Control Using Wireless Devices – Control Performance Part 2

The reliability of WirelessHART device communication has been well established. Even so, in the event of loss communication, the expected control behavior is of interest. The simulation environment was used to compare the behavior of the PIDPlus for loss of communications to a PID with a wired transmitter where the measurement value is frozen for a period of time. The response observed when the measurement was lost during a setpoint change is shown below.

The response observed when the measurement is lost after a process disturbance is shown below.

The Conventional PID provides poor dynamic response when the measurement is lost. As illustrated by these tests, the PIDPlus provides improved dynamic response under these conditions