Husqvarna Automower 210 C Technical Manual page 22

1. FUNCTION
When the Automower ® rests on a completely flat
surface, the values should be around +/-3. In other
cases, the tilt sensor must be calibrated (see 4.8.2
Manual test on page 68). If the mower tilts up and to
the left the values will be negative.
1.13.3 Lift sensor
The lift sensor is the sensor that senses whether the
mower is being raised off the ground. This is done with
the help of the mechanical device at the front of the
mower. If the "lift" signal is indicated, the mower and
the blade disc stop immediately. The mower will then
try free itself of the obstacle that caused it to lift of the
ground by backing up and turning several times.
1.13.4 Ultrasonic sensor (260 ACX)
The purpose of the ultrasonic sensors is to reduce the
mower's speed before a collision with obstacles that
are not protected by the boundary wire. The two
sensors on the mower detect objects at a distance of
approximately 50 cm (20") from the front edge of the
mower body and at a depth of up to 10 cm (4")above
the ground (the grass roots). The two sensors operate
independently of each other. At certain angles of
incidence, smooth and clean surfaces can sometimes
be difficult for the sensors to detect. In these cases,
the mower/sensors may entirely miss some objects
and collide with them without reducing speed. This is
nothing abnormal. Therefore, these types of objects
should be protected with the boundary wire.
Fault handling
If the mower collides with an object at a speed of
40 cm/sec (16"/sec) or higher, more than 5 times in a
row, the speed drops to 30 cm/sec (12"/sec) until the
mower is stopped or begins to mow again after
completed charging. When this is repeated in three
mowing cycles, one after the other, an SMS message
is sent "Check ultrasonic". For more information about
the mower's SMS function, see 1.14 SMS function on
page 23.
Strong rain and hard, smooth surfaces (e.g. flat
walkways) can also cause the mower to reduce speed.
If the mower runs at reduced speed, i.e. below
40 cm/sec (16"/sec) for more than 60 seconds, the
fault message "Check ultrasonic" appears on the
mower. However, the fault message only appears if the
mower is actively stopped while running at a reduced
speed and therefore does not constitute a real error in
the sense of the mower stopping. However, if this is
repeated in three mowing cycles, one after the other,
an SMS message is sent "Check ultrasonic".
In the event that the message "Check Ultrasonic"
appears, either via SMS or on the mower, the
ultrasonic sensors should be cleaned with a dry cloth
or similar, alternatively, a boundary wire should be
placed around objects that cannot be detected by the
ultrasound (and therefore generate the fault message).
22 - English