-520, ENC-520, MNB-300, or MNB-1000 will not meet this requirement. This may commonly happen during installation before the router or area controller is installed. In this situation communications with devices may not be reliable.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 71

Appendix A

Use Proper Communication Cable

Wiring specifications become much more important as baud rates increase. In retrofit projects, you must be sure that the existing cable is suitable for reuse (meets specification). The use of cable that was specified for NETWORK 8000 ASD or MicroSmart cabling is acceptable if the baud rate is kept within the range of 9600 or 19.2 k. Upon moving up to a baud rate of

38.4 k or 76.8 k, the cable must meet the approved minimum specification for I/A Series MS/TP. Most ASD and MicroSmart cable will not meet this specification and cannot be used at the higher baud rates. Much of the cab le that has been used for previous installations may no t meet the specifications for the higher baud rate.

Be certain that the cable meets, or is lower than, the capacitance specification for MS/TP, and that it meets the nominal impedance range specified for MS/TP. See “MicroNet MS/TP Network Wiring” on page 29 for further information.

Bond the Shield to a Proper Ground

The shield conductor must be bonded to a known, good earth ground to dissipate any induced signals away from the communication cable. The shield wire should be continuous from one end to the other, with a bond to earth ground at only one location. For consistency, this should be done at the router (MNB-1000, UNC, or ENC). However, it may be done at some other place, if necessary, for a proper ground. If the bonding is not done at the router, be sure to document where it is done, for future reference.

Caution: Proper grounding of any EIA-485 shield circuit is important. While a weak ground may protect communications from low-frequency induced signals, such as from an AC power line, it is less likely to provide protection from higher frequency signals, such as radio frequency (RF) radiation.

72 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practice Guidelines

BACnet Best Practices

Selection of WP Tech Object

A WP Tech BACnet application may contain many BACnet supporting objects, and many WP Tech object types that represent them. Use care when selecting the BACnet object type to be used in a WP Tech application.

Type for BACnet

This section covers the WP Tech object types that directly represent BACnet supporting objects. You can find a description of these BACnet objects, as well as the supporting BACnet objects, in the WorkPlace Tech Tool BACnet Engineering Guide Supplement, F-27356.

T able–A.1 WP Tech Object Types and BACnet Supporting Objects.

WP Tech

Object Type

Analog Monitor AV Read Only n/a Used for reading application analog

Analog COV Client

Analog Setpoint AV R/W EEPROM Used for writing setpoint data to a

Analog Setpoint

Priority

Binary Monitor BV Read Only n/a Used for reading application bina ry

Binary COV Client

Binary Setpoint BV R/W EEPROM Used for writing setpoint data to a

Binary Setpoint

Priority

Command Priority

a.Niagara software cannot write the Relinquish Default value of Analog Setpoint Priority and Binary Setpoint Priority objects.

BACnet

Supporting

Object Type

AV Read Only

AV with priority array

BV Read Only

BV with priority array

AV or BV with priority array

Read Only or

Read/Write

(RW)?

(unless status is set “offline”)

R/W RAM, EEPROM

(unless status is set “offline”)

R/W RAM, EEPROM

R/W RAM Used to add a BACnet priority array to a

Write to RAM or

EEPROM?

values.

RAM Used for a peer-to-peer data passing

mechanism between controllers.

controller. This value is stored in EEPROM; use normal precautions to prevent damage to the EEPROM.

Used for writing any data to a controller

(for default only)

RAM Used for a peer-to-peer data passing

(for default only)

that may require the setting of a priority level. This object requires no precaution for memory type.

values.

mechanism between controllers.

controller. This value is stored in EEPROM; use normal precautions to prevent damage to the EEPROM.

Used for writing any data to a controller that may require the setting of a priority level. This object requires no precaution for memory type.

BACnet support object.

Usage

MS/TP Network Guidelines

Keep Exposed Communication Conductors Short

When terminating a communication cable for MS/TP (or any EIA-485 network), do not expose a long length of the conductors. Keep as much of the conductors covered by the cable shield (the aluminum wrap or wire mesh) as possible. Excessive exposed length can allow induced interference.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 73

Appendix A

Do Not Nick the Insulation When Removing the Cable Sheath

Most shielded, twisted pair (STP) cables have a small, high-strength cord between the sheath and the shield foil. This cord is inserted in the cable for use when tearing the sheath along the length of th e cable. A short tear at the end of the cable allows the sheath to be folded back so that the end of the sheath can be removed (cut off) without damaging the underlying insulation.

Make Low Resistance Terminations

Ensure that all terminations are low resistance. This can be done by simply:

• Tightening screw terminals.

• Making sure there is no insulation left on the wire where it terminates.

• Avoiding any terminations that are not at a normal place, such as a

controller.

• Carefully ensuring that a tight, low-resistance connection is made, with

very little exposed conductor, whenever a termination must be made between controllers.

Address Devices Consecutively

Number the MS/TP addresses consecutively. Gaps in addressing add delays in communications. Addressing should begin with node 0 (zero) and progress through all nodes, without any gaps, for each separate MS/TP network. It makes no difference where the device is physically located along the length of the network. Be certain that you start addressing with 0 (zero) and end at xx (the highest address), with no gaps in numbering between them.

A Router’s Address Should Be 0 (Zero)

The physical address of a router (UNC, ENC, or MNB-1000) or area controller on an MS/TP network should be 0 (zero) on that network. Although this is not a necessity, it should be followed for consistency, and because the device with the lowest (active) address will regenerate the communications token in the event of a lost token.

Few Controllers Per Network

Generally, performance is better with fewer controllers on an MS/TP network. This is because token passing on MS/TP networks can slow communications when a large number of controllers are on a single network. Therefore, it is better to have multiple, smaller MS/TP networks than one large network.

Use BACnet/IP for the MNB-1000

Whenever possible, it is better to communicate to an MNB-1000 via BACnet/IP rather than MS/TP. Both BACnet/IP and BACnet/Ethernet are much faster than MS/TP. In other words, if you are transferring point data from an MNB-1000 to a UNC or ENC, you should use BACnet/IP whenever possible.

74 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

Use Higher Baud Rates

Whenever possible, operate at the highest recommended baud rates on the MS/TP network.

Note:

• Note that the UNC-510-2 has a maximum baud rate of 19.2 k.

• The UNC-520-2, ENC-520-2, MNB-70, MNB-300, MNB-V1, MNB-V2,

and MNB-1000 have a maximum baud rate of 76.8 k.

Use Auto-baud to Change Baud Rate

Do not use the Device Properties dialog box in the WPCT to change the baud rate of an MNB controller unless you have been instructed to do so, or you are configuring an MNB-1000 MS/TP network for the first time. Instead, use the Auto-baud feature in WPCT to change the baud rates of MNB controllers. For instructions on using this feature, refer to the section on baud rate synchronization in the WorkPlace Commissioning Tool and Flow Balance Tool User's Guide, F-27358.

Changing the baud rate manually (outside of the automatic process) will likely result in controllers that are operating at different baud rates, and as a result, will not communicate with each other.

Add a Controller as MS/TP Slave After a Failed Upgrade

If an MNB-300, MNB-70, or MNB-Vx controller becomes stuck in boot-loader because of a failed upgrade, it may be added as an MS/TP slave, which would then allow you to restart the upgrade. An MNB-series controller that is stuck in boot-loader mode cannot Auto-baud, and so any communications will need to be at the same baud rate at which they failed.

Note: If the upgrade failed because of poor communications, be sure to fix the communications problem(s) first.

Power the Controllers Properly

Be sure that MNB-70, MNB-300, and MNB-Vx controllers, and any MNB-1000-15 remote I/O modules, have appropriate 24 Vac power. When power is supplied by a central transformer, be sure that:

• The transformer is appropriately sized for the required VA, with an

adequate margin.

• The length of the power wiring is minimized.

• The appropriate wire size is used, to minimize line drops.

An adequate transformer power margin should be allowed so that fluctuations in the primary transformer voltage or fluctuations in the secondary loads do not cause low-voltage power conditions at the 24 Vac input to the controllers.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 75

Appendix A

low-voltage condition, it will set a read-only flag and lock out all writes to memory, as well as turn off controller outputs. The r easily viewed in the Device Properties dialog of the WPCT, and will indicate the controller status as "Operational, Read- Only." The Read-Only status can help serve as an indicator that the input voltage to the controller may be questionable.

Attention should also be paid to the wire distance between the central transformer and the secondary loads, especially in the case of half-wave input devices like the MNB-Vx, MNB-70, and MNB-300 controllers and MNB-1000-15 modules. With half-wave type input devices, significant spikes in the AC input current can occur during the positive half-cycle of the AC input. Large resistances due to the wire lengths can cause significant voltage drops at the device’s AC input. In extreme cases, the controller or module may enter the read-only mode at apparent AC voltages exceeding 20 Vac, due to the asymmetrical nature of the AC input voltage waveforms. In these cases, reducing the load on the transformer, reducing the wire length between the controller or module and the tr ansfor mer, and using wire rated for higher current will correct the problem.

ead-only flag can be

Repeaters

Existing non-BACnet installations utilizing EIA-485 communications may contain repeaters. Generally, these will have been required when the network’s total length is over 4000 ft, or the device count is over 32. Existing repeaters in a non-BACnet system, such as those used with ASD networks, will not function with BACnet MS/TP. If you are converting a non-BACnet system to BACnet, and the network length exceeds 4000 ft, you can do either of the following:

• Use MS/TP repeaters such as Continuum™ b-Link Repeater

B-LINK-AC-S (RS-485) or B-LINK-F-AC-S (fiber optic)

• Divide the network into multiple, shorter MS/TP networks

If the BACnet system you are creating is part of a UUKL smoke control system, refer to details related to approved repeaters in the TAC I/A Series MicroNet BACnet Smoke Control Systems Manual, F-27419.

Set MaxInfoFrames to Value Greater Than 1

MaxInfoFrames is a property of MS/TP master devices. It determines how many read or write requests, and/or COV notifications, that a device can make before it must pass the token to the next device.

In a router device (or area controller), MaxInfoFrames should be set to a value that allows that device to make multiple requests of other devices before it passes the token to the next device. If the router’s MaxInfoFrames

76 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

is set at 1 (the usual default), the router may not be able to route efficiently to the MS/TP network. Testing has shown that increasing the value to 5 will result in a great boost in performance. Refer to Table–A.2 for recommended MaxInfoFrames values.

Table–A.2 Recommended Values for MaxInfoFrames.

Device

UNC 20 ENC 20 MNB-1000 as a router to MS/TP 20 MNB-1000 as an MS/TP only device 20 MNB-300 and MNB-Vx 3

MaxInfoFrames

Value

Set the MaxMaster Value

MaxMaster is a property of all MS/TP master devices. The default value of this property is always 127. MaxMaster tells the device what is the highest MS/TP address that may exist on the network. The following discussion explains why devices should be addressed consecutively on any MS/TP network.

Token passing is done by the controller holding the token, which gives it to the device with the next higher address. In turn, that device gives it to the device with the next higher address, and so on. When the token reaches the device with the highest address, that device passes the token back to the device with the lowest address, which starts the process anew.

A device knows that it is the highest addressed device in one of two ways. The first way is if its address matches its MaxMaster value. The second way is when the device cannot find another device with a higher ad dress to which it can pass the token.

To conserve communications bandwidth on an MS/TP network, a device that cannot find another device to pass the token to will initially ignore the missing device(s). However, a missing device cannot be ignored forever, so after a specified interval of 50 token passes, a poll for master service is initiated. In this process, the device polls consecutive addresses for the presence of any devices between its own address and its Ma xMaster val ue. If no such devices exist, the polling for nonexistent devices can waste a significant amount of time and data throughput. See the next section,

"Tuning the MaxMaster Pro perty", to improve performance.

Tuning the MaxMaster Property

To overcome some of the performance losses caused by the search for missing devices, as discussed above in "Set the MaxMaster Value", you may wish to tune the MaxMaster property. However, keep in mind that this will be a small performance gain and may not be of benefit unless your MS/TP network is heavily loaded, with much data p assing.

To tune the MaxMaster property, set it to a value that is just one or two higher than the highest address on the network. Do this for all controllers except address 0 (zero), which is as signed to the router or area controller. To be sure that the router or area controller can find any missing devices (for

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 77

Appendix A

example, if part of a network goes down) you must set its MaxMaster value to 127, which is the maximum number of controllers allowed on a network (and the maximum valid value for MaxMaster). The reason for setting the MaxMaster to a value greater than the highest address is to make sure that one or two unassigned addresses are available for a tool (WP Tech or WPCT) to join the network. That is, a device, including a tool, cannot join unless an empty address space is available.

Discussion of Joining Token Passing

Any device that is going to join the token passing of an MS/TP network must be passed the token before it can pass it on. If there is no activity, then the device can create a token. This has an imp act on adding new de vices, even temporary ones.

Note: A device may initially appear to be inactive when it is added to the network. This is normal, as it may take several seconds to join the token passing.

In the discussion of MaxMaster (see page 77), we learned that a device will periodically look for a missing or new device. The amount of time between these searches should be about 50 passes of the token. On a well-tuned and lightly loaded network, this will be quite frequent. On a degraded network, or one that is heavily loaded with many controllers, the token passing can be rather slow. How long could it take a new or missing device to join the token passing? If the time to complete one token pass cyc le is 1 second, and the device polls for master service after 50 passes of the token, the time to join could be anywhere from nearly 0 seconds, to 50 seconds. The length of time depends on how many token passes had occurred since the last poll for master when the de vice became active.

The information in this section is provided to help you understand why it can take a varying amount of time to connect WP Tech, WPCT, or WPFBT to an MS/TP network, using a serial adapter. If the token passing cycle is slow, it may take an excessively long time to join the network.

Understanding the Transmit and Receive Data LEDs on MS/TP Networks

Observation of a device’s transmit data ( XMT) and receive data (RCV) LEDs can be very helpful when troubleshooting certain situations on an MS/TP network. An understanding of the token passing sequences allows you to make some reasonable assumptions about how the network is performing.

78 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

Note: (See Figure–3.1 on page 55.)

• The XMT (transmit) LED on a UNC or ENC is amber, and the RCV

(receive) LED is green.

• The XMT LED on all MNB-xxxx series controllers and remote I/O

modules is green, and the RCV LED is amber .

• In EIA-485 (RS-485) communications (such as MS/TP), “TxD” and

“RxD” are traditionally used in reference to tran sm it an d re ce ive . However , the corresponding common terms, “XMT” and “RCV,” appear on the labels of some MNB-xxxx devices, and therefore will be used throughout this document.

In token passing on an MS/TP network, the token is passed from one controller to the next, in a cyclical manner. The token passing starts with the lowest-addressed device on the network, which passes the token to the next device. That device, in turn, passes it on to the next, and so on, until the token reaches the last device on the network, which then returns the token to the first device to begin the cycle anew.

Controllers

Because a device only transmits when it passes the token, makes a requ est, or responds to a request, it will be in receiving mode almost the entire time. For this reason, during normal token passing by most control device s, where there is not a great deal of point polling:

• The RCV LED will appear to be nearly solid ON but will flicker, and every

few seconds it will flash OFF.

• The XMT LED flashes (or flickers) in a fairly consistent pattern,

indicating the following:

– Each time the device receives the token and passes it on, the XMT

LED flashes once.

– Each time that a device receives a request (such as when it is polled

by a UNC or ENC), it will transmit a response and flash the XMT LED.

• The RCV LED should be ON except when the XMT is ON, or when any

device is performing a poll for master. Poll for master is an MS/TP means of finding devices that are not communicating.

Router or Area Controller

The normal LED flashing pattern for a router or area controller will basically be the same as with controllers, described above. However, it is possible that the device’s XMT LED will flash more frequently because it will be routing messages or making many requests. This means that, when compared to a controller, the RCV LED of a router will likely be flickering or flashing more, instead of appearing to be ON continuously.

Serial Converter

Normal flashing of the LEDs on a serial conver te r with a too l such as WPCT may be the same as described above, or the RCV and XMT LEDs may appear to be flashing about equally. This includes the B&B Electronics devices recommended for connection to MS/TP networks.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 79

Appendix A

In General

Generally, MS/TP communications problems are indicated as follows: XMT LED—Continuous Flashing, RCV LED—No Flashing: Any time the

XMT LED is flashing continuously, without any flashing from the RCV LED, we know that the device is trying to locate other devices by continuously polling for master but is receiving no responses. This lack of response is usually due to a wiring problem, or it may be that the ot her devices are no t at the same baud rate as the device being monitored.

RCV LED—Continuous Flashing, XMT LED—No Flashing: Any time that the RCV LED is flashing continuously, without any flashing from the XMT LED, we know that the device is not transmitting because it is not receiving the token. The cause is that the device is not receiving packets that it can understand, which may be due to a wiring problem, interference, or the wrong baud rate.

RCV LED—Mostly OFF: If the RCV LED is flashing, with or without the XMT LED, in a pattern where the RCV LED is off a good portion of the time, a serious wiring issue is present.

BACnet/IP Network Guidelines

Set the gateway address

If a BACnet/IP device is to communicate with devices that are not on its subnet, it must have a valid gateway address assigned to it. The gateway is the IP address of the network interface of the IP router (or switch) that connects this subnet to the rest of the LAN or W AN. Most UNCs, ENCs, and MNB-1000s that are enabled for BACnet/IP will need to have a gateway address. In general, if the network has more than one subnet, a gateway address will be needed.

Use BBMDs When Needed

BACnet protocol relies heavily on broadcast messages. This reliance on broadcast messages causes a serious issue for BACn et /IP, as routers and some switches will not pass broadcast messages. This very simply means that BACnet/IP broadcast messages will not travel from one subnet to another subnet. Instead, all BACnet broadcast messages will be stopped at the gateway to a subnet.

To work past this issue, a device called a BBMD was created that intercepts BACnet broadcast messages and then forwards them to BBMDs on other subnets.

Note: Only one BBMD may exist on an IP subnet containing BACnet/IP devices.

Exception—Foreign Devices: A special case in which a BBMD is not needed on a subnet is when a temporary device needs to communicate with a controller, but the device is on a remote subnet without a BBMD. An example of this is a tool such as the WPCT, which may need to temporarily communicate with a controller during commissioning. This scenario requires foreign device registration, which is a method of telling a BBMD that a device needs to communicate but will be leaving after a given amount of time. Foreign device registration works well for tools, but it will not work for most

80 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

controllers because most controllers are not designed to work as foreign devices. In other words, manually entering a controller in a UNC or ENC’s foreign device table (FDT) will not work.

BACnet/IP Through a NAT Router

BACnet/IP communications through a Network Address Translation (NAT) router will fail unless special provisions are made in the LAN’s firewall/NAT router . The reason for this is that a BACnet message contains the source address, which is the address of the device that sent the message. This source address is used by the destination device to send any responses back to the source. The NAT will cause that source address to be incorrect because of the address translation.

BACnet Ethernet Network Guidelines

BACnet/Ethernet is Not Routed

Ethernet messages are not routed through IP routers. This implies that BACnet/Ethernet should be used only on a single subnet. If BACnet messages must be sent from one subnet to another, consider using BACnet/IP with BBMDs, instead. See “Use BBMDs When Needed” on page

80.

An Exception: There is one exception to this. If the subnetting is accomplished using a managed switch, instead of a router, the switch may be configured to pass Ethernet messages. This could be a method used for spanning subnets with BACnet/Ethernet. However, the use of this method could cause problems if both BACnet/Ether ne t an d BACnet /IP ar e used on the same LAN. Plan carefully! Keep in mind that if this is a shared network, you will not have control of the switch or router, and may lose certain capabilities at anytime.

Do Not Leave BACnet/Ethernet Enabled if Not Used

When an MNB-1000 is configured as an MS/TP-only device, and does not use BACnet/IP or BACnet/Ethernet, you must be sure that BACnet/IP and BACnet/Ethernet are both disabled. Leaving BACnet/IP or BACnet/Ethernet enabled would mean that the MNB-1000 is still a router. This can create conditions under which the network is flooded with “Who is router to network” and “I am router to network” messages.

If a secondary means of accessing the MNB-1000 is needed, and you must have access through the Ethernet interface, it will be necessary to disable BACnet/Ethernet and enable BACnet/IP for each MNB-1000. In addition, each MNB-1000 will need to be on a separate BACnet/IP network, each with a separate UDP port.

BACnet Guidelines for UNCs and ENCs

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 81

Fewer Points Equals Better Performance

When using a UNC or ENC to communicate to a BACnet MS/TP network, it is important to recognize that minimizing traffic on the ne twork is the best way to achieving optimum performance. The number of active polled points significantly affects traffic on a BACnet MS/TP ne twork, and thus its throughput. The more traffic there is, the more significant its impact on performance.

Appendix A

In addition, there are limits to the number of objects a UNC or ENC can support. It is recommended that the device be limited to a total of 1500 point shadow objects (UNC) or proxy points (ENC). This quantity may be less, depending on the available resource count in the UNC or ENC.

While the total number of points can safely be 1500, the num ber of points that are polled at any given time should be fewer, for better performance. To limit this number, use PollOn Demand containers. See the following section.

Use Poll On Demand for Schedules, Alarms, and Trends

UNCs—Use PollOnDemand Containers

UNCs place all BACnet objects, when learned, into “poll always” containers. All objects other than those that need to be frequently updated (schedules, alarms, trended objects, etc.) should be moved to PollOnDemand cont ainers to minimize network traffic.

Note: Keep in mind that all containers that are not PollOnDemand containers are PollAlways containers, which will poll for values on a continuous basis.

ENCs—Do Not Add Point Extensions Unless Necessary

In ENCs, proxy points function in a "poll on de mand" manner when learned. However, when point extensions (alarm, history, or both) are added to a proxy point, the extension will cause the point to poll often. As a best practice, use proxy extensions only when necessary.

Delete Unused Points

Any BACnet objects that are learned in the UNC or ENC, but are not needed, should be deleted. Generally, all objects are learned during learning of a BACnet controller, and those not needed for contr ol or GxPages sh ould be deleted.

One method of doing this is:

1. Perform the learn of BACnet points.

2. Create a PollOnDemand container.

3. Give this container a name, such as “Holding” or “Store,” that will signify that it is used for storing shadow objects.

4. Move all of the point shadow objects into this container.

5. Do not link to any of the points in this cont ainer. Using this Po llOnDemand container to store BACnet objects will prevent unnecessary polling of values.

6. Create a second PollOnDemand container. Use this container for developing your graphics.

Note: PollOnDemand containers are usefull only with GxPages, because the point values are updated only when the GxPage is active.

82 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

7. Transfer the point shadow objects to the appropriate container as needed, noting that:

• Points for graphics go into a PollOnDemand container.

• Points that need to update continuously go into other containers.

8. Once the database is complete, simply delete the original PollOnDemand container named Holding or Store, if desired, and you will have cleaned up any unused points.

Keep the UNC or ENC Routing

A UNC or ENC will not tolerate networking configuration errors. If a UNC or ENC detects a duplicate route (a circular path), it will stop routing BACnet messages. When this happens, the station must be restarted to begin routing again. If the network error that caused routing to stop still exists, then routing will stop again, and the error must be investigated and corrected.

The behavior of the BACnet router can be changed in the ENC to keep routing enabled, by changing the property, [station]\Drivers\BacnetNetwork\ BacnetComm\Network\MaintainRoutingEnabled, to a value of True. However , the error that originally caused the routing to stop must be investigated and corrected.

The behavior of the BACnet router in a UNC with a BACnet module (jar file) of build bacnet-2.305.515a or later can be changed to keep routing enab led. Instructions for this may be found in the release notes for build r2.301.522.

Keep the Processor Idle Time Above 20%

At no time should the processor idle time be less than 20%. Allowing processor idle time to drop below 20% may have undesirable effects, including the loss of control functionality. A low idle time is certain to adversely affect communications of any type, including BACnet.

The most common cause of low processor idle time is an excessive number of program objects. As a general guideline, keep the number of program objects fewer than 100. Less is better. If program objects must be used, o ne way of reducing the quantity is to combine the functions of two or more program objects into one.

UNC and ENC Bias Resistors

Always keep in mind that each MS/TP network should have at least one set, but no more than two sets, of bias resistors. When using a UNC-520 or ENC-520, or one or more MNB-1000s, determine which device(s) will provide the bias resistors for the network and set the jumpers appropriately.

Use COV Subscription for Slowly Changing Points

The use of COV subscription at the UNC or ENC level has the potential to increase performance. Use COV for points that do not change value quickly. The frequency of updates can be controlled with the covIncrement property. Setting the COV increment to a larger value lessens the update freq uency, thus potentially improving performance.

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 83

Appendix A

Do Not Use COV for Priority Type Points

The UNC or ENC uses a “rewrite mechanism” to detect whether a point is at the value that the UNC or ENC last commanded. Priority type points stay in the poll queue even when they are COV subscribed. Due to this rewrite mechanism, priority points have the potential to increase update times in the UNC or ENC. The priority type points are: all outputs, analog value priority points, and binary value priority points. These points should be avoided for COV subscription.

Tuning Policy for ENC

Refer to the section, “About Tuning Policies,” in the Niagara AX-3.x User Guide for a discussion of tuning policies and recommendations that can be used to optimize the way write requests (to writable proxy points) and read requests are evaulated in ENCs.

General BACnet Guidelines

Consider Network Design Carefully

When designing BACnet networks and internetworks, keep the end result of a functioning system in mind. A simple MS/TP network is straight forward to design and install, but the complexity increases dramatically when ne two rks are joined together to form an internetwork. Proper planning and understanding of modern networking principles is desirable for creating a BACnet internetwork that includes IP and Ethernet routing and switching.

If a shared network is included in the design, close coordination with the facility’s IT department may be required. Making prior assumptions about an IT department’s capabilities, or their ability to cooperate, may be undesirable. Having your own staff trained in networking essentials will help considerably in working and communicating with the appropriate IT personnel.

Remote Connectivity

Remote connectivity is the need to access a BACnet device that exists on a network (or subnet) other than the one on which your tool’s PC resides. To accomplish remote access communications, we need to consider the following items.

Item One. Remote access requires a connection using a telecommunications interface, which can be a telephone line or a broadband Internet connection. The BACnet datalink layer type that can utilize these types of connections is BACnet/IP. This generally excludes all other BACnet connections.

Item Two. BACnet relies heavily on broadcast messages. Broadcast messages are generally not passed through IP routers, so special provisions must be made to transfer BACnet broadcasts from one network subnet to another. A special BACnet/IP device, called a BACnet Broadcast Management Device (BBMD), was created for the purpose of transferring broadcast messages from one subnet to another. The BBMD does this by transforming any BACnet broadcast messages (BACnet/IP, BACnet/Ethernet, or MS/TP) that it receives into unicast BACnet/IP messages that are directed to the other BBMDs on the BACnet inte rnetwork.

84 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

BACnet Best Practices

Item Three. BACnet/IP messages are not compatible with Network Address Translation (NAT). This means that if NAT is used (check with the IT department), it must be bypassed by some means.

Considering the above three items, we will use BACnet/IP for remote connectivity and make special provisions for its use.

Items necessary for BACnet/IP communications are:

• IP address

• Subnet mask

• UDP port number

• Unique but common network number

Additional items for BACnet/IP communications between subnets are:

• Gateway address

• One BBMD is needed, per subnet, with appropriate BDT entries

Additional items that may be required for off-site access are:

• Open the BACnet/IP UDP port on the firewall

• Configure a one-to-one NAT

Note:

• Any BACnet/IP communication that passes through a firewall may

require changes to the firewall settings. Make certain that the BACnet/IP UDP port is open. This includes any personal firewall software on a PC.

• The UDP port default is 47808 (0xBAC0). The UDP port only needs to

be changed if there is a network conflict. In other words, if IT personnel have instructed you to change it. Secondly, you may change the port if there is a need for two (or more) separate BACnet/IP networks on the same physical network media. In that case, each of these BACnet/IP networks would then be assigned separate networ k numbers, with e ach network using a separate UDP port.

BBMDs– Connecting BACnet/IP Devices on Different Subnets

F-27360-11 MicroNet BACnet Wiring, Networking, and Best Practices Guide 85

Each BBMD must hold the addresses of all other BBMDs that it will work with, in a table called the BACnet Distribution Table (BDT). When a BBMD receives a BACnet broadcast message (either a request or a response), it sends the message as a Forwarded-NPDU message to all other BBMDs in the BDT. When a BBMD receives a Forwarded-NPDU message from another BBMD, it broadcasts the message on its local networks (BACnet/IP, BACnet/Ethernet and MS/TP). Through these actions, the broadcast messages will be sent to all BACnet devices on the internetwork. See

Figure–A.5.

Secondly , BBMDs h old all addresses of temporary BACnet devices, such as a PC with WPCT, in a table called the Foreign Device T able (FDT). A foreign device is a BACnet/IP device with the capability of self-registering with a BBMD, to allow the BBMD to transfer broadcast messages to and from that foreign device. The foreign device registration is timed to expire automatically. To continue communicating, the foreign device must re-register shortly before the time expires. Fore ign device registration can be used for permanent devices, in case a BBMD is not available on the local subnet. However, the device must have the built-in capability of being a foreign device and must also be configured as such.

Appendix A

BACnet/IP

Device

IP = 10.1.137.43 Mask = 255.255.255.0 GW = 10.1.137.200

BBMD

IP = 10.1.137.6 Mask = 255.255.255.0 GW = 10.1.137.200

BACnet/IP

Device

IP = 10.1.137.17 Mask = 255.255.255.0 GW = 10.1.137.200

Subnet 10.1.137.0

BACnet/IP

Device

IP = 10.1.142.38 Mask = 255.255.255.0 GW = 10.1.142.200

BBMD

IP = 10.1.142.47 Mask = 255.255.255.0 GW = 10.1.142.200

BACnet/IP

Device

IP = 10.1.142.66 Mask = 255.255.255.0 GW = 10.1.142.200

Subnet 10.1.142.0

Subnet 10.1.144.0

Foreign Device

(Example: PC Workstation or Laptop with WorkPlace Tech Tool Suite)

IP = 10.1.144.91 Mask = 255.255.255.0 GW = 10.1.144.200

IP Router

Segregates the network into subnets. Each interface of the router becomes the gateway (GW) to a subnet.

10.1.144.200

10.1.142.200

10.1.137.200

Figure–A.5 Subnetted LAN with BACnet/IP.

In an IP network, each subnet that is to be part of the BACnet internetwork should have a BBMD. It is likewise important that only one BBMD exist per subnet, for a single BACnet/IP network. Having multiple BBMDs on the same subnet will flood the subnet with unnecessary IP traffic and greatly slow BACnet communications.

86 MicroNet BACnet Wiring, Networking, and Best Practices Guide F-27360-11

Schneider Electric TAC I/A Series Operating Instructions

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

Preface

Purpose of this Manual

Applicable Documentation

Related Documentation

Conventions Used in this Manual

Acrobat (PDF) Conventions

Contents, as well as cross-references within the body text. For ease of recognition, cross-reference links within the body text appear in blue type, for example Manual Summary. A link is indicated whenever the mouse pointer changes to a hand with a pointing finger.

Abbreviations and Terms Used in this Manual

MicroNet BACnet Controllers

Common Controller Features

BACnet Compliance

MNB-300 Unitary Controller

MNB-V1, MNB-V2 VAV Controllers

MNB-70 Zone Controllers

MNB-1000 Plant Controller

MNB-1000-15 Remote I/O Module

Input and Output Specifications

Universal Inputs

Universal Outputs

Digital Inputs

Digital Output s, Triac

20 Vdc Output

Inputs from MN-Sx MicroNet Sensor

Velocity Pressure Input

MicroNet Digital Wall Sensors

Common Sensor Features

Keypad Icons Depending on the sensor model used and the control application, various

LCD Icons Sensor models featuring an LCD typically show the current zone

Diagnostic Functions

Communications Wiring

Intermixing of Cables

Sensor Link (S-Link) Wiring

MicroNet MS/TP Network Wiring

ADI and Remote I/O Network Wiring

I/O Wiring

Power Supply Wiring

Sensor Link (S-Link) Wiring

MicroNet MS/TP Network Wiring

Cable Specifications

Approved Cable Types

ADI and Remote I/O Module Network Wiring

Wiring Specifications for ADI or Remote I/O

I/O Wiring I/O connections include universal inputs, universal outputs, digital inputs,

Power Supply Wiring

Introduction to BACnet

Architecture Overview

Introduction As implemented in a TAC I/A Series MicroNet BACnet network, the BACnet

MS/TP Network Configuration

Physical Limits Number of Connected Devices

Logical Limits Addressing Limit

Limits to Number of Polled Points

Limits to Resources

Connection to an MS/TP Network

Remote I/O Network Configuration

Connections When connecting one or more MNB-1000-15 remote I/O modules to an

Physical Limits Number of Connected Devices

Logical Limits Addressing Limit

Increased I/O Count

MS/TP Network Considerations

Master and Slave Devices

Physical Addressing

Required Configuration

Optimization

MS/TP Address for BACnet Tools

Other Network Setup Considerations

Port Bridging Beginning with Release 1.2, port bridging is enabled on the second Ethernet

Single Path to Device

Routers and Network Numbers

Network Setup Procedures

Overview The general steps are listed below and detailed in the following sections.

Physical Installation

Set the DIP Switches on the Controllers

Power on the MNB-xxxx Devices

Commission UNCs and ENCs

Commission the Controllers