Rockwell Automation 1771-IR Series D RTD Input Module User Manual - Manual (Page 44)

6–6 Calibrating Your Module
Publication 1771Ć6.5.129 - March 2000
Words 9 through 14 in the write block transfer file are the module
calibration words. Word 9 corresponds to channel 1, word 10 to
channel 2, and so on. Each word is composed of two bytes: the upper
byte is for offset correction and the lower byte is for gain correction.
Refer to the table below.
Module Calibration Words
Word/Bit 17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
9 S Channel 1 Offset S Channel 1 Gain
10 S Channel 2 Offset S Channel 2 Gain
11 S Channel 3 Offset S Channel 3 Gain
12 S Channel 4 Offset S Channel 4 Gain
13 S Channel 5 Offset S Channel 5 Gain
14 S Channel 6 Offset S Channel 6 Gain
Enter the information for each byte in signed magnitude binary
format. In each byte, the most significant bit (bits 17, 7) is a polarity
bit. When the polarity bit is set (1), the module anticipates a negative
calibration value.
A negative calibration value means that your readings are too high
and you want to subtract a corrective amount from that reading.
A positive calibration value means that your readings are too low
and you want to add a corrective amount to that reading.
Important: If you have a spare field wiring arm. you may want to
temporarily switch it with the module’s present wiring
arm. You can use this spare arm for test purposes in
order to avoid disconnecting your RTD wiring.