Rockwell Automation 1771-IXE/D Thermocouple/Millivolt Input Module User Manual - Manual (Page 45)

6–5 Module Calibration
Publication 1771Ć6.5.130 Ć May 1999
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 28
and sending the BTW to the module. Refer to Table 6.A.
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.
You calibrate each channel by applying a precision voltage to the
input terminals, 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.
Write transfers will contain calibration values in words 20 through
27 for the channel you are calibrating.
Use a precision voltage source, such as Data Precision 8200 or
equivalent, for your calibration input voltage.
Setting Channel Offset Calibration
1. Select the millivolt range and binary data format. (BCD could be
used, but it cannot display values larger than 100mV required
during gain calibration.)
2. Apply 0.000 millivolts to the channel input as shown in
Figure 6.3.
Performing Manual
Calibration