Overview Of The Analog Output Module; Chapter Objectives; Module Description; How Analog Modules Communicate With Programmable Controllers 1 - Allen-Bradley 1771-OFE User Manual

Chapter Objectives

Module Description

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
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