5 Convectron Gauge Module
57
Series 330 Vacuum Gauge Controller
Instruction Manual - 330004 - Rev. 02
5.6 Convectron Troubleshooting
5.6.1 Convectron Gauge Test Procedure
The small diameter sensor wire can be damaged by small voltages. Do not perform electrical
continuity tests with instruments applying in excess of 1 volt when the gauge is at vacuum, or 5 V
when at atmospheric pressure.
The Convectron gauge should show the following resistances (pin numbers are embossed on the
gauge connector):
NOTE: If the resistance values shown here are correct, but you still think the
gauge is not reading correctly, the gold plating on the sensor wire may be
eroded and the gauge will have to be replaced.
5.7 Convectron
Troubleshooting Guide
Figure 5-14
Convectron Gauge Connector
Table 5-2 Troubleshooting Guide
Symptom
Possible Cause
CGA Overcurrent LED is illuminated*
Cable short, pins 1-3 on CGA
CGB Overcurrent LED is illuminated*
Cable short, pins 1-3 on CGB
CGA or CGB Bridge Circuit LED is illuminated*
Bridge amplifier circuit failure
CGA Gauge Unplugged LED is illuminated*
CGA unplugged or a broken sensor wire.
CGB Gauge Unplugged LED is illuminated*
CGB unplugged or a broken sensor wire
Microprocessor Failure LED is illuminated or flashing*
Microprocessor failure
A/D Failure LED is illuminated or flashing*
A/D integration failure
Pressure reading very inaccurate
Controller out of calibration, unknown gas type,
gauge mounted in the wrong orientation, sensor
damaged (e.g., by reactive gas), gauge very dirty,
extremes of temperature or mechanical vibration.
* Refer to Figure 5-1 for component locations.
• Pins 1 to 2: 19 to 22 ohms
• Pins 2 to 3: 50 to 60 ohms
• Pins 1 to 5: 180 to 185 ohms
If the resistance from pins 1 to 2 reads about 800 ohms,
the sensor wire in the gauge is broken. Replace the
gauge tube.
Summary of Contents for Series 330
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