1746-NT8 have problem

dear all.

Now, I use 1746-NT8, use K-type sensor and i config use oC. Some time 1746-NT8 display temperature 1370oC, but realtemp is 230oC. It have with all channel of module.Status led of module is OK. Have problem with 1746-NT8?.

Thanks.

Usually when a thermocouple card reads high scale like that, it's because of faulty wiring. TC wiring is critical, every problem I've ever had was due to a loose, corroded or improperly connected wiring termination. If you read up on the maitenance recommendations from the TC supplier, you will find that the wiring should be checked on a routine basis, this is often iqnored. That's one of the reasons's I seldom use TC's. I prefer RTD's, much more robust, and require very little maintenance.

You most likely have an open circuit, since it is reading max scale (1370 C) for a type K.

Other possibility is that you have a grounded T/C.

This module wants an ungrounded T/C

Dear all.
I replace other NT8. Temperature is OK. Can old NT8 failed. I can repair that NT8, What component can fault?.
Thanks.