VAT 615 Series Installation, Operating, & Maintenance Instructions page 44

3.11.1.3 Setpoint ramp adjustment
Setpoint ramp time effects:
Undershoot and overshoot of pressure
Response time
Default value for Setpoint Ramp is 1. Adjustment range for Setpoint Ramp is from 0 to 1000000.0 s.
This parameter defines the time that is used to decrease / raise pressure between 2 setpoints. Especially in pressure
decrease situations at low flows pressure response can be improved much by adapting setpoint ramp time.
Pressure chart
Without setpoint ramp optimizing
P
SF
S
P
START
P
EN
D
Choose the applicable formula depending on units you are familiar with.
t = Setpoint Ramp (s)
Adjustment procedure:
1. Start with optimal gain factor and sensor delay time according to preceding tuning steps.
2. Control a typical pressure / flow situation.
3. Control a lower pressure.
4. Repeat from step 2 with longer setpoint ramps until best response is achieved.
5. Verify pressure control response for a setpoint raise situation.
Note: In case a long ramp time is required to get optimal performance for pressure decrease situations it may be of
advantage to apply different settings for decrease / raise control situations.
Local operation:
('Control View', 'Control Performance Analyzer' or
Go to 'Setup / Control Parameter' menu.
Select setpoint ramp.
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
'Service Box 2')
With setpoint ramp optimizing
t
Remote
(Refer to chapter «S-Singel Stage Controller Object»
for details)
Send PID CONTROLLER SETPOINT RAMP
operation:
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2013-07-25