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Instruction Manual
9 Service
9.1 Calibration
Every InstruTech gauge is calibrated prior to shipment using nitrogen (N
adjusting zero and span (atmosphere) using the procedure described previously in the "Setup and Operation" section (also
see User Interface Map). Zero and span (atmosphere) calibration affect the displayed value and the output signal. Zero
calibration optimizes performance of the gauge when operating at a low pressure range of 1 x 10
your minimum operating pressure is higher than 1 x 10
thus span calibration should be adequate. If you are able to evacuate your system to below 1 x 10
practice to check and set zero if necessary. This will also improve performance in cases where gauge contamination is
causing higher readings than 1 x 10
be exercised when using gases other than nitrogen (N
9.2 Maintenance
In general, maintenance is not required for your InstruTech gauge and controller. Periodic performance checks may be
done by comparing the gauge to a known reference standard.
9.3 Troubleshooting
Indication
Display is off / blank
Readings appear very different from
expected pressure
Readings are noisy or erratic
Gauge cannot be calibrated - zero and span
can't be adjusted
Setpoint does not actuate
Display shows "Sensor Bad"
Display shows "overpressure"
Atmospheric pressure reads too high and
can't be set to correct value
Atmospheric pressure reads too low and
can't be set to correct value
InstruTech, Inc.
-3
Torr, it is not normally necessary to perform calibration at zero and
-4
Torr even though the system has been evacuated to below 1 x 10
) / air.
2
Possible Cause
No power
The process gas is different from the
gas used to calibrate the CVG101 gauge
CVG101 gauge has not been calibrated
or has been calibrated incorrectly
Loose cables or connections
Contamination
Vibration
Contamination
Sensor failure for other cause
Incorrect setup
Sensor wire damaged
System pressure over 1000 Torr
Faulty electronics
Contamination
Sensor wire damaged
Sensor wire damaged
Contamination
). However, you can calibrate the instrument by
2
-4
Possible Solution
Check power supply & power cable
Correct readings for different gas thermal
conductivity. See section on using the gauge on
different gases
Check that zero and span are adjusted
correctly
Check and tighten connections.
Inspect CVG101 for signs of contamination
such as particles, deposits, discoloration on
gauge inlet. Return to factory for possible
cleaning
Ensure gauge is not mounted where excessive
vibration is present
Return CVG101 to factory for possible cleaning
Replace CVG101 gauge
Check setpoint setup
Replace CVG101 gauge
Reduce pressure
Repair or replace VGC301 electronics
Return CVG101 to factory for possible cleaning
Replace CVG101 gauge
Replace CVG101 gauge
Return CVG101 to factory for possible cleaning
VGC301A Controller
-3
Torr to 1 x 10
Torr. If
-4
Torr, it is always a good
-4
Torr. Care should
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