Performing manual calibration – Rockwell Automation 1771-IR Series D RTD Input Module User Manual User Manual
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6–5
Calibrating Your Module
Publication 1771Ć6.5.129 - March 2000
4. Queue BTRs to monitor for gain calibration complete and
channels which may not have calibrated successfully.
Save Calibration Values
If any ”uncalibrated channel” bits (bits 10–15 of BTR word 9) are
set, a save cannot occur. Auto–calibration should be performed
again, starting with offset calibration. If the module has a faulty
channel, the remaining functioning channels can be calibrated by
inhibiting calibration on the faulty channel.
The module can be run with the new calibration values, but will lose
them on power down. To save these values, proceed as follows:
1. Request a ”save to EEPROM” by setting bit 02 in BTW word 15
and sending the BTW to the module (see below).
Write Block Transfer Word 15
Word Bit
17
16 15 14 13 12 11 10 07 06 05 04 03
02
01
00
Inhibit Calibration on Channel
Requested Auto-Calibration
Word 15
Set these
bits to 0
6
5
4
3
2
1
Set these bits to 0
Requested
Save
Values
Requested
Gain Cal.
Requested
Offset Cal.
2. Queue BTRs to monitor for ”save complete”, ”EEPROM fault”
and ”calibration fault.” An EEPROM fault indicates a
nonoperative EEPROM; a calibration fault indicates at least one
channel was not properly offset or gain calibrated and a save did
not occur.
Note: During normal operation, make sure bits 00, 01 and 02 of
BTW word 15 are zero (0).
You calibrate each channel by applying a precision resistance across
each channel, comparing correct with actual results, and entering
correction into the corresponding calibration word for that channel.
The correction takes affect after it is transferred to the module by the
corresponding BTW instruction in your ladder diagram program.
Always start with offset adjustment followed by gain adjustment.
Before calibrating the module, you must enter ladder logic into
processor memory, so that you can initiate write block transfers to
the module, and the processor can read inputs from the module.
Performing Manual
Calibration