Siemens SITRANS F M MAG 3100 sensor Operating Instructions Manual page 46

Troubleshooting/FAQs
7.1 Sensor check
Electrode resistance check
● Measure the electrode resistance between connections 82 and 0 with a moving coil
● Repeat the resistance measurements between connections 83 and 0.
If the resistance is low there may be a short on the electrodes or wiring (in the case of a
remote mounted transmitter). Alternatively there may be water ingress or moisture in the
terminal box.
If the resistance is high and the pipe is completely full of fluid check the following:
1. Fluid is electrically conductive.
2. Electrodes are not coated with grease or any deposit.
3. Electrode circuit is not open.
4. Remote mounted transmitter has a 3 core cable with an overall shield continuously from
5. Shield is connected to 0 or to earth terminal (PE) on sensor.
Note
Sensors removed from line
For sensors removed from line with dry bore, use megger between terminal 82 and
compression plate, and 83 and compression plate to show any water ingress behind
electrodes or within enclosure.
44
meter.
With a sensor full of fluid the resistance should be between 5 KΩ and 50 KΩ.
If the sensor is empty the resistance will be infinite.
The results should be the same.
sensor to transmitter, including junction boxes and terminal rails inside panels.
SITRANS F M MAG 3100 sensor
Operating Instructions, 09/2012, A5E03005599-02