AC70 VC CONTROL FREQUENCY INVERTER MANUAL
FUNCTION PARAMETER DETAILED SPECIFICATION
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H-19 Proportion gain P
Range: 0.1-100.0
Default: 20.0
H-20 Integral time constant I
Range: 0.1-100.0s
Default: 2.0s
H-21 Differential gain D
Range: 0.0-10.0
Default: 0.0
Adjusting parameters in PID control function, these parameters should be set according to actual system
characteristic in respectively.
Proportion gain P:
This parameter determines the impact degree of Proportion gain P respond to deviations.
When gain is large, it responds quickly, but would bring out oscillation. When gain is small, respond will delay.
Integral time constant I:
It decides the size of respond effect for Integral time I. When the integral time is big, the
respond is slow, In addition, anti-external interference is become weaker. If the integral time is small, the respond
speed is quick. But oscillation would occur if it is set too small.
Differential gain D:
When the deviation of PID feedback value and PID given value changes, The output and the
change rate of deviation are proportionally adjusted. This adjustment is only related to the direction and size of the
deviation change and has nothing to do with the direction and size of the deviation itself. While the feedback signal
changes, differential adjustment is used to adjust according the change trend to restrain the change of feedback
signal. Please be careful to use the differential adjustment. Because it will amply the system interference, especially
for a higher changing frequency interference.
H-22 Sampling period
Range: 0.01-60.00s
Default: 0.10s
This parameter is only valid for the sampling period of feedback value. The regulator will calculates a time in every
sampling period. The small sampling period, the quicker respond time.
H-23 PID control deviation limit
Range: 0.0%-20.0%
Default: 0.0%
The maximum deviation allows for PID feedback value to PID given value. PID will be stop, keep output constant
when the feedback value within this deviation range. It will coordinate the contradiction between the accuracy of
system output and stability with using this function properly.
H-24 Starting threshold value
Range:0.0%-Sleep threshold value
Default:0.0%
H-25 Sleep threshold value
Range: Starting threshold value-100.0%
Default:100.0%
Starting threshold value:
When inverter goes into sleep mode, inverter restarts should require PID feedback value
less than starting threshold value setting. If the the starting threshold value is set too high, inverter will start and
stop frequently. If it set too low, it will cause pressure not enough. This parameter is defined as percentage of PID
feedback value to sensor maximum measuring range account for.