Allen-Bradley 1771-OFE User manual

Analog Output Module
Cat. No. 1771OFE
User Manual
Allen-Bradley PLCs

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: Identifies information about practices or
circumstances that can lead to personal injury or death, property
damage or economic loss.
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.
Important User Information

Summary of Changes
SI
Summary of Changes
This release of the publication contains updated information from the last
release.
Updated Information
This manual has been revised and reformatted to make the manual more
usable.
To help you find new and updated information in this release of the
publication, we have included change bars as shown to the right of this
paragraph.
Summary of Changes
Allen-Bradley PLCs

Summary of Changes SI . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preface P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual's Purpose P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audience P1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vocabulary P1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual Organization P1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Related Products P2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Product
Compatibility P2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overview of the Analog Output Module 11. . . . . . . . . . . . . . .
Chapter Objectives 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Description 11
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How Analog Modules Communicate with Programmable Controllers 12
Accuracy 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Summary 13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Installation 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Objectives 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Before Y
ou Install Y our Analog Module 21. . . . . . . . . . . . . . . . . . . . .
Calculating Power Requirements 21
. . . . . . . . . . . . . . . . . . . . . . . . .
Determine Module Location in the I/O Chassis 22
. . . . . . . . . . . . . . .
Setting Module Configuration Jumpers 22
. . . . . . . . . . . . . . . . . . . . .
Connecting Wiring 29
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interpreting the Indicator Lights 211
. . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Summary 211
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Configuration 31. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Objectives 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring Your Module 31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Word 33
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Default
Configuration 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Format 34
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scaling 36
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Procedure for Configuring Your Module 39
. . . . . . . . . . . . . . . . . . . .
Chapter Summary 39
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents

Table of Contentsii
Module Programming 41. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Objectives 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Block Transfer with the Analog Output Module 41
. . . . . . . . . . . . . . .
Block Transfer Programming Formats 41
. . . . . . . . . . . . . . . . . . . . .
Block Transfer Programming  PLC2 Family Processors Only 42
. . . .
Block Transfer Programming  PLC3 Family Processors Only 46
. . . .
Block Transfer Programming  PLC5 Family Processors Only 48
. . . .
Other Programming Considerations 410
. . . . . . . . . . . . . . . . . . . . . . .
System Expansion Recommendations  PLC2 Processors Only 413
. .
Chapter Summary 413
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Module Status and Input Data 51. . . . . . . . . . . . . . . . . . . . . .
Chapter Objectives 51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reading Data from the Module 51
. . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter Summary 52
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Calibrating Y our Output Module 61. . . . . . . . . . . . . . . . . . . . .
Chapter Objectives 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tools and T
est Equipment 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Calibrating Your Module 61
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage
Output V ersion (1771OFE1) 62. . . . . . . . . . . . . . . . . . . . . .
Current
Output V ersion (1771OFE2) 66. . . . . . . . . . . . . . . . . . . . . .
Current
Output V ersion (1771OFE3) 610. . . . . . . . . . . . . . . . . . . . . .
Chapter Summary 612
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostics and Troubleshooting 71. . . . . . . . . . . . . . . . . . .
Chapter Objectives 71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interpreting the Indicator Lights 71
. . . . . . . . . . . . . . . . . . . . . . . . . .
Read Block Transfer Status Words 72
. . . . . . . . . . . . . . . . . . . . . . .
Chapter Summary 73
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications A1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Block Transfer with MiniPLC2 and PLC2/20 Processors B1.
Multiple GET Instructions B1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the Block Length (Multiple GET Instructions Only) B3
. . . . . . .
Data Table Formats C1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4Digit Binary Coded Decimal (BCD) C1. . . . . . . . . . . . . . . . . . . . . .
Signedmagnitude Binary C2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Two's Complement Binary C3
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Allen-Bradley PLCs

Preface
P-1
Preface
This manual shows you how to use the analog output module with an
Allen-Bradley programmable controller. It describes methods for
installing, programming, calibrating, and troubleshooting your module.
To make efficient use of your module, you must be able to program and
operate an Allen-Bradley programmable controller. In particular, you must
be able to program block transfer instructions.
In this manual we assume that you know how to do this. If you do not,
refer to the appropriate programming and operations manual for the
processor that you are using.
In this manual we refer to the:
Analog Output Module (cat. no. 1771-OFE) as the “output module”
Programmable Controller as the “processor” or “controller.”
The manual is divided into seven chapters. The following chart shows
each chapter with its corresponding title and a brief overview of the topics
covered in that chapter.
Chapter Title Topics Covered
1Introduction and
Product Description
Description of the module, including general and
hardware features. How modules communicate with
programmable controllers
2Module Installation Power requirements, keying, module location and hard
ware configuration
3Module Configuration Software configurations, output range selection, data
format and data scaling
4Module Programming
Writing data to the module, and other programming
considerations (default block length, block transfer
boundary word, and watchdog timer)
5Module Status and Input Data Reading data from the module
6 Calibration Calibration Procedures
7Diagnostics and Troubleshooting Troubleshooting Guide for Problem Diagnosis
Manual's Purpose
Audience
Vocabulary
Manual Organization

Preface
P-2
Appendices Title
A Specifications
BBlock Transfer with MiniPLC2 and PLC2/20 Processors
CData Formats
You can install your output module in any system that uses Allen-Bradley
programmable controllers that have block transfer capabilities and the
1771 I/O structure.
For more information on your programmable controllers, contact your
nearest Allen-Bradley office.
The 1771-OFE module can be used with any 1771 I/O chassis.
Communication between the discrete analog module and the processor is
bidirectional; the processor block-transfers output data through the output
image table to the module and block-transfers input data from the module
through the input image table. The module also requires an area in the data
table to store the read block transfer data and write block transfer data. I/O
image table use is an important factor in module placement and addressing
selection. Compatibility and data table use is listed in the following table.
Table P.A
Compatibility
and Use of Data T able
Use of Data Table Compatibility
Catalog
Number Input
Image
Output
Image
Read
Block
Write
Block
Addressing Chassis
Number
Image
Bits
Image
Bits
Block
Words
Block
Words 1/2Slot 1Slot 2Slot
Chassis
Series
1771OFE 8 8 5 13 Y Y Y A, B
A = Compatible with 1771A1, A2, A4
B = Compatible with 1771A1B, A2B, A3B, A3B1, A4B
Y = Compatible without restriction.
You can place your module in any I/O module slot of the I/O chassis.
You can put two output modules in the same module group.
Do not put the module in the same module group as a discrete high
density module.
Avoid placing output modules close to ac modules or high voltage dc
modules.
For a list of publications with information on Allen-Bradley programmable
controller products, consult our publication index (SD499).
Related Products
Product Compatibility
Related Publications
Allen-Bradley PLCs

Chapter 1
1-1
Overview of the Analog Output Module
In this chapter, you will read about:
module features
how analog modules communicate with programmable controllers
module output ranges
The Analog Output Module (cat. no. 1771-OFE) is an intelligent block
transfer module that converts binary or four-digit BCD values (supplied by
your processor) to analog signals at its four module outputs. The module
accomplishes the data transfer with block transfer programming.
Block transfer write (BTW) programming moves up to 13 words of data
from the processor to the module for digital to analog (D/A) conversion in
one program scan. This information is converted to analog signals and is
sent to the appropriate output channels.
A block transfer read (BTR) moves five words of data from the module to
the processor data table, if desired, for diagnostic purposes. The BTR is
discussed in Chapter 7, “Diagnostics and Troubleshooting.”
The module has a scaling feature that converts data sent to the module in
engineering units to the proper analog signals.
You may connect up to four analog output devices--such as valve
positioners, motor speed controllers, signal converters or recorders--to the
analog output module’s four channels. All analog output device inputs
should conform to the voltage or current ratings of each module
output channel.
Module Features
In the programmable controller system, the analog output module provides
the following functions:
four individually isolated differential outputs
selectable scaling to engineering units
selectable data format
selectable voltage ranges (1771-OFE1 only)
no external power required--power is drawn from the 1771 I/O chassis
backplane.
requires only one I/O slot
Chapter Objectives
Module Description

Overview of the Analog Output Module
Chapter 1
1-2
Output Ranges
There are three versions of the analog output module:
Catalog Number Module Output Output Range
1771OFE1 Voltage
15V dc
010V dc
+10V dc
Selected by
configuration
jumpers
1771OFE2 Current 420mA Factory set
1771OFE3 Current 050mA Factory set
The voltage version (1771-OFE1) voltage output range is selected with
configuration jumpers in the module:
Note: The 1771-OFE1 is shipped with the selection jumpers in the
+10V position.
The current output versions (1771-OFE2 and -OFE3) are factory set.
The processor 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 processor send output
values to the module, establish the module’s mode of operation
(Figure 1.1) and receive status information from the module.
Figure 1.1
Communication
Between Processor and Module
+
–
2
13
To analog output devices
BTW
Programmable
Controller Analog Output Module
Cat. No. 1771OFE
12876
BTR
4
5
1. The processor transfers your configuration and output data to the
module via a block transfer write instruction.
How Analog Modules
Communicate with
Programmable Controllers
Allen-Bradley PLCs

Overview of the Analog Output Module
Chapter 1
1-3
2. The module converts the data into proportional voltage or current
outputs.
3. These module outputs drive external analog devices.
4. When instructed by your ladder program, the processor performs a
read block transfer of output values and module status.
5. The processor and module determine that the transfer was made
without error.
6. Your ladder program can use and/or move the data (if valid) before it
is written over by the transfer of new data in a subsequent transfer.
The accuracy of your output module is described in Appendix A.
In this chapter you read about the functional aspects of the output module
and how the module communicates with the programmable controller.
Accuracy
Chapter Summary