VAT 65040 Series

Installation, Operating & Maintenance Instructions
Series 650, DN 100 – 250 (I.D. 4" - 10")
VAT Vakuumventile AG, CH-9469 Haag, Switzerland
Tel ++41 81 771 61 61 Fax ++41 81 771 48 30 Email reception@vat.ch www.vatvalve.com
258550EE
2007-05-11
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3.10 Pressure control
To prepare valve for PRESSURE CONTROL perform complete «3.6 Setup procedure».
The valve has parameters that may be modified to tune pressure control performance.
Refer to «3.10.2 Tuning of control performance».
The included PID controller controls the chamber pressure according to the pressure setpoint by means of the valve
position. The PID controller works with an adaptive algorithm to achieve best results under altering conditions (gasflow,
gas type).
Local operation:
(‘Control View’ resp. ‘Control Performance Analyzer’)
Remote operation:
(Refer to chapter «3.11.2 Digital inputs» and «3.11.4
Analog inputs and outputs» for details)
1. Set CONTROL MODE to PRESSURE CONTROL
Select or enter pressure setpoint
2. Set pressure SETPOINT
Note: In case CLOSE VALVE, OPEN VALVE or HOLD is also set these have higher priority.
3.10.1 Pressure control operation with 2 sensors
[applicable with 650 . . - . . . E - . . . . version only]
If 2 sensor operation is enabled, changeover between the sensors is done automatically during pressure control. For
configuration refer to chapter «3.6 Setup procedure». We recommend a ratio of 10:1 between the pressure gauges. Max.
ratio is 100:1. High range respectively low range pressure gauge may be either connected to sensor 1 or sensor 2 input.
It’s required to do correct sensor configuration.
Between 90 and 100% of the low range sensor full scale, the low range sensor is phased out while high range sensor is
phased in during pressure rise. During pressure decrease the high range sensor is phased out while low range sensor is
phased in. This maintains a functional response behavior in case of small calibration errors between the two sensors. The
PRESSURE output in this range is a blend between both sensors.
Note: Make sure that both sensors are calibrated.
Note: Do not close optional gauge isolation valves during the transition phase between the sensors.
3.10.2 Tuning of control performance
Normally the default settings will result in good pressure control performance. For some applications tuning may be
required to improve performance.
The tuning procedures for each parameter (grey boxes) and its default values are described separately below. Strictly
keep the procedure order.