This case concerned a pressure control problem in a burner. The plant operators noticed that the heat varied due to the pressure variations.

T The PID Tuner was used to find good PID settings. For that, a step experiment had to be done in a safe way. To ensure safety, we applied the option of a 'PVmax'. That was in this case the maximum pressure above which the step experiment would be stopped and control would resume.

"After the step experiments, new PID settings were calculated and applied immidiately. It appeared that the PID controller was tuned much better: pressure converged to setpoint five times faster!”

 

Software and hardware

De PID controller was programmed in an Allen Bradley PLC. The PID Tuner software communicated with the PLC via de OPC server of Rockwell Automation (RSLinx Classic OEM).

Results

The figure below shows the results of both old PID settings and new ones.


The PID Tuner was set up to execute its tuning in a safe way

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