Configure DAQMX thermocouple

[denisimb]

Hi,

I have Labview 7.1
First of all I have configure my CJC in the voltage mode and set the terminal configuration to RSE Mode.
After that, I configure my Type K Thermocouple. But I cannot put into the RSE mode, I don't have access to modify the mode!
What I have to do, If I want to use the RSE mode with DAQMX for a Thermocouple?

Thx and have a nice day!

[denisimb]

Sorry the card I use is a PCI-MIO-16E-4

[Sean_C.]

HEllo Denisimb,

Thank you for contacting National Instruments.

Thermocouple tasks default to differential mode. To measure a thermocouple in RSE, you will have to set up a voltage input task and apply the appripriate scale to map from Volts to Degrees.

I hope this helps.

Sean C.
Applications Engineer
National Instruments

[arogers]

I have an Omega K-Type Thermocouple that I am using for temperature measurements. Currently when I have it testing in MAX, I get an erroneous reading (i.e. 93 oC), and on top of that, when I swtich the option to Farenheit reading, the conversion is erroneous. At first I thought it was the thermocouple itself, but that was resolved when I got a good reading using a hand-held thermocouple reader. The card I'm using that is giving me errors (wrong temperature readings and inconsistent temperature conversions from F to Celsius) is a PCI-6035E card running NI-DAQ 7.4. I am also using a TC02 module in a SC-2345 Signal Conditioner. When I unplugged the SC-2345 and plugged in on another computer running NI-DAQ 7.3, the thermocouple operated fine. That machine uses a PCI-6221 card running NI-DAQ 7.3. This makes me think the error is in the PCI-6035E card. What are anybody's thoughts? Attached are some screen shots.

[Sean_C.]

Hello,

A quick check would be to install the 6035E in the computer running NI-DAQ 7.3. If it still gives bad readings, then it is deffinitely the card. If it reads correctly, then you might want to downgrade the original machine to 7.3 and see if that solves the problem.

Let me know your results.

Sean C.

[AIELLO Gianni]

Hello,

I have some problems with a K thermocouple. I use DAQmx 7.3.1, LabView 7.0 and a SCC2345 external module with TC02 amplificator. The signal changes between -25°C to 150°C at ambient temperature. I think I have rightly configurated the devices and the software and I don't find the error(s).

I have already tried to make aquisition with our models of vi and I have always the same strange signal.

More informations:
- NI DAQmx 6229 with CBL-068
- SCC-2345 with TC-02 thermocouple module
- 4 thermocouple K mounted in parallel mode (certified work properly)
- LabView 7.0 with NI DAQ drivers 7.3.1 (downloaded and installed today)

Best regards

[Sean_C.]

Hello Aiello,

How are you acquiring these signals? Are you using the DAQ Assistant, or the DAQmx VIs? What do you mean when you say you always have the "same strange signal"? Can you read the signals correctly from within Measurement and Automation Explorer (MAX)? Try running a test panel on your thermocouples.

You might want to install the latest version of NI-DAQ, 7.4 from: http://digital.ni.com/softlib.nsf/websearch/90B60D5899BCCCDB86256FC700581B89?opendocument&node=132060_US .

Please reply back with more information, and I will be glad to help you out.

Regards,
Sean C.

[AIELLO Gianni]

Hello Sean,

I'm acquiring these signal using DAQ Assistant and DAQmx VIs. The signal is like a sinusoidal courve and changes between -50 and +150°C. I have the same signal under LabView using VIs from NI.com database and using MAX too. The test window show me that the signal isn't constant. I repeat: my thermocouple is working right (I've checked it with an external device and I measure a constant temperature of 20°C in my lab...).

I will install DAQ drivers 7.4 and try again.

Thanks for your help

AIELLO Gianni

[Sean_C.]

Hello Aiello,

What measurement mode are you measuring this thermocouple with? You should be using RSE (referenced single ended).
Do you have any other SC-TC-02 modules to test this against? Try putting the SC-TC-02 in a different slot in the SCC-2345.

Let me know the results of these steps and the installation of NI-DAQ 7.4.

Regards,
Sean C.

[AIELLO Gianni]

Hello Sean,

I've installed the NIDAQ 7.4 without problems and now I can measure a correct value of thermocouple output voltage. The MAX needs a TEDS in order to enable the temperature conversion between the voltage and the temperature, but I don't find where download the TEDS. Can you help me?

I have only 1 SC-TC-02, I will try this morning to connect the device to another slot of the SC-2345 and make others measurements. I reply the results later.

Best regards

AIELLO Gianni

PS: I use RSE measurement mode.