Husqvarna Automower 305 Technical Manual page 49

5�1�2 Circuit boards
There are three circuit boards in Automower® 305:
• Control box (1)
• MMI card (2)
• Front sensor card (3)
3
The circuit boards contain the electronics and
software required to control the mower's functions.
In simple terms this can be described as the control
box gathering in sensor signals that are evaluated
by the software and generating control signals to the
motors. The MMI-card collects its information from
keys that are pressed on the keypad and conveys
the menu selections that the user has made to the
control box, which saves them in its memory. These
selections subsequently become the conditions for
the control box to take into account in evaluating the
sensor signals. The MMI-card also has the task of
presenting information from the control box to the
display.
The control box and the MMI-card contain their own
separate software. After any of these cards are
changed they have to be programmed via Autocheck
EXP.
The front sensor card does not have any software,
and consequently does not need to be programmed
after a change.
5� REPAIR INSTRUCTIONS
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3020-019
5�1�3 Sensors
The Automower® 305 is equipped with the following
sensors:
• Collision sensor (1)
• Tilt sensor (2)
• Lift sensor (3)
• Rear loop sensor (4)
• Front loop sensor (5)
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5
The lift sensor and front loop sensor are mounted on
their own circuit board in the front part of the chassis'
lower section. The other sensors are mounted on the
control box in the lower section of the chassis.
The sensors cannot be repaired. If trouble shooting
shows that one of the sensors is defective, the entire
control box or front sensor card (depending on which
sensor is defective) must be replaced.
The front and rear loop sensors measure the signals
that the circuit board in the charging station transmits
in the boundary wire (A-signal), the guide wire
(guide-signal) and the charging station (F-signal).
The signals are used to steer the mower and keep
the mower inside the working area.
The lift sensor and the collision sensor measure the
magnetic field from the two permanent magnets that
are located in the body. If the magnetic field is too low
(the distance to the magnet increases) the control
box interprets it that a lift or collision has occurred.
The tilt sensor is an accelerometer positioned on the
control box. It measures the gradient in both X and
Y axis. The value is used, among other things, to
correct the speed of the drive wheels when mowing
on steep slopes.
The current value from the sensors can be read in
the display on the mower, as well as from Autocheck
EXP.
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3020-020
English - 47