VEGA Capacitive electrodes EK 4 … 20 mA - Compact - Manual (Page 38)

38 Capacitive electrodes EK 4 … 20 mA - Compact
22574-EN-020809
Diagnosis
Fault Rectifying measure
Sensor defective, Test the internal connections:
Measurement does • Loosen the 4 screws of the housing cover with a Phillips screw-
react to level driver and remove the housing cover.
changes • Loosen the two small screws with a Phillips screwdriver and pull the
oscillator out of the housing.
• Measure with an ohmmeter (range MOhm) the resistance values
between the following contacts:
C
M
- Capacitor
4
6
C
M
1 M
Screen
Contact 4 and middle pin (1)
The resistance must be 1 MOhm.
If the resistance is less, it indicates moisture in the housing or a defect in
the electrode insulation. A possible reason could be a non-insulated
electrode used in a conductive (moist) medium.
If the resistance is higher or if the connection is interrupted, the reason is
usually a bonding failure in the adapter plate or a defective resistor due
to strong electrostatic discharge.
In both cases, return the electrode to VEGA for repair.