Process Measurement and Control, Faculty of Chemical Engineering and Technology, University of Zagreb

TITLETITLEName and surnameName and surname

Process Measurement and Control, Faculty of Chemical Engineering and Technology, University of Zagreb

CONTENTCONTENT

• Control loop dynamics

• Basic principle of controller tuningBasic principle of controller tuning

• Controller parameter optimisation

• Tips for controller optimal tuning

Process Measurement and Control, Faculty of Chemical Engineering and Technology, University of Zagreb

TYPES OF PID CONTROL TYPES OF PID CONTROL ALGORITHMSALGORITHMS

1)1) SERIAL algorithmSERIAL algorithm ((real, interactive, analogreal, interactive, analog))

• It has been used by analogue (pneumatic) controllers;• Very tedious for tuning.

2)2) PARALLEL algorithmPARALLEL algorithm

• It has been used within electronic equipment until the appearance of microprocessor;• Simplier for tuning.

3)3) IDEAL algorithmIDEAL algorithm ((noninteractive, digitalnoninteractive, digital))

• The algorithm developed with appearing of digital computers; • The most widely used algorithm.

Process Measurement and Control, Faculty of Chemical Engineering and Technology, University of Zagreb

• Minimum settling time of a control loop is between sluggish and oscillating process response;

• Minimum settling time depends on the control loop dead time, and to some extent on the time constant:

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Process dynamics Minimal settling time

2

3

4

Integrating process 4

12min,stMinimal settling time:

Process Measurement and Control, Faculty of Chemical Engineering and Technology, University of Zagreb

• Usually only used for simple loops, with no necessity to exactly match set point.

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Influence of the controller gain changes in P-only controller on the process response

Time (min)

KC increases

Manual modeKC = 0

PV