My smart dp level transmitter is calibrated at 0-100" WC (bench calibrated). At the field tank's range is 20"WC to 50"WC (Zero Suppressed). Do I need to recalibrated if change the range to 20"WC to 50"WC?
Calibration is comparing the instrument's reading to a reading when a pressure standard is applied.
Whether a late model smart pressure transmitter needs calibration when changing the range is up to corporate policy. Having talked with others about what their policies are, those that require re-calibration are based on the criticality of the application and whether the range change stays within the same 'accuracy' band. Re-ranging 0-400" to 0-5" would be an example of not being the same accuracy band.
So, what's your corporate policy say?