SHENZHEN INVT ELECTRIC CO., LTD. CHV160 Operation Manual
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happens. Normally the integral time is adjusted from big to small, gradually regulate the
integral time, and watch the effect, until the system stable speed meets requirements.
Differential time (D): when the discrepancy between feedback and assignment varies,
output a regulation amount in proportion to the variance ratio of discrepancy. The regulation
amount is related to the direction and magnitude of discrepancy variation, but irrelevant to the
direction and value of the discrepancy itself. The differential control action is to perform the
control according to the varying trend when the feedback signal variation happens, and
thereby to restrain the feedback signal variation. It should be caution to use differential
controller as the differential control have a trend to magnify the system interference, especially
the high varying frequency interference.
Function
Code
Name
Description
Setting range
Default
Value
P9.07
Sampling time (T)
0.01
100.00s
0.01
100.00
0.50s
P9.08
PID control discrepancy limit
0.0
100.0%
0.0
100.0
0.0%
Sampling time (T): is the time to sample the feedback value. In each sampling period the
controller runs one time. The longer the sampling time, the slower the responding.
PID control discrepancy limit: the allowable maximum discrepancy of PID system output
value relative to the closed-loop assigned value. As shown in following diagram, within the
discrepancy limit, PID controller stops adjustment. Properly setting this function code can
improve the accuracy and stability of PID system.
Figure 6-21 Coincidence relation of discrepancy limit and output frequency
Function
Code
Name
Description
Setting
range
Default
Value
P9.09
PID output buffering time
0.00
10.00s
0.00
10.00
0.00
PID output buffering time: filter the analog input signal to prevent frequently jumping
interference signal producing impact on the system. But filtering time being too long can affect
