User Manual

1 Publication 1746-UM010B-EN-P - April 2001
Chapter 7
Calibrating the Module
About the Procedure
Calibrate the module after the first 6 months of operation. Then check
the calibration and re-calibrate only if necessary once a year.
Use this procedure to store calibration values for each channel in
EEPROM. Calibration sets channel accuracy at 0.05% of full range
regardless of channel circuit tolerances. You can calibrate the input
channels individually or in groups. The thermocouple/mV operation
of all channels is suspended during calibration.
Calibration Codes and Status
Use the following format for entering calibration code words and
reading calibration status bits. Enter calibration values in hexadecimal.
You read channel status bits at different steps in the calibration
procedure, one bit for each channel you are calibrating.
Use Word 14 (Output Image) for entering calibration codes
Use Words 4 and 5 (Input Image) for reading calibration status
Code Word 5
Status Word 4
Status Word 5
Calibration codes in Hex
Channel status during
calibration
Channel status at
completion of calibration
15 12 11 08 07 04 03 00
15 12 11 08 07 04 03 00
15 12 11 08 07 04 03 00
1001
OK status bits (1=OK) for channels 3,2,1,0
(high-end calibration) @
OK status bits (1=OK) for channels 3,2,1,0
(low-end calibration) @
OK status bits (1=OK) for channels 3,2,1,0
(low-end calibration) @
Channel status words 6 and 7 display “CAL4” during calibration
@ Reads F Hex if all four channels are OK