Salicru CV50-008-4F User Manual page 94

7.10.1 General steps of PID parameters setting:
a) Ensure the gain P
When ensure the gain P, firstly cancel the PID integration and derivation values (set Ti=0 and Td=0, see the
PID parameter setting for detailed information) to make proportional adjustment the only method to vary PID
control. Set the input as 60%~70% of the permitted Max. Value and increase gain P from 0 until the system
vibration occurs. Now do it vice versa. Then record the P value and set it to 60%~70% of the current value.
After that, the gain P commission is finished.
b) Ensure the integration time
After ensuring the gain P, set an original value of a bigger integration time and decrease it until the system
vibration occurs. Then do it vice versa, until the system vibration disappear. Record the Ti and set the
integration time to 150%~180% of the current value. Then integration time commission is finished.
c) Ensure the derivation time
Generally, it is not necessary to set Td. Usually, the value is 0.
If it needs to be set, set it to 30% of the value without vibration via the same method than with P and Ti.
d) Commission the system with and without load, and then adjust the PID parameters until it is available.
7.10.2 PID inching
After setting the PID control parameters, inching is possible by following means:
Control the overshoot
Shorten the derivation time and prolong the integration time when overshoot occurs.
Achieve the stable state as soon as possible
Shorten the integration time (Ti) and prolong the derivation time (Td) even the overshoot occurs, but the
control should be stable as soon as possible.
Control long vibration
If the vibration periods are longer than the set value of integration time (Ti), it is necessary to prolong the
integration time (Ti) to control the vibration for the strong integration.
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