Noise detection and avoidance

摘要

A process variable transmitter includes a sensor drive controller that outputs a sensor drive signal that is used to drive a sensor that senses a process variable. The sensor drive controller changes the frequency of the sensor drive signal to avoid frequencies and associated harmonics at which noise occurs and which could interfere with the sensor signal.

主权项

1. A method of using a process variable transmitter to control a process variable sensor that senses a process variable in a running process, the method comprising:
applying a sensor control signal to the process variable sensor; receiving a sensor signal from the process variable sensor related to the process variable, the sensor control signal, and noise in the process; retrieving frequency characteristics of the sensor control signal from a memory, the frequency characteristics of the sensor indicative of a primary drive frequency and harmonics of the sensor control signal; detecting noise in the sensor signal based upon the retrieved frequency characteristics; adjusting a sensor control signal frequency of the sensor control signal to reduce an effect of the noise in the process; and controlling the process variable sensor at the adjusted sensor control signal frequency.