Cst-Drive Mode Logging; Manual Drive Mode Logging; Keypad Buttons; Main Relay - Husqvarna 967187001 Workshop Manual

CST-drive mode logging

12.1 Manual Drive Mode Logging

Using CST drive mode logging, the machine can
be operated while looking at what is happen-
ing with the various signals on the screen. This
assumes the machine is connected to a laptop
computer. As with the other tests, the computer is
connected to CCU via a USB cable and the CST
software is running on the computer.
If logging is to function properly, it must be started
by pressing the start button in the software. It is
now possible to see what is happening with the
various signals while activating and driving around
on the machine.

12.2 Keypad Buttons

Keypad buttons

Shown here are the two pushbuttons on the control
panel, the pushbutton for activating (I) and the but-
ton for savE mode (e). These change color (green)
when activated to indicate that the signals have
reached CCU.

12.3 Main Relay

Main relay

This test requires that the machine is activated with the
activation button in order to obtain accurate test results.
Refer to the workshop manual for a detailed explanation
how to read the results.
Main relay driver circuit on
Main relay driver circuit on
Main relay driver circuit on
Once the machine as been activated using the
key switch and then the activating button (I), two
relays are triggered. The first relay has no support
in CST, it is deactivated with the key switch. The
relay can be heard clicking in the machine when
the key switch is turned to on position. When the
machine is later activated with the (I) button, the
next relay will be energized if everything is OK.
It is this relay that is called Main Relay in CST. If
everything is OK, the three colored rings will turn
green in the Main Relay box. If any ring should turn
red when attempting to activate the machine while
the relay is not activated, the relay circuit must be
checked.
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12.4 Troubleshooting the Main Relay

Inside CCU is a drive circuit that couples one side
of the relay's activation coil to GND. This circuit is
called driver circuit in the Main Relay box in CST.
If the first row under the main relay (Main Relay
driver circuit on) shows green, it means CST has
detected the driver has activated the machine with
the (I) button. If the output from CCU then couples
the relay coil to GND and conducts current, the
next ring will turn green (Main Relay driver circuit
status). If everything is OK, the third ring should
also turn green indicating the status of the drive
circuit inside CCU.
CCU couples the output to GND so that the relay
coil current is able to go to GND. This relay coil is
then coupled to plus 36 V on the other side of the
coil via the drive motor electronics. The signal from
the drive motor is interlocked (passes relay con-
nectors in the relay activated by the key switch) by
the switching power relay so that it must first be
energized before the main relay can be activated
by the drive motor and CCU. The switching power
relay is activated with a key, which energizes
the switching relay coil when switched on while
the drive motor is supplied on its input (Batt key
switch). Drive motor electronics now couples plus
36 V to the main relay coil when the engine control
capacitors are charged, approximately 500 ms
after the key has been turned to on. After pressing
the activation button (I) on the control panel, CCU
couples its output C:7 brown lead to GND. A cur-
rent then flows through the relay coil from the CCU
drive motor. The relay energizes if the motor has
finished charging its capacitors. Normally, the drive
motor has finished charging its capacitors when
pressing the activation button as charging capaci-
tors should take about 500 ms (half a second) after
turning the key to on. If the relay does not energize
after pressing the activation button, you can mea-
sure the brown lead from the drive motor that is
connected to the relay to check that it is +36 V out
from the motor to the relay.