Troubleshooting/Faqs; Sensor Check - Siemens SITRANS F M MAG 3100 Operating Instructions Manual

Troubleshooting/FAQs

7.1

Sensor check

Requirement
To check the SITRANS F M sensors the following test instruments will be required:
● Digital Meter/Multimeter
● Megger
● (Moving Coil Meter)
Sensor check
Remove the transmitter from the sensor or remote position before making the following
checks.
Coil resistance check
● Measure the coil resistance between connection numbers 85 and 86 using a digital
A low reading may indicate moisture within the coil housing or shorted coil tums.
A high reading would indicate an open circuit coil.
NOTICE
In case of deviation from nominal coil values, the sensor is damaged and must be replaced
Coil insulation check
Potential hazard!
Non-ex installations only!
● Megger between connection number 85 and the sensor body.
A low megger reading would indicate the coil insulation is braking down. This is normally due
to fluid ingress into the coil housing.
SITRANS F M MAG 3100
Operating Instructions, 06/2010, A5E03005599-01
meter.
Resistance should be around 100 ohms ±10 ohms. (See Coil resistence table)
WARNING
The resistance should be above 20 Megohms.
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