Schneider Electric TAC Xenta 120 Technical Data

TAC Vista

TAC Pangaea

WorkStation

TAC Xenta 120

Technical Manual

TAC Vista

TAC Xenta 120

Technical Manual

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TAC Xenta, TAC Xenta 120 Contents

Contents

INTRODUCTION

1 About this Manual 11

1.1 Structure..................................................................................................................... 11

1.2 Typographic Conventions.......................................................................................... 12

1.3 Prerequisites............................................................................................................... 12

1.4 Terminology............................................................................................................... 13

GETTING STARTED

2 Planning the Project 19

2.1 Folder Structure.......................................................................................................... 19

2.1.1 Creating a Project Folder ........................................................................................... 19

2.2 Case Study.................................................................................................................. 20

2.2.1 Description of Facility................................................................................................ 20

2.2.2 Device Description and Naming Convention ............................................................ 21

2.2.3 Devices in the Example.............................................................................................. 22

2.2.4 Network Structure and Naming Convention in the Example..................................... 23

3 Creating the TAC Xenta 120 Configuration 25

3.1 ZBuilder Example Overview ..................................................................................... 25

3.2 Starting ZBuilder.......................................................................................... .... ..... ..... 25

3.3 Selecting a Template.................................................................................................. 26

3.4 Adjusting the Configuration....................................................................................... 26

3.4.1 Adjusting the Heating/Cooling Parameters................................................................ 27

3.4.2 Adjusting the Fan Parameters .................................................................................... 29

3.4.3 Adding a Room Unit.................................................................................................. 30

3.4.4 Adding an Occupancy Signal..................................................................................... 31

3.4.5 Adding a Window Contact......................................................................................... 32

3.4.6 Adjusting the Control Parameters for the Fan............................................................ 33

3.5 Specifying an Exception Mode.................................................................................. 34

3.6 Changing the Inputs/Outputs configuration............................................................... 35

3.7 Documenting and Saving the Configuration.............................................................. 37

3.7.1 Documenting the Configuration on a Printout........................................................... 37

3.7.2 Saving the Configuration File.................................................................................... 38

4 Installing TAC Xenta 120 in a Classic Network 39

4.1 Adding and Configuring the TAC Xenta 120............................................................ 39

4.1.1 Adding a LonWorks Group........................................................................................ 39

4.1.2 Adding a TAC Xenta 120 .......................................................................................... 40

4.1.3 Configuring a TAC Xenta 120................................................................................... 42

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Contents TAC Xenta, TAC Xenta 120

4.2 Commissioning and Downloading ............................................................................. 45

REFERENCE

5 ZBuilder - the Configuration Tool 49

5.1 Usage.......................................................................................................................... 49

5.2 ZBuilder Overview........................................................................................ .... ..... .... 49

5.3 Templates and Applications ....................................................................................... 52

5.3.1 Selecting a File ...........................................................................................................52

5.4 The Configuration Window........................................................................................ 52

5.5 Documenting the Configuration................................................................................. 53

5.5.1 Printing the Configuration Parameters....................................................................... 53

5.5.2 Associating a Graphic with the Configuration........................................................... 54

5.5.3 Saving the Configuration............................................................................................ 55

6 TAC ZBuilder as a Plug-in 57

6.1 As a Plug-in in TAC Vista.......................................................................................... 57

6.1.1 Starting ZBuilder from TAC Vista............................................................................. 57

6.1.2 Resetting a Neuron ..................................................................................................... 58

6.2 As a Plug-in in LonMaker.......................................................................................... 58

6.2.1 Starting ZBuilder from LonMaker ............................................................................. 58

6.2.2 Configuring a TAC Xenta 120................................................................................... 59

6.2.3 Updating a LonMaker Device Shape ......................................................................... 60

6.2.4 Registering ZBuilder as a Plug-in ............................................... ............................... 61

6.2.5 Resetting a Neuron ..................................................................................................... 62

7 Application Types (Configuration) 63

7.1 Terminal Load and the Heating/Cooling Sequence.................................................... 63

7.2 The 4-pipe Fan-Coil ................................................................................................... 64

7.3 The 2-pipe Fan-Coil ................................................................................................... 64

7.4 The Heat Pump........................................................................................................... 65

7.5 Different Control Signals ........................................................................................... 66

7.6 Peripheral Units and Additional Functions ................................................................ 70

8 Fan Control 71

8.1 General ....................................................................................................................... 71

8.2 Analog Control........................................................................................................... 71

8.3 On/off and Multistage Control ............................................... ..... .... ..... ...................... 72

8.4 Fan Hysteresis ............................................................................................................ 72

8.5 Other Fan Parameters ................................................................................................. 72

8.5.1 Boost........................................................................................................................... 72

8.5.2 Conditioning...............................................................................................................72

8.5.3 Cooling delays........................... ..... .... ...................................................... .................. 73

8.5.4 Heating delays ............................................................................................................ 73

8.5.5 Feedback..................................................................................................................... 73

8.5.6 Interlock...................................................................................................................... 73

8.5.7 Run in deadband................................. ..... .... ...................................................... ..... .... 74

8.6 Fan Control from STR Wall units .............................................................................. 74

9 Connected Devices and Network Parameters 75

9.1 Room Unit .................................................................................................................. 75

9.1.1 STR Modules: I/O Usage ........................................................................................... 76

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TAC Xenta, TAC Xenta 120 Contents

9.1.2 STR Modules: Additional functions .......................................................................... 76

9.2 Occupancy sensor....................................................................................................... 76

9.3 Window Contact......................................................................................................... 77

9.4 Air Quality Equipment............................................................................................... 77

9.4.1 OAD, Outside Air Damper ........................................................................................ 78

9.4.2 CO

Control......................................................................................... .... ..... .............. 78

2

9.4.3 Dehumidification, %RH............................................................................................. 78

9.4.4 Economizer ................................................................................................................ 79

9.5 Free I/O ...................................................................................................................... 80

9.5.1 General....................................................................................................................... 80

9.5.2 Push-button Signals.................................................................................................... 81

9.6 L

ON Properties.......................................................... .... ..... ......................................... 82

9.6.1 Node........................................................................................................................... 82

9.6.2 SNVT ......................................................................................................................... 83

9.6.3 Common SNVT Properties .......................................................................... .... ..... ..... 84

10 Control Issues 85

10.1 Room Temperature Setpoints..................................................................................... 85

10.2 PI parameters........................................................................................... ..... .... .......... 86

10.3 Cascade control.......................................................................................................... 88

10.4 Master-Slave Considerations ..................................................................................... 89

10.5 Actuator Resync and End-points Adjustment............................................................ 90

11 Exception Modes 93

11.1 General....................................................................................................................... 93

11.2 Exception Mode Activation ....................................................................................... 93

11.3 Status when Active..................................................................................................... 95

11.4 Reset Condition.......................................................................................................... 96

11.5 “Other events” explained ........................................................................................... 96

11.5.1 Compressor Lock-out................................................................................................. 96

11.5.2 Fan feedback failure................................................................................................... 96

11.5.3 Flow feedback error ................................................................................................... 97

11.5.4 Loss of space temp input signal ................................................................................. 97

11.5.5 Loss of water temp input signal ................................................................................. 97

11.5.6 Bypass button used as on/off set to off ...................................................................... 97

11.5.7 Exception Mode status............................................................................................... 97

11.6 Some Exception Mode Examples .............................................................................. 98

12 I/O Setup 103

12.1 Hardware Platforms ................................................................... .... ............................ 103

12.2 Digital Input Polarity.................................................................................................. 103

12.3 I/O Ports ..................................................................................................................... 104

12.3.1 Default Usage.............................................................................................................104

12.3.2 Re-arranging the Ports................................................................................................ 104

12.4 Functions Bound to SNVTs....................................................................................... 104

12.5 Temperature Offsets................................................................................................... 105

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Contents TAC Xenta, TAC Xenta 120

APPENDIX

A Setpoint Calculation 109

B SNVT-lists 113

B.1 The Node Object Inputs and Outputs (nvi, nvo) ........................................................ 113

B.2 The Control Object Inputs (nvi)................................................................................. 113

B.3 The Control Object Outputs (nvo).............................................................................. 117

Index 121

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INTRODUCTION

1 About this Manual

TAC Xenta, TAC Xenta 120 1 About this Manual

1 About this Manual

This manual describes a particular process. For information on certain
products, we refer you to the manual or the Help for the product in ques­tion.

For information on how to install software, we refer you to the instruc­tions delivered with the software.

For information on third party products, we refer you to the instructions
delivered with the third party product.

If you discover errors and/or unclear descriptions in this manual, please
contact your TAC representative.

Note

1.1 Structure

We are continuously improving and correcting our documentation.
This manual may have been updated.

Please check our product documentation site at www.tac.com for the
latest version.

The manual is divided into the following parts:

• Introduction

The Introduction section contains information on how this manual
is structured and how it should be used to find information in the
most efficient way.

• Getting Started

The Getting Started section contains a step-by-step description of
how to engineer or carry out different tasks. It also gives you
guided instructions on how to complete a sample project. If you
want more information, see the corresponding chapter in the Ref­erence section of the manual.

• Reference

The Reference section contains more comprehensive information
about various parts of the Getting Started section. It also provides
you with information on alternative solutions not covered by the
Getting Started section.

• Appendix

At the end of the manual we have collected some detailed descrip-

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1 About this Manual TAC Xenta, TAC Xenta 120

!

tions and lists. This information may be useful during special cir­cumstances, but is normally not required.

1.2 Typographic Conventions

Throughout the manual the following specially marked texts may occur.

Warning

Alerts you that failure to take, or avoid, a specific action might result
in physical harm to you or to the hardware.

Caution

Alerts you to possible data loss, breaches of security, or other more
serious problems.

Important

Alerts you to supplementary information that is essential to the com­pletion of a task.

Note

Alerts you to supplementary information.

Tip

Alerts you to supplementary information that is not essential to the
completion of the task at hand.

Advanced

Alerts you that the following information applies to complex tasks or
tasks restricted by access.

1.3 Prerequisites

To be able to profit from the contents in this manual, it is recommended
that you read the following documentation:

• TAC ZBuilder Programming Tool for TAC Xenta 120, Datasheet,
0-003-3010.

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TAC Xenta, TAC Xenta 120 1 About this Manual

• TAC Xenta 121-FC Programmable Fan Coil Application,
Datasheet, 0-003-3057.

• TAC Xenta 121-HP Programmable Heat Pump Application,
Datasheet, 0-003-3058.

• TAC Xenta 121/24 24 VAC Hardware Platform Installation
Instruction, 0FL-4234.

• TAC Xenta 121/230 230 VAC Hardware Platform Installation
Instruction, 0FL-4235.

• TAC Vista IV Engineering Classic Networks, manual, 0-004-7841.

• TAC Vista IV Engineering LNS Network, manual, 0-004-7842.

1.4 Terminology

TAC Xenta Devices

• All programmable T AC Xentas, 280/300/401, will be called Xenta
devices throughout this manual.

• The Xenta 422, 452, and so on will be referred to as I/O modules.

LonWorks Devices

• All other devices will be called LonWorks devices, including the
Xenta 100.

Classic Network

•A Classic Network refers to a TA C Vista system with a Lon-
Works network, TAC Xenta devices and/or LonWorks devices,
using an LTA port connection/communication to the network and
no LNS database. A Classic Network does NOT use any SNVT
bindings.

LNS Network

•An LNS Network refers to a TAC Vista system with a LonWorks
network, TAC Xenta devices and/or LonWorks devices, using an
LTA port with a VNI as the Network Interface (NI) application,
LonMaker 3 and an LNS database. This type of LTA port is
referred to as an LNS port in TAC Vista IV.

TAC Vista Modes

• Engineering Mode. This mode is used when commissioning the
network. In this mode, you can send information to the network
devices as well as service pin each device.

• Operating Mode. This mode provides full communication
between the server and the network device. If the connection
between the server and the device on the network is disrupted, you
will receive an alarm.

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1 About this Manual TAC Xenta, TAC Xenta 120

Some useful terms and abbreviations regarding the zone controller's
application and network communication are explained in the table
below.

Term Description

ASC Application Specific Controller
CCD Climate Control Device
CFR Configuration record, a file included with the

XIF file for devices with many configuration

parameters. Example: TAC Xenta 120 series.
configuration Procedure to design the software for an ASC
DAT Discharge Air Temperature
device plug-in TAC Vista: controller configuration tool

LNS: application to provide custom user inter-

face for devices.
FB Functional Block
Exception Mode Special, configurable behavior of the controller

triggered by certain events.
hardwired an I/O that is physically connected, as opposed

to a SNVT binding
HP Heat Pump
FC Fan Coil
I/O Input/Output
LNS L

ONWORKS Network Servic es; network man-

agement software for L

ONWORKS networks

MS MultiStage
nci configuration parameter; variable that gets its

value from a configuration tool and keeps it

during a power failure
Neuron A microprocessor optimized for control net-

works. Neuron chips have three 8-bit inline

processors: two are dedicated to the communi-

cations protocol and one is a general-purpose

applications processor.
nvi variable that normally gets its value from

another unit on the network through binding

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TAC Xenta, TAC Xenta 120 1 About this Manual

Term Description

nvo variable that is sent to another unit on the net-

work
OAD Outside Air Damper
OAT Outside Air Temperature
PWM (Pulse Width Modulat ion) One type of actuator

control signal
SCC Space Comfort Controller
scpt Standard Configuration Property Type
sequence dia-

gram

A diagram with the Terminal Load on the x-

axis and the (symbolical) controller output sig-

nals on the y-axis. The principal usage of the

TCDs depending on the TL value is shown.
SPID Standard Program ID
SNVT Standard Network Variable Type
STR Room temperature sensor (STR series)
stand-alone The T AC ZBuilder does not run directly ag ainst

a controller or as a plug-in. Generated configu-

rations can only be saved to a file, not down-

loaded to a physical controller or saved to a

database.
TCD Temperature Control Device - Heating and/or

cooling equipment
template A standard configuration file that can be used

as a starting-point for a specific ZBuilder appli-

cation. File name: *.zbt.
TL,

Terminal Load

Terminal Load is a value in the range –100% to

+100%. The value indicates the amount of

power (<0: heating, >0: cooling), needed to

reach the required temperature.
ucpt User Configuration Property Type
XFB-file / XFO-

file

When the XIF-file is imported to L

ONMAKER

Integration Tool it is compiled into two files:

the XFB-file and the XFO-file.
XIF file eXternal InterFace file is a file that, in short,

describes which network variables the device

can handle.

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1 About this Manual TAC Xenta, TAC Xenta 120

Term Description

.zbc File name extension for ZBuilder configuration

files.

.zbt File name extension for ZBuilder template

files. See also template.

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GETTING STARTED

2 Planning the Project

3 Creating the TAC Xenta 120 Con-

figuration

4 Installing TAC Xenta 120 in a

Classic Network

TAC Xenta, TAC Xenta 120 2 Planning the Project

2 Planning the Project

Planning the LonWorks Network in advance saves a lot of time and
effort later in the process. Issues like network structure (groups),
device-naming conventions, and so on should be considered before
actually creating the network.

2.1 Folder Structure

Another consideration is the location(s) on the hard drive where files are
stored. A well-organized project requires a well-organized file struc­ture.

2.1.1 Creating a Project Folder

When starting a new project, you should prepare a directory containing
folders and subfolders as shown below. In this example, we call our
project ACME.

A short description of their intended use and content:

• DeviceDescr – *.mta-files and *.xif-files for the LonWorks net-

work devices.

• Documentation – subfolder with more general information. For

example, useful manuals, data sheets, and technical product infor­mation (TPI). I/O-lists, functional descriptions, and other files cre­ated by DesignBuilder could also be saved here.

• Reports – reports from Vista Server.

• VistaDb – the Vista database.

• VistaGraphics – Vista graphics files.
Once the engineering work is finished, the complete project folder is

transferred from the engineering PC to the site PC. Save the folder
structure as a compressed file (*.zip) to avoid problems with the read­only attributes when storing on a CD.

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2 Planning the Project TAC Xenta, TAC Xenta 120

2.2 Case Study

The following chapters describe how to configure and add a TAC Xenta
120 to a LonWorks network using TAC ZBuilder. Our network exam­ple is based on the case described below.

2.2.1 Description of Facility

We are creating a system for a fictional company that we call ACME
Inc.

The facility is a typical, small two-story office building, served by pack­aged rooftop equipment. The first floor area serves Marketing,
Accounts, Senior Management and the entrance lobby. The second
floor area serves Engineering and Customer Support.

Within the first floor area, the Accounting area is served by a constant
volume rooftop air handling unit. This unit has central station cooling
and central station heating. The space is divided into control zones; the
Accounting area and a conference room with secondary air handling.
The Marketing and Senior Management areas are served by a single
rooftop variable air volume (VAV) air handling unit. The first floor
lobby area is served by a rooftop constant-volume single zone air han­dling unit.

On the second floor, the Customer Support area is served by a single
zone, rooftop constant-volume air handling unit. The Engineering area
is served by a Rooftop VAV air handling unit. A laboratory within the
engineering area is temperature-controlled by a fan-coil unit. The staff
can supervise the system from a PC-based presentation system.

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TAC Xenta, TAC Xenta 120 2 Planning the Project

RTU1

RTU3

RTU2

RTU4

Engineering

Support

Lobby

Accounts

Conference Room

Marketing and Management

Lobby

Conf_Room

2.2.2 Device Description and Naming Convention

Within the first floor area, the rooftop unit serving the Accounting area
is controlled by a Xenta 301, called RTU1.

The secondary air handling unit serving Marketing and Senior Manage­ment is controlled by a Xenta 281, called Conf_Room.

The rooftop unit serving Marketing and Senior Management is con­trolled by a Xenta 401, called RTU2, using four I/O modules.

The air handling unit serving the lobby area is controlled by a Xenta
104, called Lobby.

Within the second floor area, the rooftop unit serving the Customer Sup­port area will be controlled by a Xenta 104, named RTU3.

The rooftop unit serving the Engineering area is controlled by a Xenta
401, called RTU4, using five I/O modules.

The fan-coil unit in the engineering lab area is controlled by a Xenta
121-FC, called Engr_Lab, configured with TAC ZBuilder.

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2 Planning the Project TAC Xenta, TAC Xenta 120

First Floor Second Floor

RTU1

Xenta 301

Conf_Room

Xenta 281

Lobby

Xenta 104

RTU3

Xenta 104

RTU4

Xenta 401

RTU2

Xenta 401

Engr_Lab

Xenta 121-FC

VistaSRV1

Engr_lab

The PC where the presentation system is installed is called VistaSRV1
(in some pictures called VistaSrv_1, but the character “_” should be
avoided) and is located in the Support area.

2.2.3 Devices in the Example

In our example, we use a part of the above network to illustrate how a
Xenta 120 is added.

On the second floor, we have selected the engineering lab fan-coil unit
to illustrate how to configure and install a TAC Xenta 120.

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TAC Xenta, TAC Xenta 120 2 Planning the Project

First Floor Second Floor

Engr_Lab

Xenta 121-FC

RTU4

Xenta 401

VistaSRV1

LTA Card

I/O Modules

(1 & 3)

Conf_Room

Lobby

LonWorks Group 1st_Floor_LW

Xenta Group 1st_Floor

Xenta Group 2nd_Floor

LonWorks Group 2nd_Floor_LW

Engr_Lab

We work with the following device:

2.2.4 Network Structure and Naming Convention in the Example

When adding the Xenta 120 using Vista Workstation, the name of the
network is the name of the company – ACME_Inc. Since the building
has two floors, the network is built with the devices divided into two
Xenta groups called 1st_Floor and 2nd_Floor.

Xenta devices placed on the first floor belong to the Xenta group
1st_Floor and Xenta devices placed on the second floor belong to the
Xenta group 2nd_Floor.

The Xenta 104 is a member of the LonWorks group 1st_Floor_LW and
the Xenta 121-FC is a member of the LonWorks group 2nd_Floor_LW.

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2 Planning the Project TAC Xenta, TAC Xenta 120

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

3 Creating the TAC Xenta 120

Configuration

3.1 ZBuilder Example Overview

ZBuilder is a software tool designed to create a set of configuration
parameters for a specific application, for example a fan-coil with an
electric reheater or a heat pump with a reversing valve.

The parameters are saved in a configuration file which is used by TAC
Vista or LonMaker to install and commission the corresponding TAC
Xenta 120 controller.

For a thorough description of the tool and the working methods, please
refer to Chapter 5, “ZBuilder - the Configuration Tool”, on page 49, and
the other chapters in the Reference section of the manual.

In this chapter you will learn how to use ZBuilder to:

• Start ZBuilder stand-alone

• Select a configuration template

• Adjust the Configuration

• Specify an Exception Mode

• Configure the Inputs/Outputs

• Save and Document the Configuration

3.2 Starting ZBuilder

ZBuilder can be run stand-alone, but can also be started as a plug-in
from TAC Vista or L

To start ZBuilder as a plug-in, the Xenta 120 must be added to a Lon­Works network:

• For more information on how to start ZBuilder as a plug-in from
Vista Workstation, see Section 6.1.1, “Starting ZBuilder from
TAC Vista”, on page 57.

• For more information on how to start ZBuilder as a plug-in from
LonMaker, see Section 6.2.1, “Starting ZBuilder from Lon­Maker”, on page 58.

ONMAKER.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

In the example, we start ZBuilder stand-alone to create the configura­tion file before the Xenta 120 is added to the Lonworks network.

To start ZBuilder as a stand-alone tool

• Click Start, point to All Programs, point to T A C, point to
TAC ZBuilder, and then click TAC ZBuilder.
The TAC ZBuilder Select File window now opens.

3.3 Selecting a Template

To simplify the configuration procedure, you start with a template or
another configuration file similar to the application that you are going
to create.

For more information on how to select files, see Chapter 5.3.1, “Select­ing a File”, on page 52.

In the example, you will start with a template for a 4-pipe fan-coil.

To select a Template

1 In the Select File dialog box, make sure the Select from a list of

Templates option is selected.

2 In the templates list select the required template. In the example,

FanCoil 4-pipe.zbt.

3 Click OK.

3.4 Adjusting the Configuration

Normally you need to adjust the default configuration for the current
application.

In the example, we will adjust the settings to achieve the following:

• The fan will always run for at least 30 seconds when the second
heating stage is turned off.

• When the window is opened, the controller will be turned off.

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

• The secondary heating will start at 80% Terminal Load.

• The second fan stage will start at 70% Terminal Load in cooling.

• The Occupancy state will be signalled via a SNVT; all other
inputs/outputs will be hardwired, that is, physically connected.

3.4.1 Adjusting the Heating/Cooling Parameters

For more information on the control sequence, see Chapter 7.1, “Termi­nal Load and the Heating/Cooling Sequence”, on page 63.

To adjust the Heating/Cooling Parameters

1 Click the Configuration tab.
2 In the tree structure, select Sequences\Cooling.
3 In the Cooling area, in the device type list, select the required

device type. In the example, Increase/decrease

4 Make sure the Hardwired output checkbox is selected.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

Notes

• Increase/decrease actuators need to be resynchronized. This can
be done towards the open or closed position. The specified direc­tion will be used for all active increase/decrease actuators in the
configuration. The default value is Resync actuator towa rd
closed position. For more information, see Section 10.5, “Actua­tor Resync and End-points Adjustment”, on page 90.

• The Cooling icon in the tree to the left has been changed to a
green I/O icon.

You will now have a blue sloping line, showing how the valve will
open with increasing Terminal Load (increasing need of cooling).

5 In the tree structure, select Sequences\Primary heating.
6 In the Primary heating area, in the device type list, select the

required device type. In the example, Increase/decrease.

7 Make sure the Hardwired output checkbox is selected.

Note that you will get a red sloping line, showing how the valve
will close with increasing Terminal Load (decreasing need of heat­ing).

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

8 In the Fully active at box, enter the required value. In the exam-

ple, “80”.

9 In the tree structure, select Sequences\Secondary heating.
10 In the Secondary heating area, in the device type list, select the

required device type. In the example, On/off to include the On/off
reheater.

11 Select the Hardwired output checkbox.
12 In the Activate at box, enter the required value. In the example,

“80”, to determine at what point the reheater will turn on.

13 In the Hysteresis box, enter the required value. In the example,

“15”, to determine the hysteresis before the reheater is turned off.

3.4.2 Adjusting the Fan Parameters

In the example, we use the template’s 2-stage fan, but adjust the on/off
delay times and the deadband.

To adjust the Fan parameters

1 In the tree structure, select Sequences\Fan.
2 In the fan type list, select the required fan type. In the example,

2 stage.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

3 Make sure the Hardwired output checkbox is selected.
4 In the Activation of cooling stages, Second stage box, enter the

required value. In the example, “70”.

5 Select the Show heating/cooling sequence checkbox, to superim-

pose the heating/cooling sequence on the fan sequence.

3.4.3 Adding a Room Unit

Several types of room temperature sensor units can be connected to the
TAC Xenta 120 controller series.

In the example, we want to add the STR 106 to the controller.

To add a Room unit

1 In the tree structure, select Connected devices/Room unit.

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

2 In the Select hardwired room unit area, click the required room

unit. In the example, STR 106 to include that room unit.

3.4.4 Adding an Occupancy Signal

In order to let the controller change between occupancy modes, an occu­pancy signal must be activated.

In the example, we specify an occupancy signal via a SNVT.

To add an Occupancy Signal

1 In the tree structure, select Connected devices\Occupancy.
2 Select the Active checkbox.
3 Make sure the Hardwired occupancy sensor checkbox is cleared ,

which means the SNVT will be used.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

Note that the Occupancy icon in the tree to the left has been
changed to a yellow ‘SNVT’ icon.

3.4.5 Adding a Window Contact

In order to define an Exception Mode, the corresponding hardware
device must be activated.

In the example, we specify a hardwired window contact.

To add a window contact

1 In the tree structure, select Connected devices\Window contact.
2 Select the Active checkbox.

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

3 Select the Hardwired window contact checkbox.

3.4.6 Adjusting the Control Parameters for the Fan

To protect the reheater, it is common to let the fan run some time after
the reheater has been turned off.

In the example, we increase the Off delay time.

To adjust the control parameters for the fan

1 In the tree structure, select Control\Fan.
2 Click the Heating delays text to display the parameters.

Tip

Y ou can also click the + -icon next to the text to display the parameters.

3 In the Off delay heating mode box, enter the required value. In

the example, “30”.

4 Click the Run in deadband text to display the parameters.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

5 Select the Run in deadband when in occupied mode checkbox.

3.5 Specifying an Exception Mode

Exception Modes are used to describe a number of events which in
some way may interfere with normal control.

In the example, we want to turn off all heating/cooling if the window
has been left open for more than two minutes. We describe this case in
an Exception Mode.

To specify an Exception mode

1 Click the Exception Modes tab.
2 Click the Exception Mode 1 text to display the parameters.
3 In the left Activation input list, select the required input. In the

example, Window contact.

4 In the right Activation input list, select the required condition. In

the example, Input is inactive.

5 In the Delays area, in the Delay on box, enter the required value.

In the example, “120”.

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

6 In the Exception mode description area, enter a descriptive text.

In the example, “Window contact”.

Note

The information text can display max. 110 characters.

7 Click the Exception Mode 1 text to hide the parameters.

The information text is now displayed as a label for this exception.

3.6 Changing the Inputs/Outputs configuration

When hardwired inputs and outputs are used in the application,
ZBuilder automatically selects suitable I/O terminals on the controller.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

However, the inputs and outputs can be manually changed to other suit­able ports, if that is required.

ZBuilder also lists SNVTs for functions that you have enabled, but cho­sen not to use hardwired I/O for. These SNVTs need to be bound.

In the example, we choose relay contact K4 for our Secondary heating.

To change the Inputs/Outputs configuration

1 Click the I/O Setup tab.
2 In the IO ports area, in the Output list, click the suggested output

port. In the example, K1, Sec. Heating 1 - 1st stage.

3 Point at K1 and drag the output to the required port. In the exam-

ple to K4.

In the Functions bound to SNVTs list, used SNVTs are displayed as a
reminder that they need to be bound.

In the example, the SNVT nviOccSensor is displayed since the occu­pancy sensor is not hardwired but is signalled via a SNVT.

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TAC Xenta, TAC Xenta 120 3 Creating the TAC Xenta 120 Configuration

3.7 Documenting and Saving the Configuration

The configuration process is now complete. Only documenting and sav­ing the result remains. The saved file is later used for download of the
configuration into the controller.

In the example, this is done in Chapter 4, “Installing TAC Xenta 120 in
a Classic Network”, on page 39.

3.7.1 Documenting the Configuration on a Printout

For archiving purposes, the I/O Setup and some other details of the con­figuration can be easily printed in a standardized form.

To learn more about how to document the configuration, see
Chapter 5.5, “Documenting the Configuration”, on page 53.

In the example, we add some lines of description and make a standard
printout.

To print out the Configuration

1 Click the Overview tab. In the Selected devices area an overview

of the application is shown.

2 In the Description box, enter a descriptive text. In the example,

“4-pipe fan-coil application for the lab in the Engineering area”.

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3 Creating the TAC Xenta 120 Configuration TAC Xenta, TAC Xenta 120

3 Click Print preview.

A Print preview window opens, showing the configuration name,
date and time, the descriptive comment, the I/O connections, and a
list of the used user configuration parameters (UCPTs).

4 Click the Print button in the tool bar to get a printout on the default

printer.

5 Click Close.

3.7.2 Saving the Configuration File

The current configuration may be saved either as an ordinary configu­ration file (*.zbc), or as a configuration template (*.zbt), but in the latter
case only by using the Save as button.

To learn more about how to save the configuration file, see
Chapter 5.5.3, “Saving the Configuration”, on page 55.

In the example, we will save the application as an ordinary configura­tion file.

To save the configuration file

1 Click the Overview tab, click Save.
2 Browse to the folder where the file will be saved. In the example,

C:\ProjectACME\DeviceDescr .

3 Enter the configuration file name. In the example, Engr_Lab.zbc.
4 Click Quit to quit ZBuilder.

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TAC Xenta, TAC Xenta 120 4 Installing TAC Xenta 120 in a Classic Network

4 Installing TAC Xenta 120 in a Classic

Network

The Xenta 120 has to be added to the LonWorks network to be able to
download the parameters from the configuration file to the TAC Xenta
120 using ZBuilder. The Xenta 120 can be added at the same time as the
other devices on the LonWorks network, or it can be added later to an
existing network.

For more information on how to create LonWorks networks, see the
Engineering Classic Networks and/or Engineering LNS Networks.

Before downloading the parameters, you load an already created config­uration into ZBuilder. At this stage you can make changes to the config­uration file and save them to the configuration file if required.

The configuration file is then transferred to the Vista database and from
there downloaded to the Xenta 120.

2a. Load

Config files

(2b. Save as)

ZBuilder

Fig. 4.1: Using ZBuilder as a plug-in for TAC Vista

1. Edit
TAC Xenta 120

3. OK or Apply

Engineering
(and Operating)

TAC Vista

Vista db

Operating
(online)

In the example, we will add one TAC Xenta 120 to an existing Classic
network.

4.1 Adding and Configuring the TAC Xenta 120

You can add and configure Xenta 120 devices in Vista without be ing
connected to the devices.

From the Vista point of view, TAC Xenta 120 is like a LonWorks
device with configuration parameters that can be edited.

TAC Xenta 121

with basic

application sw

4.1.1 Adding a LonWorks Group

The Xenta 120 is added to a LonWorks group in the LonWorks net­work.

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4 Installing TAC Xenta 120 in a Classic Network TAC Xenta, TAC Xenta 120

In the example, we add the LonWorks group, 2nd_Floor_LW to the
LonWorks network, ACME_Inc.

To add a LonWorks group

1 In Vista workstation, change the Vista mode to Engineering.
2 In the Folders pane, right-click the LonWorks network object that

the LonWorks group belongs to. In the example, VistaSRV1­ACME_Inc.

3 Point to New, point to Device, and then click LonWorks Group.

4 Name the LonWorks group. In the example, 2nd_Floor_LW.

4.1.2 Adding a TAC Xenta 120

You need to add the Xenta 120 to a LonWorks gro up on the LonWork s
network.

In the example, we name the Xenta 120 “Engr_Lab” and add it to the
LonWorks group 2nd_Floor_LW on the ACME_Inc Lonworks net­work.

To add a TAC Xenta 120

1 In Vista Workstation, in the Folders pane, right-click the Lon-

Works group the Xenta 120 belongs to. In the example,
VistaSRV1-ACME_Inc-2nd_Floor_LW.

2 Point to New, point to Device, and then click on TAC Xenta 120.

3 Click Next.

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TAC Xenta, TAC Xenta 120 4 Installing TAC Xenta 120 in a Classic Network

4 In the Name box, enter a name for the Xenta 120. In the example,

Engr_Lab.

5 Click Next.
6 In the Neuron ID box, enter the neuron ID of the Xenta 120.
7 In the File system box, browse to the Xenta 120 external interface

file (.xif). In the example,
C:\ProjectACME\DeviceDescr\X120FCw1.xif.

Notes

• The external interface files used together with Xenta 120 are
delivered with V ista. If Vista is installed in the default folder, the
files are found in the C:\Program Files\TAC\TAC Vista [ver­sion]\$ini folder.

• For a Xenta 121-HP (Heat Pump), the external interface file
X120HPw1.xif is used.

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4 Installing TAC Xenta 120 in a Classic Network TAC Xenta, TAC Xenta 120

8 Click Finish.
9 Click Close.

The TAC Xenta 120 device has now been added to the network .

4.1.3 Configuring a TAC Xenta 120

We need to start ZBuilder from TAC Vista and load a configuration file
in order to transfer the parameters from the configuration file to the
Vista database.

In the example, we load the configuration file, Engr_Lab.zbc, created in
the previous chapter.

To configure a TAC Xenta 120

1 In TAC Vista, right-click the new Xenta 120 device. In the exam-

ple, VistaSRV-2nd_Floor_LW-Engr _Lab.

2 Click Edit.

TAC ZBuilder starts.

3 In ZBuilder click Load.
4 In the Select File dialog box, click Browse for Configuration or

Template File.

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TAC Xenta, TAC Xenta 120 4 Installing TAC Xenta 120 in a Classic Network

5 In the Browse for Configuration or Template File, browse to the

configuration file. In the example,
C:\ProjectAcme\DeviceDescr\Engr_Lab.zbc.

6 Click OK.

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4 Installing TAC Xenta 120 in a Classic Network TAC Xenta, TAC Xenta 120

7 Click OK.

Note

The contents of the configuration file have now been loaded into
ZBuilder. Last minute changes may be done in ZBuilder and if so,
you may want to Save as these changes to the existing configura­tion file, or to a new configuration file.

8 Click OK to transfer the configuration parameters to the Vista

database and close ZBuilder.

Tip

You can click Apply to transfer the configuration parameters to the
Vista database without closing ZBuilder.

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TAC Xenta, TAC Xenta 120 4 Installing TAC Xenta 120 in a Classic Network

Note

When editing the configuration file for a Xenta 120 that is already
installed on the LonWorks network and Vista is in Operating mode,
the configuration download to the Xenta 120 will have already
occurred at the ZBuilder Apply/OK command and no download and
commission is needed.

A reset of the neuron of the Xenta 120 is performed by Vista after a
configuration change to make the changes valid. If the reset fails, you
have to perform a manual restart. For more information on how to
reset a neuron, see Section 6.1.2, “Resetting a Neuron”, on page 58.

4.2 Commissioning and Downloading

The configuration parameters have to be downloaded from the Vista
database to the TAC Xenta 120. To be able to do a commission and
download, you have to be connected to the LonWorks network.

To Commission and Download

1 In Vista Workstation, in the folders pane, right-click the Xenta

120. In the example, VistaSRV1-2nd_Floor-Engr_Lab.

2 Click Commission and Download.

3 Click Download parameters from Vista to device.

4 Click OK.

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4 Installing TAC Xenta 120 in a Classic Network TAC Xenta, TAC Xenta 120

5 In the TAC Vista Load – Upload Parameters dialog, click .

6 Click Continue.

7 Click Close.
8 Change the Vista mode to Operating.
9 In the folders pane, refresh the tree structure and check that the

Xenta 120 is online.

Important

A reset of the neuron of the Xenta 120 is performed by Vista after a
configuration change to make the changes valid. If the reset fails, you
have to perform a manual restart. For more information on how to
reset a neuron, see Section 6.1.2, “Resetting a Neuron”, on page 58

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REFERENCE

5 ZBuilder - the Configuration Tool

6 TAC ZBuilder as a Plug-in

7 Application Types (Configuration)

8 Fan Control

9 Connected Devices and Network

Parameters

10 Control Issues

11 Exception Modes

12 I/O Setup

TAC Xenta, TAC Xenta 120 5 ZBuilder - the Configuration Tool

Fan-Coil

or

Heat pump

Room temperature
Offset temp. dial
Bypass button
Occupancy sensor

CO

2

sensor

%RH sensor

Outdoor
temp.
sensor

Duct temp.
sensor

Water temp.
sensor

Outside Air
Damper

Electrical
Heater

Door/
Window
contact
Glass break
sensor

TAC Xenta 120

5 ZBuilder - the Configuration Tool

5.1 Usage

The TAC Xenta 120 series controllers are used for applications that can
be designed and configured in a very flexible way, using ZBuilder.

The tool is a software package that can be run stand-alone or as a device
plug-in to TAC Vista® or L

ONMAKER®.

Fig. 5.1: A TAC Xenta 120 series controller and examples of peripherals

The configuration created by this tool is transferred to LNS or Vista and
is loaded into a TAC Xenta® 120 controller, which has the required set
of Inputs and Outputs and the basic software for the relevant applica-

5.2 ZBuilder Overview

tion.

The purpose of the ZBuilder is to create a software configuration file,
where hardware and/or SNVT input signals are used to affect a specific
Climate Control Device (CCD), resulting in signals directed to hard­ware and/or SNVT outputs.

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The contents of the configuration file are used by TAC Vista or L
M

AKER to download the configuration in a Xenta 120 unit, which

ON-

5 ZBuilder - the Configuration Tool TAC Xenta, TAC Xenta 120

Template
(*.zbt)

Config
parameters

Config file
(*.zbc)

TAC Vista/

LNS

Modified

config file

ZBuilder

TAC Xenta 121

with basic

application sw

already contains the required software for the intended application (for
example Fan-Coil or Heat Pump).

.

Fig. 5.2: Creating and downloading a modified configuration file for a
TAC Xenta 121 application.

ZBuilder has a start page, where the user can start with a template
(*.zbt) or edit a previously saved configuration file (*.zbc).

The configuration is then customized in three tabbed pages:

• Configuration

• Exception Modes

• I/O Setup
The Configuration page lists the available Configuration Modules and

the corresponding parameters.
In the Exception Modes page, up to eight exceptions can be defined, that

is, special action at certain events, for example the desired action when
a window is opened.

The I/O Setup page shows how the inputs and outputs for the selected
Xenta 120 hardware are used. This can also be reconfigured here.

A fourth page, Overview is a graphic presentation of the application,
with a list of the most important parameters and a print function for doc­umentation purposes.

The result is saved as a customized Configuration file.
TAC Vista or LonMaker is used to download the configuration file in

the TAC Xenta 120.
TAC Xenta OP can be used to inspect nvi and nvo values. Due to the

many configuration possibilities, the OP cannot be used to configure the
controller.

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TAC Xenta, TAC Xenta 120 5 ZBuilder - the Configuration Tool

About TAC ZBuilder

The current version of TAC ZBuilder is found in the About TAC
ZBuilder window, which appears if you click on the icon in the upper

left corner.

Fig. 5.3: Finding version information of TAC ZBuilder

Terminal Load

In the Xenta the control program calculates the Terminal Load, a value
in the range –100% to +100%. This value indicates the amount of heat­ing or cooling power required at the moment.

A negative Terminal Load means that heating is required.
A positive Terminal Load means that cooling is required.
The configuration procedure tells the controller how the CCD (Climate

Control Device) should act at different levels of Terminal Load.
This is shown in a sequence diagram, with the Terminal Load on the X-

axis and the output signals to the CCD on the Y-axis.

In ZBuilder a CCD can consist of up to three heating or cooling devices:

• Primary heating

• Secondary heating

• Cooling

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5 ZBuilder - the Configuration Tool TAC Xenta, TAC Xenta 120

Item tree

Units selection:
SI (metric) or
US (inch-pound)

5.3 Templates and Applications

5.3.1 Selecting a File

At start-up, a template (*.zbt) from a list or a configuration file (*.zbc;
or another template) is selected:

The modified result can then be saved as a new template or file.

There are two basic templates: Fan-Coil and Heat pump.
Once an application type (F-C or HP) has been selected, it is not possi-

ble to Load another type.
If you need another type, you will first have to Save the current type or

restart the tool.

5.4 The Configuration Window

In the left part of the Configuration window, there are an item tree and
a drop-down Units selection menu.

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TAC Xenta, TAC Xenta 120 5 ZBuilder - the Configuration Tool

By clicking on a menu in the list, you will be able to inspect and modify
different parameters of the application.

The icons in the tree indicate what kind of parameters are displayed and
some of the properties for the configured devices.

Table 5.1: Icons in Menu tree

Icon Meaning

‘Main’ window, or
Window with additional functions and settings

Window for a configured device that has a hardwired
connection

Window for a configured device that is connected via a
SNVT

Window for a non-used device

5.5 Documenting the Configuration

For documentation and future use, the configuration can be:

• exported as a text file

• printed as a parameter list in a pre-defined format

• associated with a graphical description

• saved as a configuration or a template file

5.5.1 Printing the Configuration Parameters

For documenting and future use, the I/O Setup and other parameter
details of the configuration can be easily printed.

To print the Configuration parameters

1 Click the Overview tab.
2 In the Description field, enter a suitable text.
3 Click Content to select which parts to include with the printout

(or text file export).

4 Click Print preview.

A Print preview window will open, showing the following
(depending on the Content selection):

• Header (application type, configuration file name, and date

and time of preview)

• Description: the text from the Description field.

• Connections: the IO Ports from the I/O Setup.

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5 ZBuilder - the Configuration Tool TAC Xenta, TAC Xenta 120

• SNVTs expected to be bound: the list of SNVTs from the I/O
Setup.

• Exception Mode descriptions: for each defined Exception
Mode the Information text is presented.

• Configuration parameters: a list of the used UCPTs (user con­figuration parameters), their Name, Position (order in table),
Index (bit no., 0 is most significant), and Value.

5.5.2 Associating a Graphic with the Configuration

To give a quick visual cue, a graphic can be shown in the Description
area of the Select File window. Below the picture, the descriptive text
from the Overview Description field also appears.

Fig. 5.4: Graphic and text description of selected Configuration file

Any .jpg-file with the same name and residing in the same folder will
appear in the window.

Example: If the configuration file resides as
C:\Program Files\TAC\TAC ZBuilder\Templates\HeatPump2.zbc
then the graphic
C:\Program Files\TAC\TAC ZBuilder\Templates\HeatPump2.jpg
will appear in the square Description window.
The resolution of the .jpg file should not exceed 120x120 pixels.

Note

In the Overview window there is a graphical view of the Selected
devices. This is a dynamically drawn graphic, updated with any

change in the configuration. This graphic cannot be saved separately
at this stage.

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TAC Xenta, TAC Xenta 120 5 ZBuilder - the Configuration Tool

5.5.3 Saving the Configuration

The current configuration can be saved

• as an ordinary configuration file (*.zbc), or

• as a configuration template (*.zbt),
but in the latter case only by using the Save as button.
Zbuilder is always started with a configuration selected by the user. As

soon as a change has been made, the Save button is made available.
Clicking on Save will immediately overwrite the selected configuration
(unless a template has been used).

In order to preserve the original configuration, use the Save as button,
as this will ask for a file name, folder, and format (.zbc or .zbt). After
this, Save can be used.

Before making the final Save or Save as, you may consider these
points:

•In Overview, enter a descriptive text in the Description field. This

text will appear in the Configuration Parameters printout and the
Select File window described above.

• Associate a descriptive graphic with the same name as the config­uration file, as shown above.

• Decide if the current configuration shall be used as a template or
an ordinary file.

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5 ZBuilder - the Configuration Tool TAC Xenta, TAC Xenta 120

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TAC Xenta, TAC Xenta 120 6 TAC ZBuilder as a Plug-in

6 TAC ZBuilder as a Plug-in

TAC Xenta 120 can be treated as a LONWORKS device with configura­tion parameters that can be edited, using ZBuilder as a plug-in to
TAC Vista or L

6.1 As a Plug-in in TAC Vista

ZBuilder is used as a Plug-in in Vista when Xenta 120 devices are
installed on a classic network.

6.1.1 Starting ZBuilder from TAC Vista

As described in Chapter 4, “Installing TAC Xenta 120 in a Classic Net­work”, on page 39, we start ZBuilder from TAC Vista in order to trans­fer the parameters from the existing configuration file to the Vista
database.

ONMAKER.

To start ZBuilder from TAC Vista

1 In TAC Vista, right-click the new Xenta 120 device and select

Edit.

Fig. 6.1: Starting ZBuilder with an Edit command

TAC ZBuilder should now start.

2 In the ZBuilder Select File window, click Browse for Configura-

tion or Template File and select the configuration file from the

previous chapter, Engr_Lab.zbc.
The contents of the configuration file are now loaded into ZBuilder.

Last minute changes may be done in ZBuilder and, if so, you may
want to Save as these changes to the existing configuration file or
to a new configuration file.

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6 TAC ZBuilder as a Plug-in TAC Xenta, TAC Xenta 120

6.1.2 Resetting a Neuron

A reset of the neuron of the Xenta 120 is performed by Vista after a con­figuration change to make the changes valid. If the reset fails, you must
perform a manual reset.

To reset the neuron

1 In Vista Workstation, in the folders pane, right-click the Xenta 120

device.

2 Point to Advanced Operations and then click Reset Neuron.
3 Click Yes.

6.2 As a Plug-in in LonMaker

ZBuilder is used as a Plug-in in LonMaker when Xenta 120 devices are
installed on an LNS network.

6.2.1 Starting ZBuilder from LonMaker

ZBuilder is started from LONMAKER in order to transfer the parameters
from the existing configuration file to the LNS database.

Important

Do not use the LonMaker Browser to inspect or change the nci, scpt,
or ucpt values. These values can be interpreted in different ways and
only ZBuilder has the logic to interpret the Xenta 120 applications.

To start ZBuilder from LonMaker

1 In LonMaker, in the drawing, right-click the Xenta 120 device.

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TAC Xenta, TAC Xenta 120 6 TAC ZBuilder as a Plug-in

2 Click Configure.

Fig. 6.2: Starting ZBuilder from LonMaker with a Configure command

TAC ZBuilder should now start.

Tips

• Y o u can also click System Plug-Ins on the LonMaker menu and
start TAC ZBuilder from the Plug-Ins window

• If ZBuilder does not start (LonMaker Browser starts instead),
you must register ZBuilder as a plug-in. For more information on
how to register a plug-in, see Section 6.2.4, “Registering
ZBuilder as a Plug-in”, on page 61.

6.2.2 Configuring a TAC Xenta 120

Configuration of the Xenta 120 in ZBuilder transfers the parameters to
the LNS database. If the device is commissioned at the time, the param­eters will also be downloaded to the Xenta 120; otherwise, the parame­ters will be downloaded when the Xenta 120 is commissioned.

For information on how to commission a device, see the Engineering
LNS Networks manual.

To configure a TAC Xenta 120

1 In ZBuilder, in the Select File dialog box, click Browse for Con-

figuration or Template File.

2 Select the required template or browse to the required configura-

tion file.

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6 TAC ZBuilder as a Plug-in TAC Xenta, TAC Xenta 120

The contents of the template/configuration file are now loaded into
ZBuilder. Last minute changes may be done in ZBuilder and, if so,
you may want to Save as these changes to the existing configura-
tion file or to a new configuration file.

3 Edit the configuration parameters as required.
4 Click Save as.
5 Browse to a suitable folder.
6 Click Save.
7 Click OK to transfer the parameters to the LNS database and close

ZBuilder.

If several Xenta 120 devices are to have the same configuration, there
is a great advantage in updating the LonMaker device shape with the
complete configuration. For more information on how to Update a Lon­Maker device shape, see Section 6.2.3, “Updating a LonMaker Device
Shape”, on page 60.

Tip

You can click Apply to transfer the configuration parameters to the
LNS database without closing ZBuilder.

Note

When editing the configuration file for a Xenta 120 that is installed on
the LonWorks network and commissioned, the configuration down­load to the Xenta 120 will occur at the ZBuilder Apply/OK command.

A reset of the neuron of the Xenta 120 is performed by LonMaker after
a configuration change to make the changes valid. If the reset fails, you
must perform a manual restart. For more information on how to reset
a neuron, see Section 6.2.5, “Resetting a Neuron”, on page 62.

6.2.3 Updating a LonMaker Device Shape

If several Xenta 120 controllers are to use the same configuration, you
should use the complete, updated LonMaker Xenta 120 device template
to simplify the download procedure.

To use the LonMaker template for Configuration Download

1 Start ZBuilder from the configured device in LonMaker.
2 Click the Configuration tab.
3 In the tree structure, select LON.
4 Click Update Template.

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TAC Xenta, TAC Xenta 120 6 TAC ZBuilder as a Plug-in

The LonMaker Xenta 120 device template is now updated with the
complete configuration, including the extension records (the spec­ified STR, the Exception Modes texts, and so on).

5 In LonMaker, drag the required number of Xenta 120 shapes to the

drawing. Select Default values as Configuration property source.
The correct parameters will be associated with the new Xenta 120

devices.

6 Commission each Xenta 120 device.
7 Perform a node reset, see Section 6.2.5, “Resetting a Neuron”, on

page 62.

Important

When this configuration method is used, the last step is mandatory to
complete the commissioning procedure.

Note

In order to streamline the work with multiple devices, the Xenta 120
shapes do not contain any Functional Blocks with nvi:s/nvo:s
included. The reason is that the Update Template button does not
update the nci:s connected to that/those FBs that exist in the shape.

To create your own shape containing FBs, make sure the device is con­figured in ZBuilder and that the LNS database is updated (Update
Template), before the shape is created. An SCC FanCoil FB, contain­ing the required variables for binding, can easily be created using the
LonMaker basic Shapes.

6.2.4 Registering ZBuilder as a Plug-in

Normally, TAC ZBuilder is registered together with all other plug-ins
when the network drawing is created. However, it may be necessary to
repeat the registration.

To register ZBuilder as a Plug-in

1 In LonMaker, on the LonMaker menu, click Network Pr operties
2 Click the Plug-in Registry tab.
3 In Already Registered list, select TAC ZBuilder (Version x.x.x).

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6 TAC ZBuilder as a Plug-in TAC Xenta, TAC Xenta 120

4 Click Add.

5 Click OK.
6 Wait until the ZBuilder is registered.

6.2.5 Resetting a Neuron

A reset of the neuron of the Xenta 120 is performed by LonMaker after
a configuration change to make the changes valid. If the reset fails, you
will need to perform a manual reset.

To reset a neuron

1 In LonMaker, in the drawing, right-click the Xenta 120 device.
2 Click Manage.
3 Click Reset.
4 Quit the LonMaker Device Manager dialog box.

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TAC Xenta, TAC Xenta 120 7 Application Types (Configuration)

-100 -83 -50 0

0 33 100

Output
signal

Terminal
Load

Cooling

Fan

Primary
Secondary

heating

7 Application Types (Configuration)

7.1 Terminal Load and the Heating/Cooling Sequence

The function of the TAC Xenta 120 is determined by the Terminal
Load, that is, how much of the heating/cooling power is needed at each
point in time.

It is possible to configure up to two heating devices and one cooling
device. Each of these can be a multistage, pwm, analog, or increase/
decrease device.

The user defines the sequence in relation to the Terminal Load, and the
resulting process is displayed in a diagram with the Terminal Load on
the x-axis and the output signal on the y-axis.

An example of a Heating/Cooling sequence is shown below.

Fig. 7.1: The Heating/Cooling sequence as a function of the Terminal
Load

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7 Application Types (Configuration) TAC Xenta, TAC Xenta 120

Window contact

Heating
coil

1-, 2- or
3-speed Fan

Wall module

Occupancy

sensor

Discharge air

sensor

Incr./decr. or
thermal actuators

Reheating
stage

Economizer Cooling

coil

Humidity

sensor

Outside temp.

sensor

Window contact

Heating/cooling
coil

1-, 2- or
3-speed Fan

Wall module

Occupancy

sensor

Discharge air

sensor

Incr./decr. or
thermal actuator

Water temp.
sensor

Reheating
stage

Economizer

CO2 sensor

Outside temp.

sensor

7.2 The 4-pipe Fan-Coil

An example of a 4-pipe Fan-Coil system:

Fig. 7.2: 4-pipe Fan-Coil

7.3 The 2-pipe Fan-Coil

An example of a 2-pipe Fan-Coil system:

Fig. 7.3: 2-pipe Fan-Coil

Change-over Temperature

In a 2-pipe Fan-Coil unit there is a water temperature sensor for the
incoming flow. When the controller is in Auto mode it will change
between heating and cooling, based on a configurable change-over tem-

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perature level.
There is a heating/cooling change-over hysteresis. With the change-

over temperature at 20 °C (68 °F) and change-over hysteresis of 3 °C
(5.4 °F), the fan-coil, coming from heating, will change to cooling at

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TAC Xenta, TAC Xenta 120 7 Application Types (Configuration)

2726252423222120191817161514

C

o

13

heating start

change-over temp.

cooling start

change-over

hysteresis

(from cooling)

(from heating)

Window contact

Heating/cooling
compressor

1-, 2- or
3-speed Fan

Wall module

Occupancy

sensor

Discharge air

sensor

Isolation
valve

Water temp.
sensor

Reheating
stage

Economizer

CO2 sensor

Outside temp.

sensor

Reversing
valve

21.5 °C (70.7 °F). Coming from cooling it will start heating at 18.5 °C

(65.3 °F).

Fig. 7.4: 2-pipe Fan-Coil changeover temperature parameters

If no water temperature sensor is used, the mode has to be set to HEAT
or COOL by a superior system.

Note

It is possible to allow heating by a secondary heating stage, even if the
mode indicates that the water temperature is too low to allow heating
by the fan-coil itself.

7.4 The Heat Pump

An example of a Heat Pump system.

Fig. 7.5: Heat Pump with isolation and reversing valves

Isolation valve

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In water-sourced heat pumps, the surrounding water flow can be shut
off for energy saving purpose. This is done via an isolation valve con­nected to a digital output.

7 Application Types (Configuration) TAC Xenta, TAC Xenta 120

The isolation valve will open when the application calls for the com­pressor, but the compressor itself is not activated until the configured
delay time has expired.

Reversing valve

A reversing valve is used to set a heat pump in heating or cooling mode.
The valve is controlled by a digital output and there are configurable
restrictions on how the valve is operated in relation to the compressor
operation.

The position is defined by the heating/cooling mode. A delay can be set
defining the time from when the reversing valve is switched until the
compressor may start.

Note

It is possible to allow heating by a secondary heating stage, even if the
mode indicates that the heat pump output is too low to allow heating
by itself.

7.5 Different Control Signals

The following control signals are available:

•On/off

• Multistage: 2 stage, 3 stage

• Increase/decrease

• Pulse Width Modulation (PWM)

•Analog

Note

Normally, the heating and cooling sequences and their control signals
are totally independent of each other. However, because the same
valves and actuators are used, the following two application types use
the same control signals for Primary Heating and Cooling:

• 2-pipe Fan-Coil

• Heat Pump with Reversing valve

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TAC Xenta, TAC Xenta 120 7 Application Types (Configuration)

On/off

Fig. 7.6: An example of an On/off heating sequence

1 Activates device at this Terminal Load, normally 0.
2 Hysteresis value. For the output to go back to off, the Terminal

Load has to decrease to –(20% – 15%) = –5% in this example.

3 Minimum time the output will be on when it is activated.
4 Select which type of device is connected. For a normally closed

device, the output will be off when the device is set to off.
A summary is shown in the table below.

Table 7.1: Output to control different types of devices

Output

Device off Device on

Normally closed off on
Normally open on off

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7 Application Types (Configuration) TAC Xenta, TAC Xenta 120

Multistage

Fig. 7.7: An example of a 3 stage cooling sequence

1 Activates device at this Terminal Load
2 Activates second stage at this load
3 Device fully active at this load
4 Hysteresis value, same for all stages. Note, however, that the

resulting control signal cannot reach into the Dead Band.

5 Minimum time in seconds for ON time in each stage. (The stage

cannot be passed too quickly.)

6 Minimum time in seconds for OFF time in each stage.
7 Lower stages should keep work ing when higher stages are started.

Valid for Multistage applications.

8 Cycle stages (1 => 2 => 3 etc.). If no stage is active, at the next

activation the controller will select the next stage.
The purpose of this function is to achieve a more distributed usage
of the different stages.

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TAC Xenta, TAC Xenta 120 7 Application Types (Configuration)

Incr/decr, PWM (’Duty Cycle’), Analog

Fig. 7.8: An example of an adjusted heating sequence

1 Activates device at this Terminal Load
2 Device fully active at this load
3 Minimum control signal, that is, signal cannot become less.
4 Maximum control signal, that is, signal cannot become greater.

For the Increase/decrease type of control, the actuator stroke time also
has to be specified; from fully closed to fully open.

For the PWM (’Duty Cycle’) type of control, one additional value must
be specified:

•the complete Period (cycle time, the time for one full period)

An output pulse, proportional in length to the control signal, is sent each
period. The ‘duty cycle’ is the ratio between the on-time and the period.

Configurable items:

•Period.

• % of width correlating to 0% control signal (scaling, minimum
duty cycle).

• % of width correlation to 100% control signal (scaling, maximum
duty cycle).

• Delta (if change is less, the value is not repeated for each cycle).

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7 Application Types (Configuration) TAC Xenta, TAC Xenta 120

PWM, US-type

In the US another type of PWM control is sometimes used, applicable
only for actuators giving a position directly proportional to the pulse
width, and not dependant of cyclic updates.

A PWM ‘pulse’ is sent only once, when a change occurs.
In such cases it is beneficial to send an update pulse only when the

width-change is greater than a threshold value, specified in another
parameter:

• Pulse only if change is greater or equal to

7.6 Peripheral Units and Additional Functions

The remaining chapters of the Reference section treat various types of
devices that are normally used with Fan-Coil or Heat Pump applica­tions.

There are also chapters for the Exception Modes and I/O Setup func­tions of the tool.

The devices and parameters are basically presented in chapters with
headings that follow the ZBuilder tabs and windows.

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TAC Xenta, TAC Xenta 120 8 Fan Control

8 Fan Control

8.1 General

The connected fan can be either analog, on/off controlled (1-speed fan
device), or multistage controlled (2 or 3 speeds).

It is also possible to configure in which occupancy modes the fan shall
run. The default setting means the fan will be activated in occupied and
bypass mode, and off in all other occupancy modes, except when there
is a heating or cooling demand.

Important

For devices that can have either hardwired or SNVT input, the SNVT
value, if it is valid, will always take precedence.

This applies even when the Hardwired box is selected!

8.2 Analog Control

With analog control a continuous increase of the fan speed is achieved.

Fig. 8.1: Analog fan control

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8 Fan Control TAC Xenta, TAC Xenta 120

8.3 On/off and Multistage Control

On/off is the same as 1 stage control. In 1 and Multistage control, the
fan speed is increased in steps.

Fig. 8.2: 3 stage fan control

8.4 Fan Hysteresis

The hysteresis value (separate for heating and cooling) applies to all
stages, but can never reach into the Dead Band area.

8.5 Other Fan Parameters

8.5.1 Boost

Boost is used for fans requiring a large torque to start.
The Boost time defines how many seconds the fan will run at maximum

speed, before normal application value is used.

8.5.2 Conditioning

Conditioning means that the fan will always be motioned after a speci­fied interval, if not used before.

The Fan conditioning active time is given in minutes. If the fan always
runs at minimum speed, fan boost will be used.

Inactive time is the maximum interval in hours before the fan is acti­vated, if it has not been used before.

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TAC Xenta, TAC Xenta 120 8 Fan Control

8.5.3 Cooling delays

To prolong the fan effect, there are some different delay times.
The On delay time keeps the fan from blowing before the temperature

control device has reached a suitable temperature.
It is not used if the fan is defined to be running in dead band.
There is also an Off delay time between the fan being forced Off (and

interlocked temperature control device is shut down) and the fan actu­ally is shut off.

If set, the Off delay time also applies to normal control, that is, when the
temperature control device goes below the TL deactivation level.

Not applicable, though, if fan is defined to be running in dead band.

8.5.4 Heating delays

Similarly, there are delay times in heating mode.
The On delay time keeps the fan from blowing before the temperature

control device has reached a suitable temperature.

8.5.5 Feedback

It is not used if the fan is defined to be running in dead band.
There is also an Off delay time between the fan being forced Off (and

interlocked temperature control device is shut down) and the fan actu­ally is shut off. Often this is used to cool a secondary electrical heater.

If set, the Off delay time also applies to normal control, that is, when the
temperature control device goes below the TL deactivation level.

Not applicable, though, if fan is defined to be running in dead band.

If a fan feedback signal, either connected to an I/O port or via a SNVT,
is used, it must be activated here.

A Proof time can be defined, that is, a minimum number of seconds,
after a fan start, until the feedback status should be on. (Otherwise, an
alarm should be considered.)

Important

For devices that can have either hardwired or SNVT input, the SNVT
value, if it is valid, will always take precedence.

This applies even when the Hardwired box is selected!

8.5.6 Interlock

Primary/secondary heating or cooling interlocked to fan.

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8 Fan Control TAC Xenta, TAC Xenta 120

If interlocked to fan, the heating/cooling device is automatically shut
down in case of a fan failure.

The interlocked devices will also be shut down at a fan off signal from
the room unit or by a nviFanSpeedCmd command.

8.5.7 Run in deadband

The fan can be set to run in dead band when in Occupied, Standby ,
or Unoccupied mode.

8.6 Fan Control from STR Wall units

The fan may also be controlled using the fan mode switch on the wall
modules:

• STR106 (with five modes: Auto, Off, Speeds 1, 2, and 3),

• STR107 (with three modes: Auto, Off, On), or

• STR150, 350/351 (free choice of selectable modes can be config­ured).

This function is only available when the zone is in Occupied mode.

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TAC Xenta, TAC Xenta 120 9 Connected Devices and Network Parameters

9 Connected Devices and Network

Parameters

Some additional devices can be connected to improve the system per­formance.

They can be connected to the physical inputs of the controller or be
received as SNVT inputs.

Important

For devices that can have either hardwired or SNVT input, the SNVT
value, if it is valid, will always take precedence.

This applies even when the Hardwired box is selected!

9.1 Room Unit

T A C Xenta 121 can be connected to any of the following temper­ature sensors.

• Room units STR 100/101/102/103/104/106/107/150

• Any 1.8 kohm TAC sensor

• Room unit STR350/351 over a LonWorks network

• Any other Lon sensor
In case several (max 3) space temperature sensors are used, the control-

ler will average their values.
Lon temperature sensors will all be bound to nviSpaceTemp; the system

will separate them internally.
Lon and physically connected devices can be used in parallel or sepa-

rately; their values will be averaged.
For Lon sensors the Offset is set internally in the sensor device. For

other sensors there is a temperature offset input field.
The resulting offset is a numeric addition between the nviSetpntOffset

value and the room unit setting.

Note

For the space temperature and offset values, both hardwired and
SNVT values are used. This is an exception to the general rule about
SNVTs taking precedence over hardwired values.

Some of the sensors require some extra pieces of information.

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9 Connected Devices and Network Parameters TAC Xenta, TAC Xenta 120

9.1.1 STR Modules: I/O Usage

By default, certain ports of the controller will be assigned to certain
STR functions

Hardwired status LED

In STR101/102/103/104/106/107 the status LED can be hardwired to
the controller and is then allocat ed to an out put (an alog Y1 or, as a sec­ond alternative, to a relay output, K).

(In STR150 the status LED is replaced by a ‘Man’ symbol in the LCD
display. Also, in STR150 the uncalibrated temperature values are
shown.)

The LED output can be moved to another port (except for STR150!) in
the I/O Setup window. Note, however, that external power supply will
be necessary (24 VAC or any DC voltage 5–24 V).

9.1.2 STR Modules: Additional functions

Bypass button used as on/off

The Bypass button can be used to toggle between Occupied and Unoc­cupied, or to switch mode to Occupied/Bypass for a specified time.

Activate STR150 reset offset function

There is a so-called hotel reset function for room unit STR150. When
activated, an ‘old’ offset value is not taken into account when going
from Unoccupied to Occupied until the Offset is changed (probably by
a new hotel guest).

Temperature Offset Wheel Scaling

STR102/104/106/107 have plastic pegs on the rear of the offset wheel
to limit the wheel stroke and thus the possible offset values.

In order to allow a full wheel stroke, but still limit the offset values, the
controller can be configured to scale the full stroke according to the set­tings of the two input fields.

9.2 Occupancy sensor

If an occupancy sensor is connected, it can decide the mode of the con­troller. It is possible to define delay times both for switching to occupied
and from occupied. If you walk into a room just to pick something up,
there is no need to switch to occupied (Occupancy sensor on time).

Conversely, if you leave for just a short period of time there is no need
to leave occupied mode (Occupancy sensor off time).

There is also a delay time (Delay before leaving occupancy mode) to
let the Xenta stay in Occupied mode for some minutes after no occu­pancy has been signalled.

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TAC Xenta, TAC Xenta 120 9 Connected Devices and Network Parameters

If no occupancy sensor is connected, the controller assumes that the
room is occupied.

The sensor can be connected either directly to the controller, or via the
network, nviOccSensor. When nviOccSensor has received a valid value,
this is used – whether there is a hardwired sensor or not.

The hardwired sensor value is sent out on the network in nvoOccSensor.
If no sensor is connected, the value OC_NUL is sent out. There is a
definable delay before the operation mode is changed from occupied to
standby in nvoEffectOccup. The change in nvoOccSensor only takes
500 ms in order to make other uses of the occupancy sensor possible
(lighting, alarm, and so on.)

9.3 Window Contact

If a window contact is used to activate an Exception Mode, it has to be
defined as one of the Connected devices.

Select Activate and Hardwired window contact, if applicable.
See also Section 11.6, “Some Exception Mode Examples”, on page 98.

9.4 Air Quality Equipment

The air quality is affected by a number of factors, among them:

•the CO

• the relative humidity, %RH

• outside air via an Economizer
To improve the air quality of the zone, the CO

and fresh outdoor air can be supplied when needed.
An outside air damper can be used to minimize energy consumption by

using outside air to assist in achieving the desired temperature. It can
also be used to maintain the CO

If the temperature of the outside air has a value that enables it to assist
in cooling, the economizer control is activated. A PI controller controls
the outside air damper while the control is in the dead band. When there
is a demand for cooling, the outside air damper is fully opened if the out­side air can assist in controlling the space temp. In heating, the outside
air damper is held at minimum position.

The %RH/CO
If the decision to use the outside air damper is taken elsewhere, this is

signaled to the application via either:

level

2

control may restrict the economizer operation.

2

level can be monitored

2

level in the zone.

2

• Outside air enthalpy level. If the enthalpy is higher than the configured
value, no economizer control is allowed.

• On/off. The state of an nvi determines whether control is allowed.

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9 Connected Devices and Network Parameters TAC Xenta, TAC Xenta 120

• In both cases above, a configuration will specify the position (in per-

cent) the damper should go to if control is not allowed. This since the
normal minimum position can have different usage.

In unoccupied mode, the outside air damper is always fully closed.

9.4.1 OAD, Outside Air Damper

If an Outside Air Damper is used, it can be controlled to minimize the
energy consumption by using outside air to assist in achieving the
desired temperature.

It can also be used to keep the CO
limit.

Only a few parameters are required, among them the OAD minimum
and maximum positions, the TL activation level, and the hysteresis
value.

9.4.2 CO2 Control

The OAD function has limits for its max and min positions. However,
when in CO

control mode, it is possible to allow a position lower than

2

the minimum position. The reason is that if the CO

setpoint (the air quality is sufficient), closing the damper even

CO

2

more may help in saving energy.

9.4.3 Dehumidification, %RH

An indoor %RH senor can be connected. This can work in two config­urable ways.

1 If no external dehumidification equipment is present, the device

can dehumidify the air itself. When the %RH reaches a certain
level, cooling will be forced according to two configurations:

level in the zone within an acceptable

2

value is below the

2

• Start cooling

• Full cooling
The heating control is not forced, which will lead the P/PI control

to maintain the room temperature. If there is an outside air damper,
it will be controlled towards specified minimum position before
cooling is started.

Cooling

%RH

start

Fig. 9.1: Dehumidification by cooling

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TAC Xenta, TAC Xenta 120 9 Connected Devices and Network Parameters

For a heat pump with reversing valve, the compressor will go to
cooling mode. The secondary heating, if present, will be activated
as soon as there is a heating requirement (TL turns negative).

2 The dehumidification is controlled externally. Measured value

together with configured %-level and hysteresis controls a digital
output.

9.4.4 Economizer

The economizer can be controlled in two ways:

• The space temperature is controlled against a cooling setpoint.

• The mixed air temperature is controlled against a specified set­point.

Lockout

Economizer lockout can be used to block usage at unfavorable condi­tions.

Mixed air temperature

If the mixed air temperature is too low, it is an advantage to block the
cool outside air.

Outside humidity

If the outside air humidity is too high, condensation may occur if the air
is cooled.

Outside enthalpy

The outdoor enthalpy level (energy contents of the outdoor air) might
affect economizer cooling capability.

If this level (received as a SNVT) is higher than a specified value, no
economizer control is allowed.

Note

For a Heat Pump that uses air as the heating/cooling source, the OAT
(outside air temperature) value can be used both for the application
and for economizer control.

In this case, the OAT sensor input can be indicated as hardwired or
not, both on the Application page and the Air quality - Economizer
page. However, the selection ‘Hardwired OAT sensor input’ on the
Application page takes precedence over any ‘OAT sensor input’ selec­tion made on the Economizer page.

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9 Connected Devices and Network Parameters TAC Xenta, TAC Xenta 120

9.5 Free I/O

9.5.1 General

Sometimes there is a need to connect digital or analog inputs to SNVT
output signals or vice versa.

Example: hardware input values distributed to SNVTs, but not used for
temperature control (CO

The Free I/O sheet is divided into four groups:

• Hardwired input connected to network output

• Network input connected to hardwired output

• Function input connected to hardwired output

• Hardwired input connected to hardwired output
In all cases, ZBuilder assigns inputs and outputs according to type and

availability. The assigned inputs/outputs are shown in the I/O Setup
page and can be reassigned there.

, %RH).

2

Note

The digital input X2 is treated in a special way. The input is scanned
for status change approximately twice per second. The value after a
status change is kept internally for about 5 seconds. In this way a brief
signal will not be lost to the application.

Hardwired input connected to network output

The following physical inputs can be connected to the following
SNVTs:

• DI (X or digital U) to nvoGenericDI1

• DI (X or digital U) to nvoGenericDI2

• Thermistor input (B or thermistor U) to nvoGenericTemp1

• AI (analog U) to nvoGenericAI
The following connections are available only if they have not already

been used by the application (otherwise they are dimmed):

• AI (B or thermistor U) to nvoWaterTemp

• AI (B or thermistor U) to nvoDischAirTemp

• AI (analog U) to nvoSpaceRH

• AI (analog U) to nvoOutdoorRH

• AI (analog U) to nvoSpaceCO2
For the last three, scale factors are supplied to convert the input voltage

to %RH and ppm respectively.

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TAC Xenta, TAC Xenta 120 9 Connected Devices and Network Parameters

Network input connected to hardwired output

The value in nviDO1 or nviDO2 (0, 0 for open and 1, >0 for close) is set
on a digital output K or V, as assigned in I/O Setup.

Function input connected to hardwired output

Two dedicated functions can be used.
1 Activate Main Switch function (Fan Coil only)

A typical use for this function would be a main switch in a hotel
room, controlled by the room key. The switch can be a digital input
or a SNVT. When the main switch input is active, the occupancy
mode is Occupied. When the input is not active, the occupancy
mode is Standby. A digital output can be made to follow the main
switch status.

2 Activate Aux Pump function (Fan Coil only)

In some cases it may be required to run an auxiliary pump, for
example a circulation pump, as soon as the Terminal Load has a
value not equal to 0, that is, during heating and/or cooling. This is
easily configured here.

Hardwired input connected to hardwired output

Here, two digital outputs can be activated by the status of two digital
inputs (Direct Control1 and Direct Control2); either to follow or to tog­gle at a rising edge of the input.

Example: turn on the light by a light switch.
The input/output assignments will appear in the I/O Setup page.

9.5.2 Push-button Signals

Connecting a Push-button to a Digital Output

1 In the Configuration window, click Free I/O.
2 Expand Hardwired input

nvoGenericDI1.

3 Move to the Exception Modes window and expand a suitable

Exception Mode

4 In the Exception mode is activated when box, select

Generic DI 1 in the drop-down box.

5 In the Status when active box, select one of the Generic DO in

the Sets digital output drop-down box.

and select Connect digital input to

.

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9.6 LON Properties

When the Xenta 121 controller is used in a LonWorks network,
some additional parameters are required.

9.6.1 Node

The node object parameter list describes the configuration parameters
specific to the device as a node object. The node object contains param­eters that define the controller’s general behavior.

Location

A free text field for up to 30 characters to describe, for example, where
the node is located.

Send heartbeat

The minimum send time for the following nvo:s can be specified.
nvoSpaceTemp

nvoUnitStatus
nvoHeatPrimary
nvoHeatSecondary
nvoCoolPrimary
nvoEffectOccup
nvoTerminalLoad
nvoEffectSetpt
nvoFanSpeed
nvoEnergyHoldOff
nvoOccSensor
nvoRawDOStatus

Receive heartbeat

If any of the following nvi:s do not receive an update within a specified
time, this nvi is set to invalid.

nviApplicMode
nviSetPtOffset
nviEnegyHoldOff
nviFanProof
nviOccSensor
nviSpaceRH
nviOutdoorRH
nviSpaceIAQ
nviOutdoorTemp
nviSourceTemp
nviAuxHeatEnable
nviSourceFlow
nviComprEnable

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Space temperature deviation

The smallest deviation from the current setpoint that causes an alarm bit
to be set in nvoSystemStatus. The current setpoint is either the cooling
or the heating setpoint. If normalized setpoint is selected, this is used.

A reset hysteresis value of 0.5 is used.

9.6.2 SNVT

For a number of SNVTs, the difference in value to cause propagation
can be set.

nvoSpaceTemp

A greater difference will send the averaged value of one, two, or three
measured values.

nvoTerminalLoad

A greater difference will propagate the current heat (negative value) or
cool load. If the value has been 100 for more than 15 minutes, the value
101 shall be used (and propagated directly). When value falls below
100, this is disabled.

nvoSetpntOffset

A greater difference will propagate the sum of the local offset and the

nviSetptOffset.
nvoDischAirTemp

A greater difference will propagate the output of the Lon va lue or the
local discharge air temp sensor.

nvoSpaceRH

A greater difference will propagate the output of the Lon va lue or the
local RH space sensor.

nvoOutdoorRH

A greater difference will propagate the output of the Lon va lue or the
local RH outdoor sensor.

nvoSpaceCO2

A greater difference will propagate the output of the Lon va lue or the
local CO

sensor.

2

nvoOADamper

A greater difference of the actual position of the OAD will propagate
the output of the Lon value or the current true position (if SNVT input
says 10% and the configured minimum is 20, then this will be 20).

For all other nvo temperature values the difference value for propaga­tion is 1 °C (1.8 °F). Exception: nvoEffectSetpt uses 0.1 °C (0.2 °F).

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For all other nvo percentage values the difference value for propagation
is 1 %-unit.

9.6.3 Common SNVT Properties

All SNVT inputs are polled at start-up.
The input/output default service type is Acknowledged.

SNVT override

The analog outputs Y1 and Y2 can be overridden using nvoOvrAO1 and
nvrOvrAO2.

The digital outputs K and V can be overriden using the corresponding
bits of nviOvrDO.

For more information about the use of these SNVTs, see the appendix,
Chapter B, “SNVT-lists”, on page 113.

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10 Control Issues

The Xenta 120 controller is based on internal PI software controllers,
separate for heating and cooling.

Additional PI controllers are used for cascade control, humidity, CO
and economizer control.

10.1 Room Temperature Setpoints

For each mode – occupied/bypass, standby, and unoccupied – there are
two setpoints: one for the cooling mode and one for the heating mode.

Room Temperature Setpoint Offset

The temperature setpoint can be adjusted, offset, by means of a wheel
or buttons (STR102/104/106/107 or STR150), over the network
(nviSetPntOffset), or a combination of both.

The range of a setpoint wheel (10 kohm on R1) can be scaled, so that
even if you want to limit the offset to +/-1 °C (+/-1.8 °F), it is possible
to use the full potentiometer angle of a STR102/104/106/107 sensor.

This will have the same effect as applying the physical limitation pins
in the STR, but will give the customer the perception of a wider control
span.

For adjustment over the network, both method A and method B of the
L

ONMARK profile are supported, as this is defined in the Space Comfort

Controller functional profile. See the appendix, Chapter A, “Setpoint
Calculation”, on page 109.

,

2

Modifying the setpoint offset effects the occupied and stand-by mode
setpoints, but not the unoccupied. The adjustment will effect both the
heating and cooling setpoints simultaneously.

Important

If the integral time I for PI control is set to 0, the default setpoints
should not be used. For an explanation, see the next section.

Ignore offset in Standby mode

If selected, the offset will only affect the setting in Occupied mode.

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Expose normalized effective setpoint

The averaged/normalized value of the current heating and cooling set­points can be displayed, instead of one of the two separate (heating/
cooling) setpoints. The normalized value is sent out on nvoEffectSetpt.

10.2 PI parameters

The characteristics of the Terminal Load are different in different
regions. This is also true for how the control sequences should behave
for different temperature control devices.

For example, with a modulating output it is better to use PI control,
while with multistage (on/off) it is sometimes preferable to have propor­tional control.

To allow the user to choose, the PI parameters can be specified individ­ually for:

• cascade control (see below)

•CO

2

• cooling

• economizer

• heating

Considerations when I=0

Setting the integral time to 0 results in pure P control.

Note

Setting the integral time to 0 for heating/cooling, will affect the width
of the deadband, see the examples below.

First, consider the situation when I>0.
The setpoints for heating and cooling determine the width of the dead-

band. The gain determines the slope of the control ramp.

Terminal
Load

100%

Heating

Cooling

0%

SP

H

C

ΔT

19 21 23 25

100

=

G

= 50

H

ΔT

GC=

ΔT

100

ΔT

= 50

°C

SP

Fig. 10.1: I>0, Setpoints and Gain for Heating and Cooling

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19 21 23 25

100%

0%

ΔT

ΔT

G

H

=

100

ΔT

= 50

GC=

100

ΔT

= 50

50%

Terminal
Load

Cooling

SP

H

Heating

SP

C

°C

Here we have a sufficient deadband between heating and cooling.
When I=0, the controller “Gain ramps” are placed so that the SP values

will be situated at the 50% TL value, which is in the middle of the

ΔT

interval.
So, to get the same TL behavior when I=0, the two setpoints have to be

separated, each with

Fig. 10.2: I=0, Setpoints separated, Gain as before

ΔT/2, as shown in Fig. 10.2.

If we had failed to do so, we would have got the station in Fig. 10.3.

Terminal
Load

C

ΔT

100

ΔT

Cooling

°C

= 50

100%

50%

0%

Heating

SP

SP

H

ΔT

20 21 22 23 24

100

G

=

= 50

H

ΔT

GC=

Fig. 10.3: I=0, Setpoints and Gain unchanged, as in the first case

The deadband has decreased to half of its first value. The dashed line
shows the behavior with decreasing need of cooling.

The corresponding behavior will occur with decreasing need of heating.

Important

Setpoints that are too close, combined with an insufficient slope (gain)
may lead to the disappearance of the deadband, and an undesired
behavior of the heating/cooling device, see Fig. 10.4.

This implies that when I=0, the default setpoint values probably
should be adjusted, to new, more separated values.

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100%

0%

ΔT

ΔT

G

H

=

100

ΔT

= 25

GC=

100

ΔT

= 25

50%

19 20 21 22 23 24 25

Terminal
Load

Cooling

SP

H

Heating

SP

C

°C

Setpoint

Zone temperature

Discharge air
temperature

Controller zone
temperature

Device

Controller
heating/cooling

nvoSupplySetpt

nvoDischAirTemp

Fig. 10.4: I=0, Same Setpoints, but lower Gain: no deadband at all!

10.3 Cascade control

It is possible to configure the temperature control to use cascade control,
that is, controlling the space temperature in cascade with the discharge
air temperature.

The discharge air temperature sensor has two purposes:

• To restrict the discharge air temperature to be within a certain range.
Even if there is a substantial need for cooling in the room, it would be
uncomfortable for the people in the room if the discharge air tempera­ture were too low.

• To achieve better temperature control by means of cascade PI control.
When cascade control is enabled, the controller uses an additional PI

controller to calculate the discharge air temperature setpoint (nvoSuppl-
ySetpt) based on the current zone temperature.

Fig. 10.5: Cascade control with valid discharge air temperature

The controller sends the discharge air temperature in the variable
nvoDischAirTemp. If the controller does not have a sensor, the invalid
value is sent. The variable is sent on the network when the temperature
value has changed more than a specified amount since the last sendout.

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Setpoint

Zone temperature

Discharge air
temperature

Device

Controller
heating/cooling

If no valid discharge air temperature is available, normal heating/cool­ing control will rule, until a valid temperature value returns.

Fig. 10.6: Normal control when discharge air temperature is invalid

10.4 Master-Slave Considerations

If one or several identical temperature control devices are to be con­trolled in parallel with a master, some special considerations must be
observed.

1 The slave configuration must be of the same type as the master; in

principle, the same configuration file should be used.

2 There is one important exception from 1), though: You are not

allowed to define Exception Modes for the slave!
Reason: Exception Modes have higher priority than nviUnitOver-
ride (see the next point).

3 All relevant control signals are sent from the master to the slave

when nvoUnitStatus (master) is bound to nviUnitOverride (slave).

4 Resync on the master (see the following section) will not affect the

slave; each controller has to get its own Resync command.

When a chain of controllers are installed, it is possible to give feedback
to the master through nvoEnergyHoldOff. In the example below, the sig­nal nvoEnergyHoldOff is set by the SNVT nviEnergyHoldOff, or if the
window contact is opened.

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The number of slaves are not limited, the illustration below is only an
example.

Slave 2

nv59 nviUnitOverride

nv14 nviEnergyHoldOff

Window

contact

NC

nv49

nviUnitOverride

nv59

nv14 nviEnergyHoldOff

Window

contact

NC

nv59

nv14 nviEnergyHoldOff

nvoEnergyHoldOff

Slave 1

nv49

nviUnitOverride

nvoEnergyHoldOff

Master

Window

contact

NC

nv27

nvoUnitStatus

Fig. 10.7: An example of a master with two slave controllers.

10.5 Actuator Resync and End-points Adjustment

Resync

All outputs configured as inc/dec actuators need to be resynchronized to
establish their true position. The resync occurs on three occasions:

1 At restart of the controller
2 Thereafter, at a cyclic interval of 18 hours
3 Initiated via the network (nviDOResync)

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Resync can be made towards the open or the closed position, see
Section 3.4.1, “Adjusting the Heating/Cooling Parameters”, on
page 27.

1) is performed at a randomly chosen point during the first 42 minutes

after the restart.

2) is repeated every 18 hours, using the resync in 1) as start-point.

3) is separated from the 18-hour cycle and is done by a request via the

nviDOResync variable. Its value must be >0 and state=1. When the
resync has been performed, state is set to state=FF.

Important

At a master-slave configuration, nviDOResync on the master will not
affect the slave controller. A separate nviDOResync has to be issued
for the slave.

Resync is not visible in the application, which retains its normal values.
Resync cannot be aborted.

End-point Adjustment

In addition to the resync process, an adjustment to the actuator position
is performed each time the actuator is controlled to an end-point posi­tion; open or closed.

If the position is set to be 0 (fully closed) or 100 (fully open), from an
arbitrary point in between, an extra 10% is added to the calculated run­time. In this way, the well-defined end position should be safely
reached. After that, if the signal remains at its end position, no signal is
active.

Important

If the min and max control signals are set to values away from the end­points, this type of end-point adjustment will not be performed.

In such a case, the application has to rely on the 18-hour resync or the
forced nviDOResync signal.

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TAC Xenta, TAC Xenta 120 11 Exception Modes

11 Exception Modes

11.1 General

Exception Modes are used to handle situations that arise at certain
events. Typical examples are: signals from a window contact, freeze
protection, and morning warm-up.

The eight Exception Modes can be defined in any order and there may
be unused Modes in between.

Note

Events that relate to inputs which can be hardwired need to first be
defined in the corresponding dialog window under the Conf iguration
tab (even if they use SNVT input instead).

11.2 Exception Mode Activation

An exception is a specified event which may interrupt normal control
and lead to some other action.

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The following events can be used:

Level, high or low, has been exceeded

• Space Temp above / below

• Water Temp above / below

• Discharge air Temp above / below

• Mixed/Supply air Temp above / below

• Outside Air Temp above / below

• Generic Temp 1 (no application) above / below

• Setpoint offset above / below

• CO2 sensor above / below

• Humidity sensor above / below

• GenericAI (0-100%) above / below

• TerminalLoad (0-100%) above / below, for example ABS (Termi­nalLoad), the numerical value only, since the TerminalLoad can
be -100% to +100%)

Note

A dimmed item in the list indicates that this event cannot be used. The
reason is that the event has not been defined in any dialog window
under the Configuration tab.

Contact opened or closed

• Window contact connected to ground / contact is open

• Occupancy sensor connected to ground / contact is open

• Generic DI1 or DI2 connected to ground / contact is open

SNVT input value

• NviEmergOverride = EMERG_PRESSURIZE*

• NviEmergOverride = EMERG_DEPRESSURIZE*

• NviEmergOverride = EMERG_PURGE

• NviEmergOverride = EMERG_SHUTDOWN

• NviApplicMode = HVAC_MRNG_WRMUP /
HVAC_NIGHT_PURGE / HVAC_PRE_COOL / HVAC_OFF /
HVAC_TEST / HVAC_EMERG_HEAT / HVAC_FAN_ONLY

All these modes can be used to activate an exception mode. By
treating these specific operations as exceptions, the user is free to
define the appropriate action.

• NviDO1 or NviDO2 (state = 1)

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Two digital input values, received as SNVTs (configured as free
I/O).

Other events

• Compressor lockout

• Fan feedback failure

• Flow feedback error

• Loss of space temp input signal

• Loss of water temp input signal

• Bypass button used as on/off set to off
For a discussion about these events, see below.

Activation allowed when

In addition to the event itself, some other conditions may be met to
allow the activation of the Exception mode; for example, if the control­ler is in cooling or heating mode, or if nviApplicMode is in
HVAC_COOL or HVAC_HEAT.

Note

The nviApplicMode settings overrule the Controller mode settings.

Delays

Delay times can be defined, both for activation and reset of the Excep­tion mode.

11.3 Status when Active

The action list when the conditions for an Exception mode is fulfilled
includes the following:

• Restart requirement (see Chapter 11.4, “Reset Condition”, on
page 96)

• Cooling control

• Application mode override

• Primary and Secondary heating control

• Fan control

•OAD control

• Auxiliary pump (Fan-coil) / Isolation valve (Heat Pump) control

• Set generic digital output 1–4 (example: see Chapter 9.5.2, “Push­button Signals”, on page 81)

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Exception mode control

It is possible to specify normal control for one or more of the devices,
but it is also possible to configure a specific override condition.

Note

When a percentage value is entered, this value relates to the full, un­scaled output signal.

11.4 Reset Condition

Normally, an Exception mode is reset when the defined reset condition
is obtained. However, it is possible to specify that the device needs a
restart (power cycle) to recover from the exception mode.

11.5 “Other events” explained

11.5.1 Compressor Lock-out

Compressor lock-out is an error state in a Heat Pump and is defined by
unacceptable temperature in the incoming medium (water or air) or
insufficient water flow.

Compressor lock-out can also be received as a digital input from the
device itself. This case is selected directly in the Application window
for the Heat Pump.

11.5.2 Fan feedback failure

The heating and cooling devices can be interlocked with the fan, which
means that the temperature control device cannot start unless the fan is
running. If the fan is forced to Off, or the feedback signal fails, this
could be treated as an exception.

If a fan status input signal is available, this is used for the interlock (if
configured). The status input could be a feedback signal from the fan or
an air flow switch. If no fan feedback is available, the system will work
as a supervisor so that there cannot be any situations where the temper­ature control device is running without a fan.

There is a configurable timer defining the allowed latency from fan start
to feedback. If a fan On delay timer is defined, the totally allowed
latency will be the sum of these times. Failing fan feedback within this
defined start up time, or in run-time, will cause an alarm condition and
turn all interlocked devices off. It will also turn off the fan signal.

The controller will then try to restart the fan every 30
out activating the temperature control device. If a feedback is received
within the configured latency, the fan will shut down, clear the alarm,

th

minute, but with-

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TAC Xenta, TAC Xenta 120 11 Exception Modes

and leave the error state. Normal control will resume.The SNVT nvo­SystemStatus.bit15 is set if condition “Fan interlock activated” is true.

11.5.3 Flow feedback error

For a heat pump, nvoSystemStatus bit 12 is set if an expected flow is
missing. For example, when the isolation valve is open there should be
a flow feedback, but when it is closed or opening , no signal is expected.

If a flow feedback error is active, then both heating and cooling valves
will shut down immideately, and when the flow feedback error is no
longer active, the valve(s) will assume operation.

11.5.4 Loss of space temp input signal

Obviously, loss of space temperature is a serious error for the tempera­ture control.

An exception mode might set the control to some estimated medium
value.

11.5.5 Loss of water temp input signal

Loss of water temperature may or may not be a serious error for the tem­perature control, depending on other circumstances, which have to be
considered.

For example, if it is known that the cooling water temperature rarely
rises to unacceptable levels, a simple indication may be sufficient.

11.5.6 Bypass button used as on/off set to off

The button on the STR100 series or Lon devices can be configured
either as a Bypass button or an On/off button.

Pressing the Bypass button will take the controller to Occupied mode
for a configurable period of time. On time-out it will return to the mode
indicated in nviManOccCmd.

If configured for On/off, this will toggle the controller between Occu­pied and Unoccupied. This may be overridden by a superior system.

11.5.7 Exception Mode status

When an Exception Mode is activated, it sets its corresponding bit in
nvoSystemStatus. Bit 0 is set as soon as one or more Exception Modes
are active.

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11.6 Some Exception Mode Examples

Below we describe the settings for four common situations that are han­dled as Exception Modes.

Exception Mode 1 - Freeze Protection

In this example, cooling will be turned off (if it was active) and the pri­mary heating will be set to 50% when the space temperature reaches
below 10 °C (50 °F), in order to prevent freezing in the space.

The fan will also be set to 50% speed. When the temperature reaches
above 13 °C (55 °F), normal control will be resumed.

To avoid the exception mode being activated due to temporary draft, the
temperature must be below 10 °C (50 °F) for 20 s to activate the freez­ing protection and the temperature must be above 13 °C (55 °F) for 30 s
to resume normal control.

The exception is enabled when the controller is cooling and heating.

Fig. 11.1: Exception Mode 1 - Freeze Protection

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Exception Mode 2 - Pressurize

This exception is controlled by the value of nviEmergOverride. When
it has the value EMMERG_PRESSURIZE, heating and cooling will be
turned off, the outside air damper will be fully opened, and the fan will
run at full speed.

This exception can be triggered in any mode.

Fig. 11.2: Exception Mode 2- Pressurize

Exception Mode 3 - Depressurize

This exception is controlled by the value of nviEmergOverride. When
it has value EMMERG_DEPRESSURIZE, heating and cooling will be
turned off, the outside air damper will be closed, and the fan will be
stopped.

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This exception can be triggered in any mode.

Fig. 11.3: Exception Mode 3- Depressurize

Exception Mode 4 – Window Contact

This exception is controlled by the windows contact. The window con­tact has been enabled in the Configuration tab, under “Connected
devices”.

When the window is detected as open for 120 s, heating, cooling, and
the fan will be turned off. When the window has been closed for 10 s,
normal climate control is resumed.

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