XVAL zero in case of no physical connection


I am Using SNAP-AICTD card on rack with R2 controller.
I am facing the issue regarding XVAL.
My problem is when there is no physical connection on my channel at that time it shows some random numbers,is there any method to visualise the zero in XVAL when there is no physical connection.

On an ICTD module you should read about -273 degrees C with no connection. The sensors flow 1 uA/K, so open circuit would be 0uA, thus 0K which is -273 degrees C.

Best thing to do here is to have your logic check for an out of range value. 0 would not be a good value to represent a no connection.

You may also read 65536 (I think - and I also think this is configurable at the brain level), that usually means there is some sort of problem with the module/power supply.

Thanks phillip for response…
Same things applied to snap-aitm card??

Not the same, but similar. It will depend on what you have it configured for. If you have it set to measure mV, then you will get 0 with no connection. If you are using one of the temperature curves, then just check for out of range values like you would with an ICTD.

I have an AITM on my bench, if you would like me to check what values it returns for various probe settings on open circuit, let me know if you want me to check this.

If you can assist me for the same then it will be help me for the future configuration…

I’m getting -32768 when open circuit on the AITM, which is the 16 bit out of range value. It doesn’t matter which thermocouple I have it set for.

Reminder. There are a few good forum threads on this 16 bit out of range number and a few different ways to work with it.


Thank you guys for your quick support.
It was really helpful for me.