Correction error of master thermometer

Hi,

We are doing in house calibration of mercury in glass thermometer against the master thermometer, and we need to determine the correction error limit of the master thermometer.

 

Kindly share if have any experience on how to determine of correction error of master thermometer base on correction and uncertainty of master thermometer calibration result. 

 

Kind regards,

 

Indry 

 

 

 

There should be no variance in the master thermometer.  With regard to the thermometers you are calibrating to the master MIG then 1/2 degree variance is acceptable.

Hi,

We are doing in house calibration of mercury in glass thermometer against the master thermometer, and we need to determine the correction error limit of the master thermometer.

 

Kindly share if have any experience on how to determine of correction error of master thermometer base on correction and uncertainty of master thermometer calibration result. 

 

Kind regards,

 

Indry 

 

Hi Indry,

 

You will probably need to have the master thermometer externally, officially, traceably, calibrated.

The master thermometer has been calibrated by external laboratory. Which is the result of calibration shown the correction and uncertainty as I mention previously.

The master thermometer has been calibrated by external laboratory. Which is the result of calibration shown the correction and uncertainty as I mention previously.

 

Hi Indry,

 

Then I'm sorry but i don't quite understand what yr actual question was in the OP.

 

Normally the calibration report should include data on "correction errors" and "uncertainty" as determined by a stated Procedure.

 

Are you asking how to understand such data ? If so, can you upload a copy of the actual report or the relevant text/data since different Services vary in their presentation ?

Hi Charles,

 

Attached the results of thermometer calibration report. Sorry the result in Bahasa Indonesia version. The correction from +0.6 to 1.8 degree, with uncertainty 0.6 (+/- deg C). Which is our tolerance is 0.5 deg C. In your experience is that still acceptable?

 

Am just confused how supposed I do when we conduct the internal calibration for the MIGT's against the reference sample.

 

 

Hi Indry,

 

Thanks the attachment. I think I understand most of it. I deduce 2^nd column is your MIG, 3^rd column is external lab instrument.

 

If yr tolerance of +/-0.5 degC applies to the accuracy of the indicated MIG temperature in the range shown on the certificate, the MIG looks to be out of tolerance since the errors vary from 0.6 to 1.8 degC.

I have typically seen tolerances used from +/- (0.5 – 1.0) degC but the actual choice may depend on the specific use of the MIG and sometimes even Regulatory requirements.

 

Internal checks are usually limited to testing at 0 and 100degC as you no doubt know. IMEX the results are always a bit different to an external lab since the latter should have a more controlled environment and standardised testing conditions (in theory anyway).

 

My experience is mainly with thermocouples where you can adjust the zero to electronically correct for the error at a specific temperature and at the same time reduce the errors at other temperatures. Is it possible to adjust the scale on the MIG at all?

 

I suggest you have a look at thread below which has some similarities to yr query although oriented to BRC Standard. In particular see the document linked in Post 5 which explains the Certificate data quite well IMO.

 

http://www.ifsqn.com...ence-equipment/