<Appendix 5. PID Block>
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A5.7 Control Action Bypass
The PID calculation processing can be bypassed so as to set the SP value as the operation
output (OUT).
The bypass setting is performed if the parameter BYPASS is set to “On”.
The block diagram is shown in the figure below.
Setpoint
Control
Feed-
forward
CAS_IN
Filter
IN
PV
BYPASS
SP
RCAS_IN
Output
OUT
FA0102.EPS
A5.8 Feed-forward
Feed-forward is a control action to add a compensation output value (FF_VAL) to the output
signal of the PID calculation.
This is typically used for feed-forward control.
The figure below illustrates the action.
PID
computation
FF_SCALE
OUT_SCALE
PV
OUT
FF_VAL
FF_GAIN
FA0103.EPS