Installation, Operating & Maintenance Instructions
Series 612 DN 40-50 (I.D. 1.5“ - 2”), Logic
VAT Vakuumventile AG, CH-9469 Haag, Switzerland
Tel +41 81 771 61 61 Fax +41 81 771 48 30 [email protected] www.vatvalve.com
289419EB
2011-12-12
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3.10.1 Operation with 2 sensors
[applicable with 612 . . - . . . E - . . . . 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. It is required that the high range pressure gauge is connected to sensor 1 input and the low range pressure
gauge to the sensor 2 input.
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. 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.
Note: Make sure that both sensors are calibrated.
Note: Do not close optional gauge isolation valves during the transition phase between the sensors.
Example of PRESSURE and SENSOR READING allocation:
Above picture shows a 2 sensor system. In this configuration sensor 2 covers low range (100 mTorr) and sensor 1 covers
high range (1 Torr).
Switchover between sensors is done automatically according to «Pressure control operation with 2 sensors».
0-1
0
V
High range
sensor
Low range
sensor
0-
10V
SENSOR 1
100 mTorr
1 Torr
0 mTorr
SENSOR 2
PRESSURE
0 – 1’000'000
