Ulvac G-Tran Series, Instruction Manual

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11. TROUBLESHOOTING
One of the causes of malfunctioning of the sensor unit is erroneous electrical wiring. If
any trouble is suspected, check the following.
(1) Wiring between the sensor unit and remote host
(2) Wiring between the sensor unit and display unit (when display unit is used)
(3) Signal short/open
After checking these, take corrective actions referring to the table below. The arrow
marks → in the “Corrective action” columns indicate the pages to refer to.
Before taking these actions, turn off the power.
• Measurement does not start though power is supplied.
Possible cause Corrective action
Erroneous wiring or disconnection of power
cable
Correct the wiring and check continuity by a
circuit tester.
→
P. 7
Line voltage is below specified range. Check line voltage by a circuit tester. (Line
voltage : 24V ± 2V)
Fuse blown out To be repaired and checked at ULVAC
Failure of internal circuit To be repaired and checked at ULVAC
• Pressure has changed, but the pressure output remains constant.
Possible cause Corrective action
Pressure is below measurable range. Normal
Erroneous wiring or disconnection between
sensor unit and remote host
Correct the wiring and check continuity by a
circuit tester.
→
P. 7
Line voltage is low. Check line voltage by a circuit tester. (Line
voltage: 24V ± 2V)
• Voltage near 10 volts is outputted and does not change.
Possible cause Corrective action
Insulation failure between anode and
cathode because of conductive material
deposited between anode and cathode in
the sensor head.
Insulation failure caused by contact of
anode and cathode
Check insulation between the electrodes of the
sensor head using a Megger. The Megger
indication should be infinite or more.
If they are not insulated, remove the sensor
head and overhaul it. It may be necessary to
replace the sensor head with a new one
depending on the degree of deposition of
conductive material.
Insulating material or other is deposited in
the sensor head, making it difficult to set
up discharge.
Overhaul the sensor head. It may be necessary
to replace the sensor head with a new one
depending on the degree of deposition.
Erroneous wiring or disconnection between
sensor unit and remote host
Correct the wiring and check continuity by a
circuit tester.
Sensor head is not installed. Install a compatible sensor head.