9.1.4 To Check RTD Input Calibration

Connect a decade box with a resolution to two decimal places in place of the RTD as indicated on the connection diagram below before the instrument is powered up. Make sure that the internal resistance of the box, the interconnection leads and any other connections are kept as low as possible – certainly less than 22ohms and preferably <1ohm. If at any instant the instrument was powered up without this connection then at least 10 minutes must elapse from the time of restoring this connection before RTD calibration check can take place.

 

 

The RTD range of the instrument is -200 to 850^OC. It is, however, unlikely that it will be necessary to check the instrument over this full range.

 

Set the resistance of the decade box to the minimum range. For example 0^OC = 100.00Ω. Check the calibration is within ±0.25% of reading ±1LSD.

 

Set the resistance of the decade box to the maximum range. For example 200^OC = 175.86Ω. Check the calibration is within ±0.25% of reading ±1LSD.