Series 651  INSTALLATION 
 
605451EC  Edition 2014-07-10  57/
 
1.2  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: