VAT 642 GP Series Installation, Operating, & Maintenance Instructions page 53

Series 642 INSTALLATION
2. Optimizing P gain
While optimizing P gain, the gas flow determined above has to be constant all the time.
Start optimization with P gain set to 1.0 and I gain set to 0.0.
Set chamber pressure to SP2, wait until the pressure is stable. Set pressure to SP1. If the transition from
SP2 to SP1 results in a significant pressure over shoot or even does not stabilize at all, the P gain is too
high. If there is no over shoot and the pressure reaches SP1 asymptotically and very slow, P gain is too
low.
The optimal P gain value is found if the transition from SP2 to SP1 results in a slight pressure over shoot.
It does not matter if there is still a deviation between SP1 and actual pressure.
Example:
Check control performance over the whole control range with parameters above.
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