Direct/Reverse Action Selection Function; Rfb Limiter Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

1.13

Direct/reverse Action Selection Function

Whether to execute a PID operation with a direct action or a reverse action can be selected.
This function can be used in all the control methods (two-position control, P control, PI control, PD control, and PID control).
( Page 18 Control Method)
For details on the operation, refer to the following:
Page 336 Actions of the temperature control module
Setting method
Configure the setting as follows:
[Navigation window]  [Parameter]  Target module  [Application Setting] [Normal Operation/Reverse Operation
Setting]
1.14

RFB Limiter Function

The RFB (reset feedback) function operates when deviation (E) continues for a long period of time.
When the deviation (E) continues for a long period of time, this function prevents the PID operation results (manipulated value
(MV)) calculated by integral actions from exceeding the effective range of the manipulated value (MV).
This function automatically operates when the PID control is executed. No setting is required.
When a PID operation result is larger than the upper limit output limiter value, the temperature control module
operates as follows:
• The RFB function levels the manipulated value (MV) to the upper limit output limiter value by feeding back
an excess value to the integral value.
When a PID operation result is smaller than the lower limit output limiter value, the temperature control
module operates as follows:
• The RFB function levels the manipulated value (MV) to the lower limit output limiter value by feeding back a
required value to the integral value.
1 FUNCTIONS
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1.13 Direct/reverse Action Selection Function