FujiFilm FRENIC5000G11S Series, Technical Information

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Chapter 2
3. Function Explanation
■
H22 PID control (P-gain)
■
H23 PID control (I-gain)
■
H24 PID control (D-gain)
These functions are not generally used alone but are com-
bined like P control, PI control, PD control, and PID control.
• P operation
Operation using an operation amount (output frequency)
proportional to deviation is called P operation, which outputs
an operation amount proportional to deviation, though it
cannot eliminate deviation alone.
- Setting range: 0.01 to 10.0 times
P gain is the parameter that determines the response level for
the deviation of P operation. Although an increase in gain
speeds up response, an excessive gain causes vibration, and
a decrease in gain delays response.
• I operation
An operation where the change speed of the operation
amount (output frequency) is proportional to the deviation is
called I operation. I operation outputs an operation amount as
the integral of deviation and, therefore, has the effect of
matching the control amount (feedback amount) to the
reference value (e.g., set frequency), though it deteriorates
response for significant changes in deviation.
- Setting range: 0.0 (inactive), 0.1 to 9999s
Deviation
Operation
amount
Time
H22 P-GAIN
Response
Time
Deviation
Operation
amount
Time
“I: integration time” is used as a parameter to determine the
effect of I operation. A longer integration time delays response
and weakens resistance to external elements. A shorter
integration time speeds up response, but an integration time
that is too short causes vibration.
• D operation
An operation where the operation amount (output frequency)
is proportional to the deviation differential is called D opera-
tion, which outputs an operation amount as the deviation
differential and, therefore, is capable of responding to sudden
changes.
- Setting range: 0.00 (Inactive)
0.01 to 10.0s
“D: differential time” is used as a parameter to determine the
effect of a D operation. A longer differential time quickly
attenuates vibration caused by P operation at the occurrence
of deviation. Excessive differential time could cause vibration.
Shortening the differential time reduces attenuation at the
occurrence of deviation.
• PI control
P operation alone does not remove deviation completely. P
+ I control (where I operation is added to P operation) is
normally used to remove the remaining deviation. PI control
always operates to eliminate deviation even when the
reference value is changed or there is a constant distur-
bance. When I operation is strengthened, however, the
response for rapidly changing deviation deteriorates. P
operation can also be used individually for loads containing
an integral element.
• PD contro l
If deviation occurs under PD control, an operation amount
larger than that of D operation alone occurs rapidly and
prevents deviation from expanding. For a small deviation, P
operation is restricted. When the load contains an integral
element, P operation alone may allow responses to vibrate
due to the effect of the integral element, in which case PD
control is used to attenuate the vibration of P operation and
stabilize responses. In other words, this control is applied to
loads in processes without a braking function.
H23 I-GAIN
Time
Deviation
Operation
amount
H24 D-GAIN
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