Toyota 7BPUE15 Service Manual Download

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Section

9. Theory of Operation

Toyota Orderpicker Model

15 Service Manual

Closing

Switches

Closing
Switches

Stepping on the

pedal closes

switches S2

1) and S 2 3

2). Both switches must be closed to

travel,

and/or steer. If either switch

opens while traveling, the travel command to

the traction power amplifier stops and the
brake is applied.

1. With S2 closed, a circuit is completed

between JPC7-3 and

1 on the

carriage manager.

2. With S23 closed, a circuit is completed

between JPC7-6 and JPC7-4 on the
carriage manager.

3. With the S2

1) circuit complete,

the micro processor on the CM detects
that the switch is closed. The carriage
manager communicates to the

manager via the transmit

line that switch S2 is closed.

4. The

2 input from S23 is wired

directly through the mast cable from the
carriage manager

to the

manager

The CM

does not look a t the input or use it for
anything.

5. The

1 message and

input are received by the
manager and monitored continually to
ensure they both agree. If only one of the
switches closes while the pedal is
depressed the operator display indicates a
fault.

on the

manager

for

10) and

are lit when the switches are closed.

6. After the

manager

determines both

switches agree,

it turns on the PC contactor coil driver
which is indicated by a n LED

With

this coil driver on, a current path is
completed between

1 and

which energizes the PC

contactor coil.

7. The PC contactor tips close and battery

voltage is supplied to the following:

side of the open pump

contactor

tips,

MHA- 1 on the steer power head

Drive motor (MD) armature terminal

terminal of traction power amplifier

M- terminal of traction power amplifier

Drive motor (MD) armature terminal A2

sense a t

1 a s

FU 1 a s

and

a s PCSENSE

1 3 to pump contactor coil

terminal a s

13 to warning light a s

(optional)

8. The

manager also turns on

the brake coil driver which is indicated by
a n LED (IL6-4). With this coil driver on, a
current path is completed between

1 and

17 and the brake

releases. If the

switches are

opened during travel the brake will be
applied immediately.

9. After the truck has completed

self-diagnostics and the

pedal is

depressed, the STM looks a t the input

from the Home Reference Proximity
Sensor. If the prox is over metal, the STM
will turn the drive unit to the left. As soon

a s  the prox switch transitions from metal
to no metal the STM  removes the steer
command. If  it is not over metal, the drive
unit turns to the right. Once the home
prox transitions from off  to on, the STM
t u r n s  the drive unit back to the left until
the switch transitions to no metal and
removes the steer command. This position
is considered center and the position
register for the steer feedback encoder is
set to a zero reference point. During the
auto steer center function, the STM
monitors the steer feedback encoder and
the steer motor current to verify the drive
unit is actually powered and moving in the
proper direction. If  the STM  does not see
current or encoder pulses, a n  error code
displays. If  the STM  does not see a  home
reference proximity sensor transition, it