Version 1.0 09/08/2017
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71
Code
Parameter name
Setting range
Factory default
Change
Proportional gain (KP) : used to decide the extent of the PID regulator,the greater P,the greater adjusting extent. This parameter 100
means that when the deviation of PID feedback value and setting value is 100%, the PID regulator will adjust the output frequency
command to the maximum output frequency (Ignore the integral and differential actions) .
Integration time (Ti) : used to decide the speed that PID regulator adjusts integrally the deviation between feedbacks and settings of
PID. The integration time means that when the deviation of PID feedback value and setting value is 100%, the integration regulator (Ignore
proportional and derivative actions) will successively adjust to the maximum output frequency (F0.08) for the time. The shorter integration
time, the greater extent of integral adjustment
Differential time (Td) : used to decide the extent that PID regulator adjusts the deviation between feedbacks and settings of PID. The
differential time means that the feedback value changes 100% within the time, the differential regulator will adjust to the maximum
output frequency (F0.08) (Ignore proportional and integral action) . The longer differential time, the greater extent of adjustment
PID is the most commonly used control method in the process control, and the role of its each part varies, the working principle and
the adjusting method is briefly described as follows:
Proportional adjustment (P) : When the deviation between feedback and setting exists, as for the adjustment amount that the output
is proportional to the deviation, if the deviation is constant, then the adjustment amount will be constant too. Proportional adjustment
can respond quickly to changes in the feedback, but simply adopt proportional adjustment, which can not realize the control without
difference. The larger proportional gain, the faster the system adjustment, but if the too large proportional gain will cause oscillation. How
to adjust: firstly set integration time to very long, and set differential time to zero, simply adopt proportional adjustment to make the
system running, then change the setting value to observe the deviation (static difference) between feedback signal and setting amount, if
the static difference changes in the direction of setting amount (for example, when increasing setting amount, the feedback amount is
always less than setting amount after the system is stable), continue to increase the proportional gain, and vice versa reduce the
proportional gain, repeat the above process until the static difference is relatively small (it is hard to achieve zero static difference) .
Integration time (I) : when the deviation between feedback and setting exists, the output adjustment amount continuously increases,
if the deviation persists, the adjustment amounts will continue to increase until zero deviation. The integration regulator can effectively
eliminate static difference. If the action of integration regulator shows too strong, the overshoot occurs repeatedly, the system shows
unstable until oscillation. The oscillations caused by too strong integral action is characterized by that the feedback signal bobs and the
range of oscillation gradually increases until the oscillation. The integration time parameter adjustment generally descend, gradually adjust
the integration time to observe the effect of system adjustment until the system reaches the steady speed requirements.
Differential time (D) : when the deviation of feedback and setting changes, as for the adjustment amount that the output is
proportional to the deviation, the adjustment amount only have something to do with the direction and size of deviation change, not itself
direction and size. The role of differential regulation adjusts according to the changing trends when the feedback signal changes,thereby
suppressing the changes of feedback signal. Please use differential regulator with caution, because the differential easily amplify the
interference of system, especially the interference of high changes frequency.
E2.07
Sampling period (T)
0.01 to 100.00s
0.10s
☆
E2.08
PID control deviation limit
0.0 to 100.0%
0.0%
☆
Sampling period (T) : refers to the sampling period of feedback amount, the regulator operates once each sampling
period. The greater sampling period, the slower response.
PID control deviation limit: refers to allowable deviation between PID system output value and closed-loop setting
value, as shown in figure, PID regulator stops adjustment. The reasonable setting to this function code can adjust the
accuracy and stability of PID system.
The relationship between deviation limit and output frequency
E2.09
Feedback disconnection detection
value
0.0 to 100.0%
0.0%
☆
E2.10
Feedback disconnection detection
time
0.0 to 3600.0s
1.0 s
☆
Setting
s
Output
frequency
Feedback
amount
t
t
Deviation
limit