Thermocouple Measurements on TBX-68T with PCI-4351

[nkey]

I have set up Traditional NIDAQ Virtual Channels for 2 different thermocouples. In a simple program, I wire each channel to AI Sample Channel.vi and get the temperature reading. This works fine. However, when I do this inside of a larger code where I am also reading voltage measurements on my PCI-4351 (using 435xFast.vi which I downloaded), the first thermocouple I read is always giving an erroneous error. Do I have to reset the board in some way before I take the temperature readings?

[LoganS]

What error are you getting? Does it have an error code? Please let me know, and have a great day!

Logan Sheen
National Instruments

[nkey]

I am not getting an error code, I am just getting very large value, negative readings from my thermocouple. The quickest work around was to simply ignore the first reading, and take the second reading, which is fine. However, I think I should try to understand what I need to do to reset the board to take a correct thermocouple measurement the first time. Any ideas?

[LoganS]

I've got just a few questions for you:

1. Are you seeing a large negative value anywhere else other than when you run your particular vi as a subvi? Test panels in MAX? Other example programs?
2. Do you have the latest drivers for your application? NI-DMM 2.3.1? NI-DAQ 7.3.1? NI-435x 1.1?
3. Have you tried reseting the board in MAX and then running your application? If this takes care of that first bad sample, you could try calling Reset Device in the Traditional DAQ function palette before starting your acquisition.

Please let me know what you can. Have a great Thanksgiving!

Logan S.