Rockwell Automation 1771-IR Series D RTD Input Module User Manual - Manual (Page 39)

Chapter
6
Publication 1771Ć6.5.129 - March 2000
Calibrating Your Module
In this chapter we tell you how to calibrate your modules.
In order to calibrate your input module you will need the following
tools and equipment:
Tool or Equipment Description Model/Type Available from:
Industrial Terminal and
Interconnect Cable
Programming terminal for A-B
family processors
Cat. No. 1770-T3 or Cat. No.
1784-T45, -T50, etc.
Allen-Bradley Company
Highland Heights, OH
Precision Resistors 1.00 ohm, 1% (quantity of 6) CMF-65-0010-F-T-0 Dale
402.0 ohm, 0.01% (quantity of 6) MAR6-T16-402-.01% TRW
You must calibrate the module in an I/O chassis. The module must
communicate with the processor and industrial terminal.
Before calibrating your module, you must enter ladder logic into the
processor memory, so that you can initiate BTWs to the module, and
the processor can read inputs from the module.
Calibration can be accomplished using either of two methods:
•
auto–calibration
•
manual calibration
Auto–calibration calibrates the input by generating offset and gain
correction values and storing them in EEPROM. These values are
read out of EEPROM and placed in RAM memory at initialization of
the module.
The auto–calibration routine operates as follows:
– Whenever a block transfer write (BTW) is performed to the
module (any time after the module has been powered up),
it interrogates word 15 for a request for auto–calibration.
– The request can be for the following: offset calibration,
gain calibration, save operation (save to EEPROM).
When using auto–calibration, write transfer calibration words 9
through 14 must contain zeroes.
Chapter Objective
Tools and Equipment
Calibrating your Input
Module
About Auto-calibration