Hardware reference guide

I/O Modules
35013379 11/2011 499
4. Connections marked Not Used are not electrically connected within the module.
These points are used as a thermal link to ambient air. They are not
recommended as electrical tie points as this could affect the accuracy of cold
junction compensation.
5. The 140 CFA 040 00 CableFast block can be used. However it can create a
temperature variation up to 35.6 ° F (2 ° C).
Diagnostic
1. All TC ranges have an open TC detect and upscale output. This results in a
reading of 7FFF hexadecimal (32767 decimal) when an open TC is detected
Using Cold Junction Compensation (CJC)
For temperature measurements, the 140 ATI 030 00 provides an internal CJC.
However, a remote CJC can be used with the following TC types: J,K and T. The TC
must be connected to Channel.
NOTE:
Recommendation when using remote CJC:
z To obtain the best accuracy when using a remote CJC, connect it as close as
possible from the 140 ATI 030 00 module.
z The distance between the external CJC and the module affects the temperature
measurement accuracy.
z The usage of CableFast with a remote CJC is not recommended.
The following diagram shows how to connect a remote CJC using a temperature
compensation on the 140 ATI 030 00: