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Instruction Manual
Service
9
Calibration
9.1
Every InstruTech module is calibrated prior to shipment using nitrogen (N
adjusting zero (vacuum) and span (atmosphere) using the procedure described previously in
"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
-4
1 x 10
Torr. Care should be exercised when using gases other than nitrogen (N
9.2
Maintenance
In general, maintenance is not required for your InstruTech module. Periodic performance checks may be done by
comparing the gauge 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
Possible Cause
No power
The process gas is different from the gas
used to calibrate the CVM201
Module 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
section 4.2
-4
Torr to 1 x 10
-4
Torr, it is always a good
).
2
Possible Solution
Check power supply & power cable
Correct readings for different gas thermal
conductivity. See
gauge with different gases
Check that zero and span are adjusted
correctly
Check and tighten connections
Inspect gauge 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 to factory for possible cleaning
Replace sensor inside CVM201 module
Check setpoint setup
Replace sensor inside CVM201 module
Reduce pressure
Repair or replace CVM201 electronics
Return to factory for possible cleaning
Replace sensor inside CVM201 module
Replace sensor inside CVM201 module
Return to factory for possible cleaning
CVM201 Super Bee
titled
-3
Torr. If your
section 5
on using the
Page 27
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