Rockwell Automation 1769-IT6 Compact I/O Thermocouple/mV Input Module - Manual (Page 16)

16 Compact I/O Thermocouple/mV Input Module
Publication 1769-IN026C-EN-P - February 2010
Cold-junction Compensation (CJC)
You must compensate for the cold-junction temperature—the temperature at the module’s
terminal junction between the thermocouple wire and the input channel—to obtain accurate
readings from each of the channels. Two cold-junction compensating thermistors have been
integrated in the terminal block, as shown on
page 15 .
ATTENTION
Do not remove or loosen the cold-junction compensating thermistor assemblies on the
terminal block. Both thermistor assemblies are critical to be sure of accurate
thermocouple input readings at each channel. If either CJC sensor is removed, the
open-circuit detection bit (OC6 or OC7) and the general status bit (S6 or S7) are set.
The module will continue to operate, but with reduced accuracy.