Spectrum Controls 1769sc-IF8u - Manual (Page 40)

30 Compact IO ™ Universal Input module
NOTE: When using an ungrounded thermocouple, the shield must be
connected to ground at the module end.
!
IMPORTANT: When using grounded and/or exposed thermocouples
that are touching electrically conductive material, the ground potential
between any two channels cannot exceed ±10V dc, or temperature readings
will be inaccurate.
Cold Junction
Compensation
To obtain accurate readings from channels configured for
thermocouple, the cold junction temperature (temperature at the
module’s terminal junction between the thermocouple wire and the
input channel) must be compensated. One cold junction compensating
thermistor has been integrated into the removable terminal block. This
thermistor must remain installed to retain accuracy. If the thermistor
assembly is accidentally removed, re-install it by connecting it across
the CJC terminals.
Note: Thermocouple accuracy can differ between channels on the
terminal block. Channels that are physically located further from the
CJC sensor are more likely to exhibit a temperature offset. The figure
below shows the CJC accuracy for each channel.
Note: Using a remote terminal block can improve CJC accuracy.
When using remote terminal blocks, remove the CJC sensor from the
module RTB and mount it on the remote terminal block. Be sure to
use shielded twisted pair wire between the module and the remote