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Instruction Manual
Service
9
Calibration
9.1
Every InstruTech CVG101 sensor is calibrated prior to shipment using nitrogen (N
instrument by adjusting zero and span (atmosphere) using the procedure described
"Programming".
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
minimum operating pressure is higher than 1 x 10
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 sensor and controller. Periodic performance checks may be
done by comparing the sensor to a known reference standard.
Troubleshooting
9.3
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 thus
-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
VGC301 Controller
). However, you can calibrate the
2
previously in section 4.2 titled
-4
-3
Torr to 1 x 10
Torr. If your
-4
Torr, it is always a good
-4
Torr. Care should
Possible Solution
Check power supply & power cable
Correct readings for different gas thermal
conductivity. See
section 5
on using the gauge with
different gases
Check that zero and span are adjusted correctly
Check and tighten connections
Inspect the 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 the CVG101 to factory for possible cleaning
Replace the CVG101
Check setpoint setup
Replace the CVG101
Reduce pressure
Repair or replace the VGC301 electronics
Return the CVG101 to factory for possible cleaning
Replace the CVG101
Replace the CVG101
Return the CVG101 to factory for possible cleaning
Page 38
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