THERMAL-BASED DIAGNOSTIC SYSTEM FOR PROCESS TRANSMITTER

摘要

A process transmitter for measuring a process variable in an industrial process comprises a sensor module, a heating device and transmitter circuitry. The sensor module has a sensor for sensing a process variable of an industrial process and generating a sensor signal. The heating device is connected to the sensor module for generating a heat pulse to influence generation of the sensor signal. The transmitter circuitry is connected to the sensor and the heating device. The transmitter circuitry verifies operation of the sensor by measuring a change in the sensor signal due to the heat pulse. In one embodiment of the invention, the heat pulse thermally expands a volume of a fill fluid within the process transmitter. In another embodiment, the heat pulse changes a physical property, such as dielectric, of a fill fluid within the process transmitter.