Mitsubishi Electric MELSEC iQ-F FX5 - Page 634

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35 CPU MODULE BUILT-IN ANALOG FUNCTION
35.5 Function (PID Control Via Instruction)
Reduction of remaining deviation
When reducing the remaining deviation, the operation is as follows.
• Remaining deviation according to the input value
When the control result is stable around the target value and the required output value is small, the control result may not
converge to the target value because of the influence of noise. In that case, increase the input filter constant ((s3)+2) to
suppress the influence of noise. The control result may converge to the target value.
Control result when the input filter is not used Control result when the input filter constant is increased
(1) Deviation remains and the input value does not converge to the target
value.
(2) Excessive output is generated in response to indirect changes.
(1) The input value converges to the target value.
(2) Excessive output is suppressed.
Time
Target value
(1)
Time
(2)
Input value
(PV)
Output value
(MV)
Time
Target value
(1)
Time
(2)
Input value
(PV)
Output value
(MV)