A process transmitter for measuring a process variable in an industrial process comprises a gauge pressure sensor, an excitation source and transmitter circuitry. The gauge pressure sensor measures a pressure difference between a process fluid and a reference volume, and generates a pressure sensor signal representing the pressure difference. The excitation source generates a pressure pulse within the reference volume to influence generation of the pressure sensor signal. The transmitter circuitry is connected to the gauge pressure sensor to provide an output related to a change in the pressure sensor signal due to the pressure pulse.