NONLINEARITY TESTING OF EQUIPMENT USED IN TEMPERATURE MEASUREMENTS |
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| Tadej Podgornik, Valentin Batagelj, Jovan Bojkovski, Janko Drnovšek |
- Abstract:
- In this paper the nonlinearity testing of seven resistance instruments used to measure temperature is presented. Tested were four multi-meter type instruments which use the UI method to determine resistance and three resistance bridges that measure resistance as a ratio between a resistance thermometer and a standard resistor.
The device used to measure the nonlinearity of the instruments was a RBC100 resistance bridge calibrator. The device is a passive four resistor matrix that enables for 35 different resistances to be generated by parallel/series switching of the four base resistors. The device had been previously automated for easier use. This eliminates the need for an operator to be present during calibration, the device can also be placed in an thermally stable enclosure and switched from within it. The software that was purposely developed for the automated work with the RBC100 controls both the calibrator as well as gathers measurements from the instrument under test. The software also calculates non-linearity and keeps record of the measurements that were performed.
During testing, two rounds of measurement sets were performed. During each round 3 sets of all 35 combinations were measured on every instrument under test. The multi-meter type instruments nonlinearity was measured to be far lower than the declared uncertainty. The linearities of the resistance bridges were in most cases equal to the declared uncertainty value. This was however to be expected, since bridge nonlinearity accounts for the major part of its uncertainty. Non-linearities were in the range from 380 µΩ (6 ½ digit multi-meter) down to 2 µΩ (best resistance bridge). - Keywords:
- resistance bridge, SPRT, non-linearity
- Download:
- IMEKO-WC-2009-TC4-399.pdf
- DOI:
- -
- Event details
- Event name:
- XIX IMEKO World Congress
- Title:
Fundamental and Applied Metrology
- Place:
- Lisbon, PORTUGAL
- Time:
- 06 September 2009 - 11 September 2009