JLG 1250AJP Operator Manual - Manual (Page 59)

SECTION 4 - MACHINE OPERATION
3121170 – JLG Lift – 4-5
Automatic Main Boom Control System
During combined tower lift and main lift functions, the control
system will maintain the tower lift speed and automatically vary
the maximum main lift command as needed to compensate for
the movement of the tower.
The interaction of the main boom and the tower boom is slightly
different when the main boom is above or below 60° relative to
gravity.
TOWER LIFT UP/DOWN - MAIN BOOM BELOW 60°
During tower lift up or down with the main boom below 60°, the
control system will maintain the angle of the main boom read at
the start of the tower lift command or as read at the conclusion of
main lift during combined tower and main lift commands.
TOWER LIFT DOWN - MAIN BOOM ABOVE 60°
During tower lift down with the main boom initially above 60°,
the control system will lower the main boom to approximately
60° before starting tower movement. The control system will then
control the main boom to 60° for the remainder of the tower lift
down command.
TOWER LIFT UP - MAIN BOOM ABOVE 60°
During tower lift up with the main boom already above 60°, the
control system will delay automatic compensation of the main
boom angle during tower lift until the main boom reaches
approximately 60°. The control system will then control the main
boom to 60° until the tower boom has reached its maximum
height. Continuing to operate the tower lift up when the tower
reaches its maximum height will cause the control system to
automatically raise the main boom to its original angle.
Slow Down System
The control system uses the envelope control sensors to auto-
matically slow down the tower lift up and tower lift down at the
top of the tower path and to automatically slow down main lift
up and main lift down as the minimum and maximum angles of
the working envelope are approached. The control system indi-
cates to the operator this slow down by flashing the creep light
on the platform display. This applies to both platform and ground
controls, however, no indication is made on the ground control
panel.