Section
9.
Theory of Operation Toyota Orderpicker Model
7BPUE
15 Service Manual
Closing
Deadman Switches
Closing Deadman
Switches
Stepping on the deadman pedal closes
deadman switches S2 (Deadman 1) and S23
(Deadman 2). Both switches must be closed to
travel,
lift/lower 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 JPC7- 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
(Deadman 1) circuit complete,
the micro processor on the CM detects
that the switch is closed. The carriage
manager communicates to the
steer/tractor manager via the transmit
line that switch S2 is closed.
4. The
Deadman 2 input from S23 is wired
directly through the mast cable from the
carriage manager
(JPC8-5) to the
steer/tractor manager (JPT9-5). The CM
does not look at the input or use it for
anything.
5. The
Deadman 1 message and Deadman 2
input are received by the
steer/tractor
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.
LEDs on the steer/tractor manager
for
Deadman 1 (IL6- 10) and Deadman 2
(IL2) are lit when the switches are closed.
6. After the
steer/tractor manager
determines both
Deadman switches agree,
it turns on the PC contactor coil driver
which is indicated by an LED
(IL6-8). With
this coil driver on, a current path is
completed between
JFT12-2 1 and
JFT12-20 which energizes the PC
contactor coil.
7. The PC contactor tips close and battery
voltage is supplied to the following:
TPl,TP2
B+ side of the open pump (P) contactor
tips,
P-1
MHA
-
1 on the steer power head
Drive motor (MD) armature terminal A1
B+ terminal of traction power amplifier
M
-
terminal of traction power amplifier
Drive motor (MD) armature terminal A2
MDA2 sense at JPT11-7
JPT12- 1 as B+PC
FU 1 as B+PC and B+PCF
JPT12-2 as PCSENSE
JPT12- 13 to pump contactor coil
(X)
terminal as B+PCF
JFT12- 13 to warning light as B+PCF
(optional)
8.
The steer/tractor manager also turns on
the brake coil driver which is indicated by
an LED (IL6
-
4). With this coil driver on, a
current path is completed between
JPT12-2 1 and JPT12- 17 and the brake
releases. If the
Deadman switches are
opened during travel the brake will be
applied immediately.
9.
After the truck has completed
self
-
diagnostics and the deadman pedal is
depressed, the STM looks at 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
as 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
turns 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, an error code
displays. If the STM does not see a home
reference proximity sensor transition, it
00700
-
CL222
-
05,
1
5
March 2005
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