Allen-Bradley FLEX I/O 1794-IJ2 User manual

User
Manual
FLEX I/O
Frequency
Input Module
(Cat. No. 1794-IJ2)
Allen-Bradley
Allen-Bradley Replacements

Important User Information Because of the variety of uses for the products described in this
publication, those responsible for the application and use of this control
equipment must satisfy themselves that all necessary steps have been
taken to assure that each application and use meets all performance and
safety requirements, including any applicable laws, regulations, codes and
standards.
The illustrations, charts, sample programs and layout examples shown in
this guide are intended solely for example. Since there are many variables
and requirements associated with any particular installation,
Allen-Bradley does not assume responsibility or liability (to include
intellectual property liability) for actual use based upon the examples
shown in this publication.
Allen-Bradley publication SGI-1.1, “Safety Guidelines For The
Application, Installation and Maintenance of Solid State Control”
(available from your local Allen-Bradley office) describes some important
differences between solid-state equipment and electromechanical devices
which should be taken into consideration when applying products such as
those described in this publication.
Reproduction of the contents of this copyrighted publication, in whole or
in part, without written permission of Allen-Bradley Company, Inc. is
prohibited.
Throughout this manual we make notes to alert you to possible injury to
people or damage to equipment under specific circumstances.
Attention helps you:
• identify a hazard
• avoid the hazard
• recognize the consequences
Important: Identifies information that is especially important for
successful application and understanding of the product.
Important: We recommend you frequently backup your application
programs on appropriate storage medium to avoid possible
data loss.
DeviceNet, DeviceNetManager, and RediSTATION are trademarks of Allen-Bradley Company, Inc.
PLC, PLC-2, PLC-3, and PLC-5 are registered trademarks of Allen-Bradley Company, Inc.
Windows is a trademark of Microsoft.
Microsoft is a registered trademark of Microsoft
IBM is a registered trademark of International Business Machines, Incorporated.
All other brand and product names are trademarks or registered trademarks of their respective companies.
!
ATTENTION: Identifies information about practices or
circumstances that can lead to personal injury or death,
property damage, or economic loss.

Publication 1794-6.5.11 - November 1997
Preface
Using This Manual
Purpose of this Manual This manual shows you how to use your FLEX I/O 2 input frequency
module with Allen-Bradley programmable controllers. The manual helps
you install, program and troubleshoot your module.
Audience You must be able to program and operate an Allen-Bradley programmable
controller to make efficient use of your FLEX I/O module. In particular,
you must know how to program block transfers.
We assume that you know how to do this in this manual. If you do not,
refer to the appropriate programming and operations manual before you
attempt to program your modules.
Vocabulary In this manual, we refer to:
– the frequency input module as the “input module”
– the Programmable Controller as the “controller”
Manual Organization This manual is divided into five chapters. The following chart lists each
chapter with its corresponding title and a brief overview of the topics
covered in that chapter.
Chapter Title Contents
1Overview ofFLEXI/O and Frequency
Input modules Describes FLEX I/O frequency input modules, features, and how they function
2How to Install Your Frequency Input
Module How to install and wire the module
3Module Programming Explains block transfer programming, sample programs
4Writing Configuration to and
Reading Status From with a Remote
I/O Adapter
Explains how to configure your modules and read status
information from your modules when using a remote I/O
adapter
5How Communication Takes Place
and I/O Image Table Mapping with
the DeviceNet Adapter
Explains how you communicate with your modules, and
how the I/O image is mapped when using a DeviceNet
adapter
Appendix Title Contents
ASpecifications Specifications for the frequency module
BSchematics Simplified schematics of frequency input module
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Publication 1794-6.5.11 - November 1997
-2 Using This Manual
Conventions We use these conventions in this manual:
For Additional Information For additional information on FLEX I/O systems and modules, refer to
the following documents:
In this manual, we show: Like this:
that there is more information about a topic
in another chapter in this manual
that there is more information about the
topic in another manual
Catalog
Number Voltage Description Publications
Installation
Instructions User Manual
1794 1794 FLEX I/O Product Data 1794-2.1
1794-ACN 24V dc ControlNet Adapter 1794-5.8
1794-ACNR 24V dc Redundant Media ControlNet Adapter 1794-5.18
1794-ACN15 24V dc ControlNet Adapter 1794-5.47
1794-ACNR15 24V dc Redundant Media ControlNet Adapter 1794-5.48
1794-ADN 24V dc DeviceNet Adapter 1794-5.14 1794-6.5.5
1794-ASB/C 24V dc Remote I/O Adapter 1794-5.50 1794-6.5.9
1794-ASB2/B 24V dc 2-Slot Remote I/O Adapter 1794-5.44 1794-6.5.13
1794-APB 24V dc Profibus Adapter 1794-5.40 1794-6.5.6
1794-IB8 24V dc 8 Sink Input Module 1794-5.30
1794-OB8 24V dc 8 Source Output Module 1794-5.31
1794-IB16 24V dc 16 Sink Input Module 1794-5.4
1794-OB16 24V dc 16 Source Output Module 1794-5.3
1794-IV16 24V dc 16 Source Input Module 1794-5.28
1794-OV16 24V dc 16 Sink Output Module 1794-5.29
1794-OB8EP 24V dc 8 Electronically Fused Output Module 1794-5.20
1794-IB8S 24V dc Sensor Input Module 1794-5.7
1794-IB10XOB6 24V dc 10 Input/6 Output Module 1794-5.24
1794-IE8 24V dc Selectable Analog 8 Input Module 1794-5.6 1794-6.5.21794-OE4 24V dc Selectable Analog 4 Output Module 1794-5.5
1794-IE4XOE2 24V dc 4 Input/2 Output Analog Module 1794-5.15
Table continued on next page

Publication 1794-6.5.11 - November 1997
Using This Manual -3
Summary This preface gave you information on how to use this manual efficiently.
The next chapter introduces you to the frequency module.
1794-OF4 24V dc 4 Output Isolated Analog Module 1794-5.37 1794-6.5.81794-IF4 24V dc 4 Input Isolated Analog Module 1794-5.38
1794-IF2XOF2 24V dc 2 Input/2 Output Isolated Analog Module 1794-5.39
1794-IR8 24V dc 8 RTD Input Analog Module 1794-5.22 1794-6.5.4
1794-IT8 24V dc 8 Thermocouple Input Module 1794-5.21 1794-6.5.7
1794-IRT8 24V dc 8 Thermocouple/RTD Input Module 1794-5.50 1794-6.5.12
1794-IJ2 24V dc 2 FrequencyInput Module 1794-5.49 1794-6.5.11
1794-IA8 120V ac 8 Input Module 1794-5.9
1794-OA8 120V ac Output Module 1794-5.10
1794-TB2
1794-TB3 2-wire Terminal Base 3-wire Terminal Base 1794-5.2
1794-TBN Terminal Base Unit 1794-5.16
1794-TBNF Fused Terminal Base Unit 1794-5.17
1794-TB3T Temperature Terminal Base Unit 1794-5.41
1794-TB3S Spring Clamp Terminal Base Unit 1794-5.42
1794-TB3TS Spring Clamp Temperature Base Unit 1794-5.43
1794-TB3G Terminal Base Unit 1794-5.51
1794-TB3GS Spring Clamp Terminal Base Unit 1794-5.59
1794-CE1, -CE3 Extender Cables 1794-5.12
1794-NM1 Mounting Kit 1794-2.13
1794-PS1 24V dc Power Supply 1794-5.35
Catalog
Number Voltage Description Publications
Installation
Instructions User Manual
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-4 Using This Manual

Table of Contents
Publication 1794-6.5.11 - November 1997
Overview of the Frequency
Input Module Chapter 1
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
How You Use the Frequency Input Module . . . . . . . . . . . . . . . . . . . . . 1-1
What the Frequency Input Module Does. . . . . . . . . . . . . . . . . . . . . . . . 1-2
Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Input Capabilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Selecting the Mode(s) of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Output Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Implementing Application Features . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
How Frequency is Calculated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Frequency Calculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Termination on Number of Pulses. . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Missing Pulse Multiplier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-7
Direction Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
How to Install Your Frequency
Input Module Chapter 2
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Before You Install Your Input Module . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
European Union Directive Compliance. . . . . . . . . . . . . . . . . . . . . . . . . 2-1
EMC Directive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Low Voltage Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Wiring the Terminal Base Units (1794-TB3G shown) . . . . . . . . . . . 2-3
Installing the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Mounting the Terminal Base Unit on a DIN Rail . . . . . . . . . . . . . . . 2-4
Panel/Wall Mounting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Mounting the Frequency Input Module on the Terminal Base Unit . 2-7
Connecting Wiring for Your Frequency Input Module. . . . . . . . . . . . . 2-9
Connecting Wiring using a 1794-TB3G and –TB3GS
Terminal Base Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Wiring connections for the 1794-IJ2 Frequency Input Module . . 2-11
Examples of Wiring to a 1794-TB3G Terminal Base Unit. . . . . . . 2-12
Module Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
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toc–ii Table of Contents – FLEX I/O Frequency Input Module
Publication 1794-6.5.11 - November 1997
Programming Your Frequency
Input Module Chapter 3
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Enter Block Transfer Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
PLC-2 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
PLC-3 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
PLC-5 Family Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
PLC-5/250 Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Writing Configuration to and
Reading Status from Your
Module with a Remote I/O
Adapter
Chapter 4
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Configuring Your Frequency Input Module . . . . . . . . . . . . . . . . . . . . . 4-1
Reading Data From Your Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Mapping Data for the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Frequency Input Module (1794-IJ2) Image Table Mapping . . . . . 4-2
Block Transfer Read Word Assignments for the Frequency
Input Module (1794-IJ2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Bit/Word Definitions for Block Transfer Read Words for the
Frequency Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Block Transfer Write Word Assignments for the Frequency
Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Bit/Word Definitions for the Block Transfer Write Words for the
Frequency Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
How Communication Takes
Place and I/O Image Table
Mapping with the DeviceNet
Adapter
Chapter 5
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
About DeviceNetManager Software . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Polled I/O Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Adapter Input Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
System Throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Mapping Data into the Image Table . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Frequency Input Analog Module (1794-IJ2) Image Table Mapping 5-3
Block Transfer Read Word Assignments for the Frequency
Input Module (1794-IJ2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Block Transfer Write Word Assignments for the Frequency
Input Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Bit/Word Descriptions for the Frequency Input Module
(1794-IJ2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Defaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13

Table of Contents – FLEX I/O Frequency Input Module toc–iii
Publication 1794-6.5.11 - November 1997
Troubleshoot the Frequency
Input Module Chapter 6
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Status Indicators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Diagnostic Bits in Word 5 of the BTR File. . . . . . . . . . . . . . . . . . . . 6-3
What’s Next. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Specifications Appendix A
What This Appendix Contains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Resolution and Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4
Schematics Appendix B
What This Appendix Contains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
Input Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
Frequency Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
Gate Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1
Output Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-2
Digital Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-2
DC to DC Converters (24V dc power supplies) . . . . . . . . . . . . . . . .B-3
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Publication 1794-6.5.11 - November 1997
Chapter 1
Overview of the Frequency
Input Module
What This Chapter
Contains Read this chapter to familiarize yourself with the 1794-IJ2 module.
How You Use the
Frequency Input Module The 1794-IJ2 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. The
module accepts and returns binary data.
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.
The module’s primary use 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 Vdc @ 15 mA max) is supplied
by the I/O module.
For information on See page
How You Use the Module . . . . . . . . . . . . . . . . . . . . . . . . 1-1
What the Frequency Input Module Does . . . . . . . . . . . . . 1-2
Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Input Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Selecting the Mode(s) of Operation. . . . . . . . . . . . . 1-4
Output Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Implementing Application Features. . . . . . . . . . . . . 1-5
How Frequency is Calculated 1-5