VAT 642 GP Series Installation, Operating, & Maintenance Instructions page 54

3. Optimizing I gain
While optimizing I gain, the gas flow determined above has to be constant all the time.
Start with P gain set to half of the value found when optimizing P gain and set I gain to 1.0.
Keep the P gain constant.
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 if the valve position does not stabilize, I gain is
to high. If the transition results in a slow asymptotical pressure rise and there is still a constant deviation
to SP2, the I gain is too low.
The optimal value for I gain is found if the transition from SP2 to SP1 result in just a slight pressure over
shoot, a stable valve position and the actual pressure matches SP2 exactly.
Example:
4.7.2.1 Required information for support (in case of unsuccessful tuning procedure):
• Go to 'Tools / Create Diagnostic File' in 'Control View' resp. 'Control Performance Analyzer' and save
file
• Pressure / flow / gas conditions to be controlled
• Chamber volume
• Pumping speed (l/s) and pump type (e.g. turbo pump)
• System description
• Problem description
Send diagnostic file with and all required information to tuning-support@vat.ch
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INSTALLATION
Check control performance over the whole control range with parameters above.
Edition 2017-11-24
Series 642
605593EC