Measuring temperature with NI9215 and TC type K

[CrownLouis]

Hello everyone,

I'm trying to measure the temperature directly from a thermocouple (TC) type K with a NI9215 card but I'm having complications because the value of temperature is jumping around in huge increments. I've been reading in some post from the forum that maybe is because of the range of the card and it doesn't detect the voltage from the TC, in my case 16 bits +- 10V, is that true? I also have another card NI PCIE-6323 but I think I wont be able to measure temperature neither.

The TC is well plugged and grounded.

I look forward for your answers

Thanks Luis

[Sibylle]

Hello Luis, 

This card has a max voltage range of +/- 10V with 16 bits resolution. The other device (PCIE-6323) is not a meant to measure a temperature with a thermocouple. 

I think you may have a problem on your application : have you done some test with NI MAX ? 

It's possible for you to send the code ?

Best regards, 

Sibylle 

[CrownLouis]

Hello Sibylle,

Yes, I have already tested with NI MAX, it was my first test. The temperature measure value should be 30° C but instead, it shows an erratic curve of values, judge by yourself.

I tryed also the VI example from Labview (Analog Input - Voltage and Thermocouple in a single Task.vi) and it gives exactly the same, a erratic curve of values.

As I said beafore, the thermocouple is well plugged and grounded.

I look forward for your answer

Luis

[Sibylle]

Hi Luis,

I see your screenshot, have you tested to put " Source de CSF" at "intégré" ?

You can see on the page 14-15 of this document (http://www.ni.com/pdf/manuals/373779g.pdf) the correct wiring, please check it. 

Best regards, 

Sibylle 

[CrownLouis]

Hello Sibylle,

I already tried to put "Integer" but NI sends an error.

[Sibylle]

Hello Luis, 

I tried to use the same material with a TC and I have some questions : 

1. Do you have an other card and chassis to see if the porblem is the same?
2. Wich type of chassis do you use ?
3. Do you have the same problem on any other channel ? 
4. Have you correctly plugged a 1 Mohms resistor between AI0- and COM
5. It is possible for you to change the cable between your computer and your card ? Just to be sure it is not he communication toward the PC that is faulty
6. It is possible for you to test an other TC and to test this TC with an other device ? 

Best regards, 

Sibylle