Thermocouple Calibrator

[talldude42]

I am looking for a relatively cheap thermocouple calibrator. Something we can plug the thermocouples on our machines into to verify their accuracy and if needed make changes on the controllers to offset any differences. I havent done this before.

Is one of these what I am looking for?
https://www.newark.com/fluke/fluke-714b-cal/thermocouple-calibrator-5-dig/dp/12AC7360?st=thermocouple%20%20calibration

Our test equipment is calibrated by an outsourced company. But I was told by one of our internal quality auditors that according to the IATF 16949 standard all of the thermocouples may need to be calibrated through out the shop but still looking into that

 

[TWS]

you should be using a dry block calibrator.
Here is a source: https://www.transcat.com/products/calibration-instruments/temperature-calibrators/dry-blocks.
You should pick a calibrator that matches the range of your thermocouples.

 

[NetNathan]

I am looking for a relatively cheap thermocouple calibrator. Something we can plug the thermocouples on our machines into to verify their accuracy and if needed make changes on the controllers to offset any differences. I haven't done this before.

Is one of these what I am looking for?
https://www.newark.com/fluke/fluke-714b-cal/thermocouple-calibrator-5-dig/dp/12AC7360?st=thermocouple%20%20calibration

Our test equipment is calibrated by an outsourced company. But I was told by one of our internal quality auditors that according to the IATF 16949 standard all of the thermocouples may need to be calibrated through out the shop but still looking into that

You only need dry block calibrator if you need to verify TC accuracy. It will be cheaper to get a certified TC and compare it to the existing TC when it is within 2" or less.
I believe you only need to verify instrumentation. Plus a dry block calibrator will not verify your instrumentation and lead wire.

Yes that Fluke will be fine..
However depending on the specifications your company uses... You may have to keep it calibrated also.
Are you doing aerospace work? Do you have to adhere to AMS2750?

 

[ndzied1]

For general setup work we use this:
http://www.extech-online.com/index....id=100&zenid=96217e6cd8e91b0cdf7af05e895cbb1b

Probably not what I'd use if we had to prove calibration etc. but very handy.

 

[Elcan]

I am looking for a relatively cheap thermocouple calibrator.

Water with ice.

 

[drbitboy]

Water with ice.

And put the ice into the water, not the other way 'round.

 

[AustralIan]

And, don't pressurize your ice/water mixture, or you could be off by up to 22°C or so.

 

[talldude42]

I have reached out to our thermocouple supplier Big Chief is the thermocouples are verified accurate or certified and what the ranges are ( we range from 300 to 500*F or 0 to -300 on our cryo equipment). But im assuming they are just rebranded thermocouples.

 

[talldude42]

You only need dry block calibrator if you need to verify TC accuracy. It will be cheaper to get a certified TC and compare it to the existing TC when it is within 2" or less.
I believe you only need to verify instrumentation. Plus a dry block calibrator will not verify your instrumentation and lead wire.

Yes that Fluke will be fine..
However depending on the specifications your company uses... You may have to keep it calibrated also.
Are you doing aerospace work? Do you have to adhere to AMS2750?

No we do not have to adhere to the AMS2750. But yes whatever device we would use, i would have that calibrated by an external source that calibrates the lab equipment since they are out once a year anyway.

 

[talldude42]

I guess Im not seeing the difference in verifying accuracy and "calibrating" the thermocouples/controller. I mean you cant actually calibrate the thermocouple itself right? You would find out the difference in what the thermocouple reads versus what the calibrator says it should read and program the controller to compensate for that difference?

 

[danw]

Using the best thermocouple calibrator in the world that reads out in temperature units does not mean anything unless you know what temperature the thermocouple's hot junction is at. That's what the dry block calibrator (or oil bath for lower temperatures) is for - a means of getting the sensor to a certain known and 'certified' temperature so that the T/C's output can be measured and compared by a certified calibrator to the temperature source's indicated temperature.

 

[NetNathan]

Order your thermocouples calibrated every 100 degrees (since you have a short range) from the low to the high range of your equipment. They will come with a calibration paperwork showing error.
If you use the same thermocouple for both types of equipment, get the calibration done at -300 to 500 degrees. If not, then order 1 set of TCs certified to -300 to 0 for the Cryo and the other set at 100 to 500 for the oven.
Make sure you specify "special Limits" wire top be used. This will tighten the accuracy of the wire.
Try a good TC house... Like GeoCorp or Cleveland labs.

You will still need a calibrator to verify lead wire and instrumentation accuracy.

 

[talldude42]

Ok. I got it now. Thank you very much for the information people! much appreciated.

 

[danw]

I concur with NetNathan's assessment, it's what I'd do if I were spending my company's money.


It is generally quicker and cheaper to get replacement thermocouples with certs than to do re-calibration.