9.1.1. Precautions

Before checking or starting any calibration procedure the following precautions should be taken:-

 

1. RTD and CJC calibration must not be carried out without prior mV calibration.

2. When calibrating mV inputs make sure that the calibrating source output is set to less than 250mV before connecting it to the mV terminals. If a large potential is accidentally applied (even for less than 1 second), then at least one hour should elapse before commencing the calibration.

3. A pre-wired jig built using a spare instrument sleeve may help to speed up the calibration procedure especially if a number of instruments are to be calibrated.

4. Power should be turned on only after the controller has been inserted in the sleeve of the pre-wired circuit. Power should also be turned off before removing the controller from its sleeve.

5. Ten minutes should be allowed for the controller to warm up after switch on.