Instruction Manual CVM201 Super Bee
InstruTech, Inc. Page 27
9 Service
9.1 Calibration
Every InstruTech module is calibrated prior to shipment using nitrogen (N
2
). However, you can calibrate the instrument by
adjusting zero (vacuum) and span (atmosphere) using the procedure described previously in section 4.2 titled
“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
-4
Torr to 1 x 10
-3
Torr. If your
minimum operating pressure is higher than 1 x 10
-3
Torr, it is not normally necessary to perform calibration at zero and thus
span calibration should be adequate. If you are able to evacuate your system to below 1 x 10
-4
Torr, it is always a good
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
Torr even though the system has been evacuated to below
1 x 10
-4
Torr. Care should be exercised when using gases other than nitrogen (N
2
).
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.
9.3 Troubleshooting
Check power supply & power cable
Readings appear very different from
expected pressure
The process gas is different from the gas
used to calibrate the CVM201
Correct readings for different gas thermal
conductivity. See section 5 on using the
gauge with different gases
Module has not been calibrated or has
been calibrated incorrectly
Check that zero and span are adjusted
correctly
Readings are noisy or erratic
Loose cables or connections
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
Gauge cannot be calibrated - zero and span
can’t be adjusted
Contamination
Sensor failure for other cause
Return to factory for possible cleaning
Replace sensor inside CVM201 module
Setpoint does not actuate
Display shows “Sensor Bad”
Replace sensor inside CVM201 module
Display shows “overpressure”
System pressure over 1000 Torr
Faulty electronics
Reduce pressure
Repair or replace CVM201 electronics
Atmospheric pressure reads too high and
can’t be set to correct value
Contamination
Sensor wire damaged
Return to factory for possible cleaning
Replace sensor inside CVM201 module
Atmospheric pressure reads too low and
can’t be set to correct value
Sensor wire damaged
Contamination
Replace sensor inside CVM201 module
Return to factory for possible cleaning
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