Simulating Thermocouples using SMUs

[vvsw]

Thermocouples essentially are very nonlinear voltage sources. They ouput known voltage values to different temperatures.

So I can characterize and potentially calibrate some thermocouple measuring devices I thought about linking the known tables to a signal generation:

http://www.ni.com/white-paper/4231/en/

Did anyone already developed such piece of code?

I think this is a very cool project to essentially create a virtual instrument that replaces a Fluke 714.

Very excited to see what the community already did.

[Matthew_Kelton]

You do realize that the table you linked to is in mV?  That means you would need a stable, repeatable power source that is accurate down to the 10 or 100 nanovolt range to stand a chance of being able to simulate a thermocouple voltage.  The code would be fairly straight forward, but the hardware is the issue here.

[vvsw]

You bring up a very good point.

This may require a configuration change and use a calibrator instead or some type of voltage divider.

As of the output calculations would you say we should use a lookup table with the values entered "by hand" or are you aware of a ready to use VI?

[Matthew_Kelton]

You can do the table lookup, but since it so so non-linear, your error will probably be pretty bad.

I would use the formulas:

https://www.omega.com/temperature/Z/pdf/z198-201.pdf

I don't know of any existing VI, but agin, it is pretty simple and straight forward to code up the formulas.

[nathand]

LabVIEW comes with a VI that implements thermocouple equations. Take a look at C:\Program Files (x86)\National Instruments\LabVIEW 2015\vi.lib\Utility\TradDaqScaling.llb\Temperature to Volts.vi (adjust for your version of LabVIEW). This VI is buried in the "Convert Thermocouple Reading" VI, found under the Mathematics -> Numeric -> Scaling palette.