Stihl SMI 50, Instruction Manual, Page: 15 / 56

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English 7 Troubleshooting
7.1 Troubleshooting the Soil Moisture Sensor
7 Troubleshooting
Condition Cause Remedy
No output signal from
sensor.
Cable is not properly connected. ► Connect cable correctly.
Cable is damaged. ► Replace the soil moisture sensor.
Cable extension is not correct. ► Extend the cable correctly,
@
4.2.
Soil moisture sensor does
not show correct reading
or does not trigger correct
reaction from irrigation
controller.
There is an air gap between the sensor
and soil.
► Bury the soil moisture sensor completely and
correctly.
Cable extension is not correct. ► Extend the cable correctly,
@
4.2.
Cable has been extended correctly but is
too long.
► Do not extend cable beyond maximum length of
100 meters,
@
4.2.
Cable has been extended but contacts
have not been properly insulated.
► Extend the cable correctly and insulate contacts
properly against soil moisture,
@
4.2.
Soil moisture sensor is buried in a plant
pot that is too small.
► Bury the sensor in a plant pot with a volume of at
least 1 liter and at a distance of at least 5 cm from
the side.
Soil moisture sensor
shows incorrect moisture
reading in frosty
conditions.
Sensor reacts to liquid water in soil.
Liquid water turns to ice in frosty
conditions. Soil moisture sensor cannot
produce correct measurements.
► Repeat measurement at a temperature above
freezing. It makes no sense to perform
measurements or irrigation at temperatures below
freezing.
► If the soil moisture sensor continues to show an
incorrect moisture reading: Replace the soil
moisture sensor.
The sensor is defective.