Mitsubishi Electric MELSEC iQ-R Series - Page 1143

9 PID OPERATION INSTRUCTION
9.1 Overview
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Derivative time (T
D
): (s3)+6
Setting range: 0 to 32767 [ 10ms] (0 = no derivation)
PID control: Derivative action
The derivative time is used to be sensitive to the change in the process value (PV) caused by a disturbance and minimize the
changes.
• Increasing the derivative time (T
D
) prevents more positively the control target from fluctuating due to a disturbance.
Alarm output flag: (s3)+24
When the set input/output variation is exceeded, bits of (s3)+24 turn on as an alarm flag immediately after execution of the
PID operation instruction.
• When the input variation alarm (bit 1 of (s3)+1) is on
Derivative time (T
D
): T
D3
> T
D2
> T
D1
EV: Deviation
MV: Manipulated value
t: Time
PV: Process value
T
S
: Sampling time
t: Time
Bit 0 and bit 1 of (s3)+24: Alarm flag
T
D3
T
D1
T
D2
T
D3
T
D1
T
D2
EV
t
t
MV
EV
Disturbance
ON
ON
PV
t
T
S
Rate of change
(s3)+24 bit0
(s3)+24 bit1