A STUDY OF THE IMPACT OF RTPW SHIFT ON SPRT AND PRT ACCURACY |
|---|
| Michael Coleman, Thomas J. Wiandt, Thomas G. Harper |
- Abstract:
- At Fluke’s Primary Temperature Calibration Laboratory, we recommend that our calibration customers monitor SPRT and PRT drift by tracking each thermometer’s resistance at the triple-point of water (RTPW). We also encourage our customers to update their temperature readout with the thermometer’s RTPW value measured by the same readout whenever it is possible. This is important since RTPW is used by the readout to calculate temperature. In response to these instructions, our customers often ask how much an SPRT or PRT should be allowed to drift at the triple-point of water (TPW) before it needs to be annealed or recalibrated. The answer to this question is complicated because it is difficult to know how much RTPW can change before WT90 changes. In order to answer this question, RTPWand WT90 drift data from a variety of SPRT and PRT models is presented to show how RTPWdrift affects accuracy over the entire range of calibration. Also, a concise description of the mathematics and process involved in ITS-90 temperature calculation is given to demonstrate the reason why RTPW is so important for measurement accuracy. The intent is to present data and information that allow the reader to determine appropriate RTPW drift guidelines for their measurement needs.
- Download:
- IMEKO-TC4-2011-036.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC4
- Event name:
- TC4 Symposium 2011
- Title:
XVIIIth IMEKO TC4 International Symposium on Measurement of Electrical Quantities (part of Metrologia2011, together with IX International Congress on Electrical Metrology - IX SEMETRO)
- Place:
- Natal, BRAZIL
- Time:
- 27 September 2011 - 30 September 2011