Allen-Bradley CompactBlock LDX 1790D-4T0, User Manual

Page: 41 / 112

Publication 1790-UM003A-EN-P
Module Data, Status, and Channel Configuration for DeviceNet 3-11
Figure 3.10 Type N Thermocouple
Cold Junction
Compensation
When using thermocouples, cold junction compensation (CJC) is required
at the termination of the thermocouple wire. A cold junction can be
accomplished different ways:
•
Use the built-in CJC
•
Enter an estimated temperature
•
Use an external CJC
Entering an estimated temperature may be the least accurate way for CJC
compensation. Using external CJC is the most expensive way. Using the
compensation built into the module provides the easiest way for CJC.
Built-in module cold junction linearization may be enabled or disabled. If
enabled, the proper cold junction compensation value will be applied to
the thermocouples. If disabled, the built-in cold junction temperature
data is not applied to the inputs. In this case, a cold junction value can be
added using the Cold Junction Offset parameter.
AB Drives