VEGA Capacitive electrodes EL 4 … 20 mA - Compact - Manual (Page 41)

Capacitive electrodes EL 4 … 20 mA - Compact 41
22652-EN-020809
Diagnosis
Contact 4 and vessel
The connection between contact 4 and the metal vessel (not instrument
hexagon or electrode flange) should be as good as possible. Measure
with an ohmmeter (range very low) the resistance value between contact
4 and the vessel.
• Short-circuit (0 … 3 Ohm), optimum connection
• Resistance > 3 Ohm
- corrosion on the mounting thread or flange
- possibly the mounting thread was covered with Teflon tape or a
similar material
Check the connection to the vessel. If there is no connection, you can
connect a cable from the external grounding terminal to the vessel. Make
sure that coated flanges are always connected via the grounding termi-
nal to the vessel.
Contact 4 and 6
Values > 3 Ohm indicate a defect.
If you cannot find a failure in the electrode, then replace the oscillator with
a similar type (if available) or send the electrode for repair to VEGA.
After replacement of the electronics, a fresh adjustment must be carried
out. See 4 Setup
VVO
error message
Invalid measured
value
Invalid measured value
The current measured value is outside the valid measuring range.
Causes can be e.g. considerable changes of the DK value or incorrect
settings.
Change the current measuring conditions.
Instrument error
An error in the sensor was found.
Possible causes are:
- supply voltage not within tolerance
- defective oscillator
- damage to the electrode or to the insulation
- electrode short-circuited against vessel wall
• Separate the sensor from power supply and then reconnect (cold
start).
• If the error message does not extinguish, check the sensor cable and
the power supply.
• If the error message does not extinguish, check the sensor for visible
damage.
If you cannot find any faults, please call our service department.
VVO
error message
Instrument error