Title: Can I calibrate the 418X with the PRT hole?
Applies To: 4180 and 4181
Problem Description: Why is there a PRT hole and what is it used for?
The 418x cannot be verified or calibrated by using the 1/8” 5608 12” probe hole at the top. The hole is used to see the difference in temperature from the IR Block to the reading of the KT19 thermal imager. This information is used by the Director of Metrology and Engineering for troubleshooting purposes only. The reading from the probe is not reported on the certificate because it is not valid and it should not be the same as the calibrated display temperature. The target must be calibrated and verified by using a radiometric thermometer. We use a Heitronics KT19 to calibrate/verify the radiant heat from the block and not the internal block temperature.
If for some reason you were to use the probe hole, you would see a large difference in temperature from the internal block to the IR gun.