Toyota 7BPUE15 Service Manual page 303

Section 8. Wire Guidance
Theory Operation
of
The steer controller monitors the direction of
travel (forward and reverse) by monitoring the
travel speed encoder. This encoder is mounted
on top of the drive motor and turns with the
armature shaft. As the encoder turns, it sends
two voltages, SPEEDFB A and SPEEDFB B, to
the steer controller. SPEEDFB A and SPEEDFB
B will change state from approximately
to 0 volts and back a s the encoder is rotated.
SPEEDFB A changing state before SPEEDFB B
indicates one direction of travel. SPEEDFB B
changing state before SPEEDFB A indicates the
opposite direction of travel.
The steer controller must monitor both travel
directions to keep the truck on the guide wire.
The steer request for a truck traveling
tractor-first is opposite to the steer request
when the truck travels forks-first. The steer
controller reverses the steer request a s the
travel direction changes.
The travel speed encoder also indicates the
travel speed to the steer controller. The steer
controller monitors the speed to allow smooth
steering changes a t all travel speeds.
Toyota Orderpicker Model 7BPUE15 Service Manual
volts
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00700-CL222-05, 1 5 March 2005