Installation, Operating & Maintenance Instructions 
Series 650 DN 100-250 (I.D. 4“ - 10”), CC-Link 
 
 
 
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 
280672EB 
2010-12-15 
74/94 
 
 
Failure  Check  Action 
- Sensor(s) connected?  -  Refer to «Electrical connection». 
-  2 sensor version present at 
valve controller? 
-  Check valve version on page 1. Verify configuration. Refer 
to «Setup procedure». 
-  Refer to «Pressure control operation with 2 sensors». 
- ZERO done?  -  Perform ZERO when base pressure is reached. Refer to 
«ZERO» for details. 
Pressure reading is wrong 
or 
pressure reading is negative
 
-  Does sensor power supply 
provide enough power for 
sensor(s)? 
-  Verify sensor supply voltage. 
-  Valve in open position, check 
for O on display? 
-  OPEN VALVE and bring chamber to base pressure before 
performing ZERO. 
ZERO does not work 
- ZERO disabled?  -  Enable ZERO. 
Refer to «Valve and sensor configuration» for details. 
- Sensor voltage shifting?  -  Wait until sensor does not shift any more before 
performing ZERO. 
-  System pumped to base 
pressure? 
-  OPEN VALVE and bring chamber to base pressure before 
performing ZERO. 
Pressure is not ‘0’ after ZERO 
-  Sensor offset voltage 
exceeds ±1.4V 
- Replace pressure gauge. 
-  Safety mode active, check for 
D on display? 
-  Provide power to motor to allow for operation.  
-  Refer to «Electrical connection» for details. 
- PRESSURE CONTROL 
selected, check for P on 
display? 
-  Select PRESSURE CONTROL mode.  
Refer to «Pressure control» for details. 
PRESSURE CONTROL does not 
work
 
- LEARN done?  - Perform LEARN. 
Refer to «Setup procedure» for details. 
- Setup done completely?  -  Perform «Setup procedure» completely. 
- LEARN done?  - Perform LEARN. 
Refer to «LEARN» for details. 
- ZERO performed before 
LEARN?  
-  Perform ZERO then repeat LEARN. 
Refer to «Setup procedure» for details. 
- LEARN interrupted?  -  Repeat LEARN.  
Refer to «LEARN» for details. 
-  Was gas flow stable during 
LEARN? 
-  Repeat LEARN with stable gas flow. 
Refer to «LEARN» for details. 
- Tuning done?  -  Tune valve for application. 
-  Refer to «Tuning of control performance» for details. 
-  Is sensor range suited for 
application? 
-  Use a sensor with suitable range (controlled pressure 
should be >3% and < 98% of sensor full scale). 
PRESSURE CONTROL not optimal 
-  Noise on sensor signal?  -  Make sure a shielded sensor cable is used.