Rockwell Automation Allen-Bradley 1794-IJ2XT, Allen-Bradley 1794-IJ2K, Allen-Bradley 1794-IJ2 User Manual

FLEX I/O Frequency Input Module

Catalog Numbers 1794-IJ2, 1794-IJ2K, 1794-IJ2XT User Manual

Important User Information

WARNING

IMPORTANT

ATTENTION

SHOCK HAZARD

BURN HAZARD

Solid state equipment has operational characteristics differing from those of electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (publication SGI-1.1

http://literature.rockwellautomation.com

) describes some important differences between solid state equipment and hard-wired electromechanical devices. Because of this difference, and also because of the wide variety of uses for solid state equipment, all persons responsible for applying this equipment must satisfy themselves that each intended application of this equipment is acceptable.

In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use or application of this equipment.

The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for actual use based on the examples and diagrams.

No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software described in this manual.

Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell Automation, Inc., is prohibited.

Throughout this manual, when necessary, we use notes to make you aware of safety considerations.

available from your local Rockwell Automation sales office or online at

Identifies information about practices or circumstances that can cause an explosion in a hazardous environment, which may lead to personal injury or death, property damage, or economic loss.

Identifies information that is critical for successful application and understanding of the product.

Identifies information about practices or circumstances that can lead to: personal injury or death, property damage, or economic loss. Attentions help you identify a hazard, avoid a hazard, and recognize the consequence.

Labels may be on or inside the equipment, such as a drive or motor, to alert people that dangerous voltage may be present.

Labels may be on or inside the equipment, such as a drive or motor, to alert people that surfaces may reach dangerous temperatures.

Allen-Bradley, Rockwell Automation, FLEX I/O, RSLinx, RSLogix 5000 and TechConnect are trademarks of Rockwell Automation, Inc.

Trademarks not belonging to Rockwell Automation are property of their respective companies.

Summary of Changes

This manual contains new and updated information. Changes throughout this revision are marked by change bars, as shown to the right of this paragraph.

New and Updated Information

This table contains the changes made to this revision.

Topic Page

Inclusion of two catalogs, 1794-IJ2K and 1794-IJ2XT 1 The first chapter has been updated with the following topics:

•The FLEX System

•Type of Modules

•The FLEX I/O Module in a Logix Control System

The wiring illustration for terminal base units has been updated. 20 The following topics have been added:

•Configure Your FLEX I/O Module with RSLogix 5000

(Chapter 3)

•Troubleshoot the Module (Chapter 5)

•Electronic Data Sheet (EDS) Files

The Specifications topic (Appendix A) has been updated to include specifications for 1794-IJ2K, and 1794-IJ2XT.

"Program Your Module" is now moved to the appendices section. It was previously Chapter 3 in the last revision.

35 59 55

iii Publication 1794-6.5.11 - September 2011

iv Summary of Changes

Notes:

Publication 1794-6.5.11 - September 2011

Overview of the Frequency Input Module

Summary of Changes

New and Updated Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Preface

Who Should Use This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Purpose of the Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

About the Vocabulary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Related Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Common Techniques Used in this Manual. . . . . . . . . . . . . . . . . . . . . . xii

Chapter 1

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

The FLEX System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Type of Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Usage of the Frequency Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . 2

The FLEX I/O Module in a Logix Control System . . . . . . . . . . . . . . . 3

Typical Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Input Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Selecting the Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Output Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Implementing Application Features . . . . . . . . . . . . . . . . . . . . . . . . . 7

How Frequency Is Calculated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Frequency Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Termination on Number of Pulses . . . . . . . . . . . . . . . . . . . . . . . . . 10

Missing Pulse Multiplier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Direction Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Chapter Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Chapter 2 Install Your FLEX I/O Frequency Input Module

v Publication 1794-6.5.11 - September 2011

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Before You Install Your Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Install the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Mount on a DIN Rail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Mount on a Panel or Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Mount the Frequency Input Module on the Terminal Base

Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Wiring Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Wiring the Terminal Base Units (1794-TB3G shown) . . . . . . . . . 20

Wire the Terminal Base Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Connect Wiring to the FLEX I/O Frequency Input Module. . . . 21

Connecting Wiring Using a 1794-TB3G, 1794-TB3GK or

1794-TB3GS Terminal Base Unit. . . . . . . . . . . . . . . . . . . . . . . . . . 22

Resolution and Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Examples of Wiring to a 1794-TB3G Terminal Base Unit . . . . . . 27

Chapter Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

vi Table of Contents

Configure Your FLEX I/O Module with RSLogix 5000 Software

Troubleshoot the Module

Read and Write Configuration Maps for the FLEX I/O Module

Chapter 3

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Add and Configure the FLEX I/O Module. . . . . . . . . . . . . . . . . . . . . 29

Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Chapter 4

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Status Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Diagnostic Bits in Word 5 of the BTR File . . . . . . . . . . . . . . . . . 37

Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Chapter 5

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Configure Your Frequency Input Module . . . . . . . . . . . . . . . . . . . . . . 39

Read Data From Your Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Map Data for the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Frequency Input Module Image Table Mapping . . . . . . . . . . . . . 40

Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Specifications

Electronic Data Sheet (EDS) Files

Schematics

Programming Your Module with PLC Processors

Appendix A

What This Appendix Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Appendix B

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Updating EDS File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

EDS Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Appendix C

What This Appendix Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Gate Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Output Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

DC to DC Converters – 24V DC Power Supplies . . . . . . . . . . . . 63

Appendix D

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Enter Block Transfer Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

PLC-2 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

PLC-3 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

PLC-5 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

PLC-5/250 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Publication 1794-6.5.11 - September 2011

Index

Preface

Read this preface to familiarize yourself with the rest of the manual. It provides

information concerning:

• who should use this manual

• the purpose of this manual

• related documentation

• conventions used in this manual

• terminology used in this manual

Who Should Use This Manual

Purpose of the Manual

We assume that you have previously used an Allen-Bradley programmable

controller, that you are familiar with its features, and that you are familiar with

the terminology we use. If not, read the user manual for your processor before

reading this manual.

This manual is a reference guide for the 1794 Frequency Input Modules. It

describes the procedures for installing, configuring and troubleshooting your

module.

For information on See

Overview of the Frequency Input Module Chapter 1 Install Your FLEX I/O Frequency Input Module Chapter 2 Configure Your FLEX I/O Module with RSLogix 5000 Software Chapter 3 Read and Write Configuration Maps for the FLEX I/O Module Chapter 4 Troubleshoot the Module Chapter 4 Specifications Appendix A Electronic Data Sheet (EDS) Files Appendix B Schematics Appendix C Program Your Module with PLC Processors Appendix D

About the Vocabulary

ix Publication 1794-6.5.11 - September 2011

In this manual, we refer to:

• the frequency input module as the “input module”

• the Programmable Controller as the “controller”

x Preface

Common Techniques Used in this Manual

x xxxxxxxxxxxxx

The following conventions are used throughout this manual:

• Bulleted lists such as this one provide information, not procedural steps.

• Numbered lists provide sequential steps or hierarchical information.

• Italic type is used for emphasis.

Information on how to install the FLEX I/O DC Power Supply (Catalog No. 1794-PS13, 1794-PS3).

In-depth information on grounding and wiring Allen-Bradley programmable controllers.

A glossary of industrial automation terms and abbreviations.

Publication 1794-6.5.11 - September 2011

Chapter

I/O moduleTerminal base

1794-IRT8

Adapter

45568

Overview of the Frequency Input Module

Overview

The FLEX System

This chapter provides a description of the application and capabilities of the

1794 FLEX I/O Frequency Input module. It also explains the general

algorithm for calculating frequency.

Topic Page

The FLEX System 1 Type of Modules 2 Usage of the Frequency Input Module 2 The FLEX I/O Module in a Logix Control System 3 Typical Applications 5 Input Capabilities 6 Output Capabilities 7 How Frequency Is Calculated 8 Chapter Summary 12

FLEX I/O is a small, modular I/O system for distributed applications that

performs all of the functions of rack-based I/O. The FLEX system contains

the following components shown below:

• Adapter – transfers read and write configuration data to and from the I/O module

• terminal base – contains a terminal strip to terminate wiring for two- or three-wire devices

1 Publication 1794-6.5.11 - September 2011

2 Overview of the Frequency Input Module

• I/O module – contains the bus interface and circuitry needed to

perform specific functions related to your application

The 1794 FLEX system consists of an adapter module, terminal base unit, DIN rail, power supply, and adapter cabling components. You can use up to 8 terminal bases per adapter module.

For detailed instructions to set up and install your module, refer to the topic, Install Your FLEX I/O Frequency Input Module, on page 13.

Type of Modules

The FLEX I/O Frequency Input modules refer to the following catalogs.

Catalog No. Voltage Inputs Outputs Description

1794-IJ2 24V DC 2 2 Digital – 2-pt 24V DC input frequency

module

1794-IJ2K 24V DC 2 2 Digital – 2-pt 24V DC input frequency

module, conformally coated.

1794-IJ2XT 24V DC 2 2 Digital – 2-pt 24V DC input frequency

module for extended temperature.

The frequency input module is an intelligent I/O module designed to perform high-speed frequency algorithms. The module provides:

• 2 Frequency Inputs,

• 2 Gate Inputs and

•2 Outputs.

The Frequency Inputs can accept frequencies up to 32,767 Hz and it accepts and returns binary data.

Usage of the Frequency Input Module

Publication 1794-6.5.11 - September 2011

The FLEX I/O Frequency Input module is essentially a tachometer with the capability of reporting frequency, acceleration, and direction. Outputs are activated by alarms. Input devices range from magnetic pickup to flowmeters, to incremental encoders to proximity detectors. This intelligent I/O module is designed to perform high-speed frequency algorithms.

Power to the module is supplied from an external power supply. All power for input devices (24V DC) is supplied by the I/O module. Outputs are used to set alarms depending on the input conditions.

The module measures frequency over a user-specified time interval. A frequency calculation can start before the time interval has elapsed, if a user-specified number of frequency input pulses have occurred.

Overview of the Frequency Input Module 3

500/50 mV

50 mV

Select

24V IEC 1+

Magnetic

500/50 mV

Magnetic

Gate input

Frequency input

CRISP

Bus interface

Output 0

Output 1

Inter-processor

communication,

uP system 0/1

From uP system 1

Data To/From FlexBus

Invert

Y/N

Invert

Y/N

Processing

Counter

Frequency / count data

uP system 0

Output control

Input control

Direction data

IEC 1+/Contact

Input

VORTEX

Vortex

3Vin 6Vin 24V power

IEC 1+/Contact

Input

50 mV Select

GND

Inputs

Module

FlexBus

24V Power

24Vpower

45388

The primary use of the module is accurate, high-speed frequency measurement. A high-speed internal clock is synchronized with the frequency input to count over a user-selected sampling time or a user-defined number of frequency input pulses.

All power for input devices (4 devices, 24 V DC @ 15 mA max) is supplied by the I/O module.

The FLEX I/O Module in a Logix Control System

The frequency input module performs high-speed frequency and/or scaling calculation operations for various industrial applications. The module interfaces with a FLEX I/O family adapter which then communicates with a programmable controller processor that has block-transfer capability and external I/O devices.

The adapter transfers data to the module (block transfer write) and from the module (block transfer read) using BTW and BTR instructions in your ladder diagram program. These instructions let the adapter read input values and status from the module, and let you write output values and configure the module mode of operation. The following illustration describes the communication process.

Publication 1794-6.5.11 - September 2011

4 Overview of the Frequency Input Module

FREQ

GATE

FREQUENCY INPUT 2 CHANNEL

1794-IJ2

F0F

FREQ

GATE

OUT

45339

The adapter transfers your configuration data to the module using a BTW.

FlexBus

Your ladder program instructs the adapter to perform a BTR of the values and stores them in a data table.

The adapter module determines that the transfer was made without error and input values are within specified range.

Your ladder program can use and/or transmit the data (if valid) before it is overwritten by the transfer of new data in a subsequent transfer.

Your ladder program performs BTWs to the module when you power it up, and any time you wish to reconfigure the module.

External devices transmit frequency signals to the module.

The module converts frequency signals into integer format and stores these values until the adapter requests their transfer.

1794-ACN15 1794-ACNR15 1794-ACNR15K 1794-ADN 1794-AENT 1794-APBDPV1 1794-ASB 1794-APB

Adapter

1794-AENT shown

Typical Communication between a FLEX I/O Module and an Adapter

Publication 1794-6.5.11 - September 2011

Overview of the Frequency Input Module 5

Bridge

PanelView Station

Ethernet

PC running controller and Rockwell Automation configuration software

1794 Adapter 1794 FLEX I/O module

FLEX System

45567

ATTENTION

A broader view of how the FLEX I/O module interfaces with the different elements in a Logix system is shown in the sample illustration below.

Typical Applications

In this example, the FLEX I/O module communicates with the controller through the adapter. The controller can produce and consume tags. It can initiate MSG instructions that send and receive data or configure devices. Configuration of devices and the network is done through the personal computer running the controller and configuration software.

To learn about the steps to configure your FLEX I/O module, see Configure Your FLEX I/O Module with RSLogix 5000 Software on page 29.

The following publications provide more information about EtherNet/IP, and ControlNet modules in a Logix5000 system:

•EtherNet/IP Modules in Logix5000 Control Systems, publication E

NET-UM001

•ControlNet Modules in Logix5000 Control Systems, publication CNET-UM001

You can use the frequency input modules in power management, automotive, food and beverage, and oil and gas industries for various flow and/or turbine metering applications. Some sample applications include:

• turbine shaft speed monitoring

• automotive paint booths

• brewery flow monitoring

• petrochemical flow and custody transfer

Publication 1794-6.5.11 - September 2011

6 Overview of the Frequency Input Module

Channel 0

Channel 1

Frequency Input (F0) Gate Input (G0)

Frequency Input (F1) Gate Input (G1)

Frequency Input (F0-F1) – you connect your input device to this input (ac, proximity sensors switch, magnetic, vortex )

Gate Input (G0-G1) – you connect your input device to this input (ac, proximity sensors switch, magnetic, vortex )

used to determine direction – CW or CCW

2 input channels

FREQ

GATE

FREQUENCY INPUT 2 CHANNEL

1794-IJ2

Allen-Bradley

F0F

FREQ GATE

1F 1 F

OUT

45557

Input Capabilities

The frequency module has 2 input channels (mode dependent). Each of the 2 input channels may accept these input signals:

• magnetic pickup – 500 mV…28V AC peak (optional 50 mV…28V AC peak for increased signal sensitivity)

• proximity probe inputs

– compatible with Bently Nevada 3300 – 5 mm (0.197 in.) and 8 mm

(0.315 in.) – proximity transducer systems

– provides 1 isolated 24V DC power supply (2 channels rated at 30 mA

each) to power external devices

– vortex flowmeter – 6V and 3V

You configure the 2 input channels for your specific application(s). Each input channel has two input selections:

Publication 1794-6.5.11 - September 2011

Modes of Operation

Overview of the Frequency Input Module 7

Selecting the Modes of Operation

You configure the frequency input module for these modes of operation:

Mode Use this mode to Indicators /

Alarms

Frequency and % Full Scale

Frequency and Acceleration •Monitor the frequency of an input with high

•Monitor the frequency of an input with high accuracy (for example, shaft)

•Monitor the percentage of full scale frequency

•Operate frequency alarm (% full scale)

•Scale the frequency

•Monitor the direction of shaft rotation

•Wire-off alarm with DC devices

•Missing pulse alarm

accuracy (for example, shaft)

•Monitor the acceleration (rate of speed change)

•Operate acceleration alarm (rate of change)

•Scale the frequency

•Monitor the direction of shaft rotation

•Wire-off alarm with DC devices

•Missing pulse alarm

x x

Scaler / Values

Output Capabilities

The frequency input module has 2 assignable outputs. These outputs are designed for applications that require fast response. The outputs:

• are current sourcing at 10…31.2V DC (1 A maximum per output)

• are electrically fused (current limited to 3 A)

• can be assigned to the associated input channel with user-selectable frequency and acceleration values

• are isolated – this lets you use two separate external power supplies if desired (one for output 0 and one for output 1)

Implementing Application Features

You can use the module to implement programmable application features that are usually initiated by your controller processor. This frees up the controller

Publication 1794-6.5.11 - September 2011

8 Overview of the Frequency Input Module

processor to do other tasks and helps increase the overall throughput of your controller system.

Application Features

Feature Mode Purpose Alarm is ON when

Frequency alarm Frequency alarm

selected

Acceleration alarm Acceleration alarm

selected

Scaling % full scale and

acceleration

Activate alarm when calculated or scaled frequency is higher than user-specified frequency value.

Activate acceleration alarm when acceleration is greater than user-specified acceleration value.

Multiply and/or divide frequency by scalar Frequency > User-specified scaled

Frequency > user-specified value

| Acceleration | > user-specified value

frequency value

How Frequency Is Calculated

The following paragraphs explain the operation of the frequency input module algorithm and its modifying parameters.

Frequency Calculation

Frequency is determined by a general algorithm which can be modified by user-defined parameters. In its simplest form, the algorithm employs the user-defined Minimum Sampling Time to set a window in which to count pulses to determine the frequency. At least two pulses are required within the sample window. Frequency is determined by storing the time the first pulse occurred and then continually storing and updating the time of subsequent pulses, along with the number of pulses encountered. When the window expires, the frequency is calculated and the procedure repeats. The sequence and formula for determining frequency are shown below.

Publication 1794-6.5.11 - September 2011

Overview of the Frequency Input Module 9

Missing pulse alarm would be reported after 2 s, if no pulse occurs

Frequency reported at end sampling time

Pulses counted

T2 - T1

pulses counted

First pulse in window, T1 time stored

Last pulse in windowT2, update as each

pulse occurs

Minimum sampling time

Frequency input

pulses

45340

45341

Frequency reported at

first pulse in extended Time

2 - 1

T2 - T1

Missing pulse alarm is reported after 2 s, if no pulse occurs

Minimum sampling time Frequency input

pulses

2 = pulses counted

First pulse in window, T1 time stored

First pulse after window extended, T2 time stored

Sampling time extended to 2 s

Normal Mode Frequency Determination, at Least Two Pulses in Sampling Time

If only one pulse occurs within the sampling window, when the sample time has expired, the window is extended to 2 s to allow for a second pulse to occur. As soon as a second pulse occurs, the frequency is calculated and the procedures starts over. If no second pulse is detected, zero frequency is reported and a Missing Pulse Alarm is generated. The following figure depicts this scenario.

Normal Mode, Only One Pulse in Sampling Time, Sampling Time Extended

Publication 1794-6.5.11 - September 2011

10 Overview of the Frequency Input Module

Frequency reported at

number of pulses to

terminate reached

Pulses to terminate - 1

T2 - T1

Missing pulse alarm would be reported after 2 seconds, if no pulse occurs

pulses to terminate

Minimum sampling time

Frequency input

pulses

First pulse in window,

T1 time stored

T2, update as each pulse occurs

Number of pulses to terminate reached

45342

Termination on Number of Pulses

The normal mode is designed to provide wide bandwidth. However, it requires the full 2 seconds to report a missing pulse. Another user parameter, Number of Pulses to Terminate Sampling, is provided for scenarios where many pulses are expected within the sampling window, such that early determination of frequency is possible.

During normal operation, there is a sufficient number of pulses to prevent the module from entering the 2-second extension mode. Once the user-defined number of pulses is reached within the sampling window, the frequency is immediately reported.

If the sampling window has been extended to 2 seconds while waiting for a second pulse to occur, a situation which can occur during system startup, the module does not wait for the number of pulses to be reached. Instead, as soon as a second pulse occurs, the frequency is calculated based on the time between the 2 pulses, and the procedure starts over.

Termination on Number of Pulses

Missing Pulse Multiplier

Publication 1794-6.5.11 - September 2011

The last user parameter which is provided to modify the frequency algorithm is the Missing Pulse Multiplier. In this case, the user can set the number of Minimum Frequency Sampling Time windows allowed to extend the time to capture a second pulse, before reporting a Missing Pulse Alarm. The intent with this parameter is to allow a tradeoff of the bandwidth available with the response time to report a missing pulse. This mechanism is shown in the following figure.

Overview of the Frequency Input Module 11

Missing pulse multiplier

Frequency reported at first pulse in extended time

2 - 1

T2 - T1

Missing pulse alarm would be reported after last window, if no pulse occurs

Extended windows added one at time, until pulse occurs or multiplied windows exceeded

Minimum sampling time

2 = pulses counted

Possible extended window

Frequency input

pulses

First pulse in window,

T1 time stored

First pulse in an extended window, T2 time stored

45343

Direction Detection

Direction detection is accomplished by using the Frequency input, Gate input, and two sensors. The module expects to see a Low to High transition on the Frequency input, followed by a Low to High transition on the Gate input. This assumes both input polarity select bits are the same selection.

This corresponds to clockwise rotation. See illustration, Direction Detection – Principle of Operation, on page 12. If a Low to High transition occurs on the Gate input, followed by one on the Frequency input, the rotation is counterclockwise.

Publication 1794-6.5.11 - September 2011

12 Overview of the Frequency Input Module

45344

Direction Detection – Principle of Operation

Clockwise rotation

Chapter Summary

2 x M

Sensor 0

Sensor 1

Gate input

IJ2 module

Sensor 0 (F)

Sensor 1 (G)

Sensor 0 (F)

Sensor 1 (G)

Frequency input

Clockwise

Rotation

Counter

Clockwise

Rotation

In this chapter, you learned about the frequency input module, block transfer communication, and details of how the module functions.

Publication 1794-6.5.11 - September 2011

Chapter

ATTENTION

Install Your FLEX I/O Frequency Input Module

Overview

This chapter provides you with pre-installation requirements and instructions on how to install your FLEX I/O Frequency Input modules.

Topic Page

Before You Install Your Module 13 Power Requirements 13 Install the Module 14 Mount on a DIN Rail 14 Mount on a Panel or Wall 16 Mount the Frequency Input Module on the Terminal Base Unit 18 Wiring Information 20 Connect Wiring to the FLEX I/O Frequency Input Module 21 Connecting Wiring Using a 1794-TB3G, 1794-TB3GK or 1794-TB3GS

Terminal Base Unit Resolution and Accuracy 24 Examples of Wiring to a 1794-TB3G Terminal Base Unit 27 Chapter Summary 27

Before You Install

Before installing your frequency input module in the FLEX I/O system, you need to:

Your Module

• calculate the power requirements of all modules in each FLEX I/O system, and

• position the keyswitch on the terminal base.

This FLEX I/O module does not receive primary operational power from the backplane. 24V DC power must be applied to your module before installation. If power is not applied, the module position may appear to the adapter as an empty slot in your chassis.

Power Requirements

13 Publication 1794-6.5.11 - September 2011

The wiring of the terminal base unit is determined by the current draw through the terminal base. Make certain that the current draw does not exceed 10 A.

14 Install Your FLEX I/O Frequency Input Module

ATTENTION

Total current draw through the terminal base unit is limited to 10 A. Separate power connections may be necessary.

The frequency input module requires 30 mA at 5V DC from the FlexBus backplane.

Methods of wiring the terminal base units are shown in the illustration below.

Do not daisychain power or ground from the terminal base unit to any AC or DC digital module terminal base unit.

Install the Module

Installation of the frequency input module consists of:

• mounting the terminal base unit

• installing the module into the terminal base unit

• installing the connecting wiring to the terminal base unit

Mount on a DIN Rail

Do not remove or replace a terminal base unit when power is applied. Interruption of the FlexBus can result in unintended operation or machine motion.

Install the Terminal Base Unit

1. Remove the cover plug in the male connector of the unit to which you are connecting this terminal base unit.

Publication 1794-6.5.11 - September 2011

Install Your FLEX I/O Frequency Input Module 15

45319

45320

2. Check to make sure that the 16 pins in the male connector on the adjacent device are straight and in line so that the mating female connector on this terminal base unit will mate correctly.

Make certain that the female FlexBus connector is fully retracted into the base unit.

3. Position the terminal base at a slight angle and hooked over the top of the 35 x 7.5 mm DIN rail A (Allen Bradley part number 199-DR1; 46277-3).

4. Slide the terminal base over tight against the adapter, or proceeding terminal base. Make sure the hook on the terminal base slides under the edge of the adapter, or proceeding terminal base, and the FlexBus connector is fully retracted.

5. Rotate the terminal base onto the DIN rail with the top of the rail hooked under the lip on the rear of the terminal base. Use caution to make sure that the female FlexBus connector does not strike any of the pins in the mating male connector.

Publication 1794-6.5.11 - September 2011

16 Install Your FLEX I/O Frequency Input Module

45321

45322

6. Press down on the terminal base unit to lock the terminal base on the DIN rail. If the terminal base does not lock into place, use a screwdriver or similar device to open the locking tab, press down on the terminal base until flush with the DIN rail and release the locking tab to lock the base in place.

Gently push the FlexBus connector into the side of the adapter, or proceeding terminal base to complete the backplane connection.

Publication 1794-6.5.11 - September 2011

For specific wiring information, refer to the installation instructions for the module you are installing in this terminal base unit.

7. Repeat the above steps to install the next terminal base unit. Ensure that the cover of the FlexBus connector on the last terminal base unit is in place.

Mount on a Panel or Wall

Installation of a FLEX I/O system on a wall or panel consists of:

• laying out the drilling points on the wall or panel.

• drilling the pilot holes for the mounting screws.

• mounting the adapter mounting plate.

Install Your FLEX I/O Frequency Input Module 17

45323

Millimeters (inches)

45327

• installing the terminal base units and securing them to the wall or panel.

Use the mounting kit Cat. No. 1794-NM1 for panel or wall mounting.

1794-NM1 Mounting Kit

35.5

(1.4)

Description Description

1 Mounting plate for adapter 3 Terminal base unit (not included) 2 #6 Self-tapping screws 4 Adapter module (not included)

To install the mounting plate on a wall or panel:

1. Lay out the required points on the wall or panel as shown in the drilling

dimension drawing.

Drilling Dimensions for Panel or Wall Mounting

58.5 (2.3)

35.5

(1.4)

Millimeters

35.5 (1.4)

(Inches)

21 (0.83)

58.5 (2.3)

35.5 (1.4)

Publication 1794-6.5.11 - September 2011

+ 60 hidden pages

Rockwell Automation Allen-Bradley 1794-IJ2XT, Allen-Bradley 1794-IJ2K, Allen-Bradley 1794-IJ2 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Important User Information

Summary of Changes

New and Updated Information

Table of Contents

Preface

Who Should Use This Manual

Purpose of the Manual

About the Vocabulary

Related Documentation

Common Techniques Used in this Manual

Overview

The FLEX System

Type of Modules

Usage of the Frequency Input Module

The FLEX I/O Module in a Logix Control System

Typical Applications

Input Capabilities

Selecting the Modes of Operation

Output Capabilities

Implementing Application Features

How Frequency Is Calculated

Frequency Calculation

Termination on Number of Pulses

Missing Pulse Multiplier

Direction Detection

Chapter Summary

Overview

Power Requirements

Install the Module

Mount on a DIN Rail

Mount on a Panel or Wall