standard calibration tolerance

[Danfossegypt]

Dear Gents

I need to know if there is any standard for accepted calibration tolerance for PT, Thermocouples,RTD,....

Best Regards

 

[itsmoked]

Not really...
There are tolerances for devices like a 1% TC or 3% extension wire, but each user needs to define the accuracy and tolerance their particular case warrants. More accuracy = more money. You should figure out your requirements and go from there.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[IRstuff]

Your question does not quite compute. Which calibration accuracy are you refering to? The actual sensor uncertainty? or the calibrator uncertainty?

Your sensor uncertainty should be whatever is the specification for it.

Your calibrator uncertainty, traditionally, per MIL-HBK-52 is 1/10th the sensor uncertainty. However, it is generally accepted that a 4:1 test accuracy ratio is adequate.

TTFN

FAQ731-376

 

[Danfossegypt]

I mean if i am calibrating a transmitter by a certified calibrator, when i can accept this transmitter and when it is not accepted and i will need to replace the transmitter sensor module

 

[IRstuff]

Sorry, still not making sense. Is this "certified calibrator" a person or an instrument? If the former, then they should know what to do with your transmitter.

If the latter, what is your specification? Is it in spec or not? If not, is there a means of correcting the readings to be more correct? If not, then, yes, you have to deal with an instrument that doesn't meet specification?

[red]If you don't know what the specification is, then ASK the manufacturer.[/red]

TTFN

FAQ731-376

 

[JLSeagull]

What context?

Consider accuracy and precision to be commercial or contractual requirements. Does the contract include an accuracy requirement? Does the manufacturer make an accuracy claim? Assure that the latter is better than the former. Test to comply with the contractual requirements. Verify that the test instruments have a current calibration traceable to the NIS or such organization. Again the contract may define "current".

Six months test instrument calibration and about 0.5% accuracy may be about a good as you could expect for construction checkout of field instruments. Expect less for very low dp and for thermocouple temperature.