Pressure Control; Pressure Control Operation With 2 Sensors - VAT 615 Series Installation, Operating, & Maintenance Instructions

3.10 Pressure control

To prepare valve for PRESSURE CONTROL perform complete «Setup procedure».
The valve has parameters that may be modified to tune pressure control performance.
Refer to «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).
('Control View' resp. 'Control Performance Analyzer')
Select or enter pressure setpoint

3.10.1 Pressure control operation with 2 sensors

[applicable with 615 . . - . . . Q - . . . . version only]
If 2 sensor operation is enabled, changeover between the sensors is done automatically during pressure control. For
configuration refer to chapter «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.
For monitoring purpose each sensor signal may be read out individually. Refer to «Explicit messaging inquiry commands
SENSOR 1 READING and SENSOR 2 READING».
Note: Make sure that both sensors are calibrated.
Note: Do not close optional gauge isolation valves during the transition phase between the sensors.
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 40-50 (I.D. 1.5" - 2"), DeviceNet
Local operation:
Remote
(Refer to chapter «Explicit messaging control
commands» for details)
1. Send EXECUTING
(if not yet selected)
2. Send SETPOINT TYPE
= pressure control
3. Send CONTROL MODE for pressure
= control mode
4. Send PRESSURE SETPOINT
operation:
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2011-11-24