Is there an easy way to calibrate thermocouple connected to a 1102 module?

[Chris_D1]

I am trying to calibrate our thermocouple channels on the SCXI 1102 module. Is there a way to just plug a precision calibrator into the channel set to a temperature and have LabView take the reading and correct the calibration constants and then write them to the EEPROM? We haven't been able to find an easy way to do this.

[Gigot]

Chris,

Not familiar with the SCXI 1102 module but from reading about it on the NI
site its a straight forward TC AtoD board.

Since you have 32 channels to deal with there are offsets for each channel
that may need consideration.

What overall system uncertainties are you shooting for?

Yes you can buy a calibrator that produces mV/Degree outputs that correspond
to standards 385 is probably
what you'll be using. Calibrator's can look both ways that is they can
simulate a thermocouple or look at a thermocouple.
Knowing this you can look at TC specs and also generate mV's towards the
SCXI and verify both components of the system.

Keep in mind that you will have to rotate the calibrator to each channel and
then set the calibrator to a minimum of 3 points
i.e. LO MED HI.
This will provide calibration points across your range of
interrest, or a single point near your operating point.
The second method has the most uncertainties, but is probably OK for most
cases. Again its all driven by your unceratinty
needs. The more zeroes the more $$$

Good Luck



"Chris D" wrote in message
news:506500000008000000F5380000-1007855737000@exchange.ni.com...
> I am trying to calibrate our thermocouple channels on the SCXI 1102
> module. Is there a way to just plug a precision calibrator into the
> channel set to a temperature and have LabView take the reading and
> correct the calibration constants and then write them to the EEPROM?
> We haven't been able to find an easy way to do this.

[Chris_D1]

We already have a precision calibrator which we use to calibrate other data aquistion systems with. What I'm really wondering is if there is a VI or something that will take my simulated thermocouple temperature, do the necessary scaling, and save it the the module EEPROM.

[Filipe A.]

Chris;

As long as you have the calibrator which generates a temperature value, you are good to go. I'm attaching a Labview example VI which shows how to do calibration on the 1102 module.
Hope this helps.
Filipe

[Sargon]

I am having some problems calibrating my SCXI channels. I downloaded your calibration software but I still can't seem to get a good cal on a channel. Every time I calibrate I go to read the temp on the channel and it reads about 80000deg. I am using a micromite to calibrate the channel. I have it set to mV so that I know what I am putting into the system. I have tried using 10mv, 25mv, 50mv and all of them seem to do the same thing. My SCXI gain is 100. When it calculates the binary value for my signal it reads about 32000. When the screen pops up to show my the voltage it has an error. When I clear the error the voltage value is 1/2 the value I put in. I am hoping this is all just something I am doing incorrect with my input signals and how I setup
the channel. Any help would by appreciated.
Thank You
Philip

[ErikL68]

Do you have a current version of the 1102 cal example? It won't open in LabVIEW 8.6.

Thanks,
Erik

[ErikL68]

Just FYI - the reason I ask is for some reason, a cal routine we have for 1102 cards and TC-2095s attached to an E-series card through an SCXI-1001 chassis suddenly isn't saving Cal constants.  I suspect it may be NiDAQ 7.4.4 (we had no problems with LV 6.1 and NiDAQ 6.9.2) as that is the version I've started using in prep for a new release of our DAQ app being written in LV 8.6.

Erik

[BME_genuis]

I have a similar setup.  I would like to calibrate the thermocouple channel after simulating an accurate voltage using FLuke 714 in the channel on the terminal block.  Which VI do you use in the library of files?  How do you go about calibrating it?  Can you do it on LV 5.1.1 and DAQ driver 6.8.1 running Windows ME?  The subVI that I am using to convert voltage to thermocouple temperature is Convert Thermocouple Buffer.vi.