Toshiba TOSVERT VF-nC3 Instruction Manual page 138

4) Adjusting the PID control gain level
Adjust the PID control gain level according to the process quantities, the feedback signals and the object to
be controlled.
The following parameters are provided for gain adjustment:
 (P-gain adjustment parameter)
6
 (I-gain adjustment parameter)
Title Function

Proportional gain (P)

Integral gain (I)

Derivative gain (D)
This parameter adjusts the proportional gain level during PID control. A correction value proportional to
the particular deviation (the difference between the process quantity and the feedback value) is
obtained by multiplying this deviation by the parameter setting.
A larger P-gain adjustment value gives faster response. Too large an adjustment value, however,
results in an unstable event such as hunting.
Feedback amount
Fast response
(  = Large gain)
This parameter adjusts the integral gain level during PID control. Any deviations remaining unremoved
during proportional action are cleared to zero (residual deviation offset function).
A larger I-gain adjustment value reduces residual deviations. Too large an adjustment value, however,
results in an unstable event such as hunting.
Feedback amount
Assign an input terminal function 52 (PID integral/derivative) to an input terminal, when that input
terminal is ON, it is possible to calculate integral/derivative amounts always as 0 (zero).
Adjustment range Standard defaults
0.01 ∼ 100.0
0.01 ∼ 100.0
0.00 ∼ 2.55
Slow response (  = Small gain)
( = Small gain)
Residual deviation
( = Large gain)
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0.30
0.20
0.00
Process quantity
Time
Process quantity
Time