Rockwell Automation 1746-BTM Barrel Temperature Control Module User Manual - Manual (Page 62)

Publication 1746-UM010B-EN-P - April 2001
7-2 Calibrating the Module
Calibration Procedure
To calibrate the module, you need a precision dc voltmeter and
precision power supply that can display and maintain a calibration
voltage to 1/1000 of a millivolt: at 0.000 mV and 90.000 mV.
For convenience, calibrate all four channels at the same time.
To prepare for the calibration:
•
Remove the thermocouple leads from the input terminals of the
channels that you want to calibrate.
•
Switch the SLC processor to run mode so it can execute the
calibration ladder logic.
To calibrate the module, follow this procedure:
1. With your programming terminal, enter calibration code 1001
Hex into output word 14.
2. Observe input words 0–3, 6 and 7.
– The module clears words 0-3. The module returns “CA14”
Hex in words 6 and 7.
3. Short circuit the pairs of input terminals for the channels you
want to calibrate. Make the jumper as short as possible.
4. With your programming terminal, enter calibration code 1002
Hex into output word 14.
5. Observe bits 0–3 in input word 4.
– If all the channels you are calibrating see zero voltage, the
module returns status–OK bits set, one bit for each channel (F
Hex for all four channels). Otherwise, the module returns
channel status bits set to zero.
6. Apply 90.000 mV to the pairs of input terminals, all in parallel,
for the channels you are calibrating. Use short leads.
7. With your programming terminal, enter calibration code 1004
Hex into output word 14.
8. Observe bits 4–7 in status word 4.
– If all channels being calibrating see 90.000 mV, the module
returns a status–OK bit set for each channel (F Hex for all
four channels). Otherwise, the module returns channel status
bits set to zero.