Image Number 8 for United States Patent #6686831.
A process control instrument includes a sensor/actuator portion and a transmitter portion connected to the sensor/actuator portion. The transmitter portion is operable to communicate with other process variable transmitters through a communication network. The transmitter includes a processing module and a power module operable to generate a power output supplied to at least the transmitter portion, wherein the power module is operable to adjust the power output based on a power control signal. Moreover, the power control signal may be generated by a controller device remote from the process control instrument and communicated to the process control instrument over the communication network. Additionally, the power module includes a power control module for adjusting the power output. This power control module includes an amplitude limiter operable to limit a power input to the process control instrument according to a controllable amplitude limit, and a power rate of change unit operable to limit a rate of change of the power input to the process control instrument according to a controllable adjustment rate limit.