JLG 800S Service Manual - Manual (Page 245)

SECTION 4 - BOOM & PLATFORM
3121139 – JLG Lift – 4-29
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 platform angle control, the opera-
tor is able to manually adjust the platform level position by
means of the level override switches located at the plat-
form and ground control positions (similar to a Master/
Slave hydraulic system).
If a command from the Platform Level Up and Down tog-
gle switch on either the platform or the ground is received,
automatic platform angle control will cease and the appro-
priate output will be commanded to turn on.
The duty cycle of the output shall be scaled from the
pump potentiometer. When the toggle switch is released,
after one second, the current filtered value of tilt angle will
be taken as the new set point.
In other words the operator can chose a platform level
incline other than level with gravity and the system will
maintain the chosen platform angle within several degrees
of setpoint.
Platform Leveling Fault
The JLG Control System takes a snapshot of the two sen-
sor values and records the difference once on each power
up. The Control system allows a ±5 degree difference
from those values. For example, if Sensor 1 is at 5
degrees and Sensor 2 is at 11 degrees, the difference is 6
degrees and the DTC is triggered when the sensors are 1
degree (or less) apart or 11 degrees (or more) apart.
If a fault occurs in the platform leveling system the follow-
ing will occur:
1. Automatic platform angle control will stop and the
platform dump valve will be disabled (level, rotate,
and jib functions disabled). The exception is when
there is a fault in only one sensor automatic platform
angle control will remain active as the control sys-
tem will use the other sensor to control leveling.
2. The level system fault lamp will flash (to indicate that
the leveling function has been lost).
3. The platform alarm will sound.
4. A system fault will be logged.
5. All function speeds (lift, swing, telescope and drive)
will be placed in creep mode (except when the plat-
form is in the transport position see below).
To reset the fault the emergency stop switch should be
recycled.
IF THE LEVEL SYSTEM FAULT INDICATOR REMAINS ILLUMI-
NATED, RETURN THE PLATFORM TO THE STOWED POSITION,
SHUT DOWN THE MACHINE, AND REPAIR THE LEVELING SYS-
TEM.
ERROR RESPONSE
If basket level varies from the current setpoint by ± 5.5°
for more than 2 seconds for large variations from setpoint
when the platform is not in the transport position, the con-
trols assume the system is not properly set up or has
degraded and initiate a fault.
When the unit is in the transport position and driving and
the current setpoint varies by ± 5.5° for more than 10 sec-
onds the events 1,2,3 & 4 above will occur. (note function
speeds will operate normally). Since the control system
can not anticipate all conditions under which a machine is
to be operated, these parameters have been chosen to
provide reasonable performance and safe operation. If an
error occurs, cycling the EMS will clear the fault. The oper-
ator should evaluate the operating situation and assess
his machine to determine the source of the fault.