VAT 615 Series Installation, Operating, & Maintenance Instructions page 37

5. Calculate gas flow for learn with Pmax >1mbar.
q q
+
max min
q =
L
2
P = P
L max
Note:
If P > P the learn flow must be calculated according step 4 with P
L sfs
q = 39.5 P
L sfs
3.6.7.2 Fixed algorithm
For the fixed algorithm there are 2 configurations possible, Fixed PI downstream and Fixed PI upstream. It is possible to
switch between Fixed PI downstream and Fixed PI upstream. Refer to chapter: «Pressure control algorithm» for details.
Fixed algorithm is used if for any reason (e.g. too long system time constant) the adaptive control mode does not provide
satisfying control performance.
In Fixed algorithm the parameters P-Gain and I-Gain have to be set according to the systems characteristics.
This valve may be used for downstream or upstream pressure control depending on configuration. The Fixed algorithm
parameters of the pressure controller require correct adjustment. These parameters must be set once during system setup
and are stored in the device memory which is power fail save. Based on the Fixed algorithm controller configuration, the
valve is able to run fast and accurate pressure control cycles. The Fixed algorithm parameters can be evaluated using
below instruction.
Note: In downstream control direction valve will move towards open when current pressure is higher then set point.
In upstream control direction valve will move towards close when current pressure is higher then set point.
Local
'Control View' or 'Control Performance Analyzer'
Go to 'Tools / Terminal' menu and do the «Pressure
control configuration» refer to chapter: 3.6.7 Pressure
control configuration.
Note: To optimize Fixed algorithm of pressure controller refer to chapter «Tuning of pressure control performance».
VAT Vakuumventile AG, CH-9469 Haag, Switzerland
Tel +41 81 771 61 61 Fax +41 81 771 48 30 CH@vatvalve.com www.vatvalve.com
Installation, Operating & Maintenance Instructions
Series 615 DN 40 (I.D. 1½"), DeviceNet
gas flow for learn
q
L
max. process gas flow
q
max
min. process gas flow
q
min
gas flow for learn [sccm]
q
L
P sensor full scale [Torr]
sfs
C
R
C required lower conductance [l/s]
R
operation:
instead of P .
sfs max
Remote operation:
Note: It's not possible to do «Pressure control
configuration» via remote operation.
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