JLG 1100S Service Manual - Manual (Page 46)

SECTION 3 - CHASSIS & TURNTABLE
3-4 – JLG Lift – 3121256
will allow the operator to move the machine until it can be
repaired. The wheel at the failed sensor will be driven
based on the information available from the other sensors.
This wheel will not track perfectly and will become farther
out of position over time. When the wheel becomes pro-
hibitively out of position, the wheels can be re synchro-
nized by fully steering against the mechanical stops.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.
3.6 DRIVE/STEERING SPEED CONTROL
The Drive/Steering Speed Control system uses the steer-
ing sensors from the steering control system to increase
operator control and comfort by reducing the effect of
turning the chassis on the resulting lateral platform speed.
The system proportionally varies the drive speed based
on the predicted turning radius of the chassis for both
coordinated and conventional two wheel steer modes.
The tighter the turn the slower the allowable drive speed.
As crab steer does not steer on a radius, full drive speed is
maintained regardless of steer angle.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.
3.7 TRACTION CONTROL SYSTEM
The traction control system uses the steering sensors
from the steering control system to optimize the perfor-
mance of the drive system. This is especially important
due to the disparity of wheel speeds generated between
the inside and outside wheels of the extended axle chas-
sis with large steering angle capability. The steering sen-
sors are used to predict the rolling path and therefore the
required wheel speed of each wheel as the steering
angles change and steering modes change. The control
system can then command the ideal flow from each of the
two drive pumps, one for the right side of the machine and
one for he left side. On 1100SJP machines, two flow divid-
ers, one for the right side front to back and one for the left
side front to back absorb the variation in wheel speed
front to back.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.
3.8 DRIVE ORIENTATION SYSTEM
The Drive Orientation System (DOS) is intended to indi-
cate to the operator conditions that could make the direc-
tion of movement of the chassis different than the
direction of movement of the drive/steer control handle.
The system indicates to the operator the need to match
the black and white directional arrows on the platform
control panel to the arrows on the chassis. The system
uses a proximity switch mounted on the hydraulic swivel,
an indicator light and an override switch on the platform
display panel. The proximity switch trips when the turnta-
ble is swung +/- 45 degrees off center of the normal driv-
ing position. This occurs roughly when the boom is swung
past a rear tire. When the turntable is in the normal drive
position with the boom between the rear tires, no indica-
tions or interlocks are made. When the machine is actively
driving when the turntable is swung past the switch point,
the system is ignored until drive/steer is released. When
drive is initiated with the boom swung past the switch
point, the DOS indicator will flash and the drive/steer func-
tions will be disabled. The operator must engage the DOS
override switch to enable Drive/steer (high drive will
remain disabled). When the DOS is enabled, the DOS
indicator will be illuminated continuously and a 3-second
enable timer will be started and will continue for 3 sec-
onds after the end the last drive/steer command. If the
timer expires, the DOS override switch must be re-
engaged to enable drive/steer.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.