Fluke 2176A thermocouple thermometer

[v6samurai86]

Hello. I have a Fluke 2176A thermometer that is calibrated to type T thermocouples. I have K thermocouples. The unit is supposedly also good with K thermocouples, but I do not see how to let it know there are K thermocouples attached. Does anyone know about this thermometer? I thought I'd ask before tearing the thing apart to try to tell. It seems if I put a thermocouple different than a T-type, I will get an inaccurate reading. Right?

Thanks!

 

[ione]

The thermometer can be coupled both to type T and to type K thermocouples. I do not think you need to select the type of thermocouple, just use the same type of thermocouple for all channels available.
The discrepancies you’ve detected when turning from T-type to K-type are in the nature of the thermocouple itself. Thermocouples type K and T have a different range of applicability. For type K (-210 °C to 1370 °C) while for type T (-210 °C to 400 °C). Their accuracy is different as well. The reference standard is IEC 584-2. If you have not access to this standard take a glance at the link below

http://www.microlink.co.uk/tctable.html

 

[IRstuff]

Depends on what temperatures you try to measure. At 150°C, a type K would read about about 12°C lower than a type T. You can use a number of online calculators to experiment:

http://www.hartscientific.com/funstuff/tc_its90_calc.htm

At 350°C, the reading error would be about 96°C

Closer to room temperature, the differences are less than the inherent uncertainties in the measurement itself.

TTFN

FAQ731-376

 

[v6samurai86]

OK, I did a bit of searching myself. The 2176A is internally set on a circuit card and it is not easy to change thermocouple types, it appears. It definitely DOES make a difference on the type of thermocouple used since each type will supply a different voltage and if the machine thinks it is a T thermocouple, the temperature reading will reflect that.

This is my plan: use the K-type thermocouples with the T-type thermometer. The reading will be a temperature resulting from a supplied voltage due to the temperature the thermocouple "sees". Using the cool converter supplied by IRstuff or charts that can be found online, like here:

http://www.omega.com/temperature/Z/zsection.asp

(See thermocouple reference data section)I can convert the read temperature to a voltage on the T-chart. I then go to the K-chart and use the voltage to find what the real temperature is.

Let me know if you guys think I'm crazy and I'm missing something!

Thanks!

 

[IRstuff]

Seems like a lot of work to do if you're going to be doing it more than once. Given that the meters are less than $200:

http://www.omega.com/ppt/pptsc.asp?ref=HHM290&ttID=HHM290&Nav=

you'll break even if you ever spend more than a couple of hours doing this.

TTFN

FAQ731-376

 

[ione]

You could prepare a spreadsheet using the polynomial formulation and the coefficients reported at page Z-26 of the attached paper, in order to compute temperature when knowing the voltage.