Liquisys M CLM223/253
Maintenance
Hauser
85
8.1.5
Check of conductive sensors
• Measuring surface connection:
The measuring surfaces are directly connected to the connections of the sensor connector.
Check with ohmmeter at < 1
.
• Measuring surface shunt:
There may not be any shunt between the measuring surfaces.
Check with ohmmeter at > 20 M
.
• Temperature sensor shunt:
There may not be any shunt between the measuring surfaces and the temperature sensor.
Check with ohmmeter at > 20 M
.
• Temperature sensor:
You can find out the type of the temperature sensor being used by consulting the sensor
nameplate. The sensor can be checked at the sensor connector with an ohmmeter:
– Pt 100 at 25 °C (77 °F) = 109.79
– Pt 1000 at 25 °C (77 °F) = 1097.9
– NTC 10 k at 25 °C (77 °F) = 10 k
• Connection:
For sensors with a terminal connection (CLS12/13) check the assignment of the terminals
for reversals and the tightness of the terminal screws.
8.1.6
Check of inductive sensors
The following specifications apply to the CLS50, CLS52 and CLS54 sensors.
The sensor lines on the instrument or junction box are to be disconnected for all tests
described here!
• Testing transmitting and receiving coils
– Ohmic resistance
CLS50/52: approx. 0.5 to 2
CLS54: approx. 1 to 3
– Inductivity approx. 260 to 500 mH (at 2 kHz)
CLS50: approx. 250 to 450 mH
CLS52/54: approx. 180 to 550 mH
(Measure the white and red coaxial cables, between the inner conductor and screen in
both cases.)
• Testing the coil shunt
– A shunt between the two sensor coils is not allowed. The resistance measured should be
>20 M
.
Test with ohmmeter between red coaxial cable and white coaxial cable.
• Testing the temperature sensor
Use the table in chapter "Simulation of inductive sensors for device test" to check the
Pt 100 / Pt 1000 in the sensor.
Measure between the green and white wires and between green and yellow. The
resistance values should be identical.
• Testing the temperature sensor shunt
– Shunts between the temperature sensor and the coils are not allowed. Check with
ohmmeter for >20 M
.
Measure between the temperature sensor wires (green + white + yellow) and the coils (red
and white coaxial cables ).
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