JLG 1250AJP Service Manual - Manual (Page 336)

SECTION 4 - BOOM & PLATFORM
4-96 – JLG Lift – 3121171
In order to obtain acceptable performance while perform-
ing 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, Tele-
scope, 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 = aux-
iliary 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 func-
tions
During the power-up procedure, function enable, in both
Platform and Ground Mode, is delayed during the 1.5 sec-
ond 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
manually 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
override 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.