Service Manual Instruction Manual

SECTION 4 - BOOM & PLATFORM
4-96 – JLG Lift – 3121171
In order to obtain acceptable performance while performing
all hydraulic functions, five sets of parameters are used. These
“zones” allow compensation for differences in how the basket
level changes when doing different functions. These zones are
as follows:
1. Lift up
2. Lift down
3. Other boom functions
4. Drive
5. Auxiliary
The other boom functions zone includes Swing, Telescope, Jib
swing (It is not necessary to level with jib lift, since the
mechanical linkage keeps the basket level).
These zones are prioritized when multiple functions are active.
The priorities are as follows.
1. Auxiliary power and any other function, zone = auxiliary
power
2. Drive and any other function, zone = Drive
3. Lift up and any other function, zone = Lift up
4. Lift down and any other function, zone = Lift down
5. Other boom functions, zone = Other boom functions
During the power-up procedure, function enable, in both Plat-
form and Ground Mode, is delayed during the 1.5 second
startup lamp test. During this 1.5 second startup period, the
basket level up valve will be energized at 100% duty cycle for
0.5 second, and then the basket level down valve energized at
100% duty cycle for 0.5 second. This will help to keep the
valves from sticking.
PLATFORM LEVEL MANUAL OVERRIDE
In addition to automatic leveling the operator is able to manu-
ally adjust the platform level position by means of the level
override switches located at the platform and ground control
positions (similar to a Master/Slave hydraulic system).
The level system assumes a new set point after a level over-
ride switch is operated. In other words the operator can chose
a platform level incline other than level with gravity and the
system will maintain this set point during automatic leveling.