JLG 1850SJ, Service And Maintenance Manual, Page: 541 / 712

SECTION 6 - JLG CONTROL SYSTEM
3121619 6-109
6.14 ELECTRONIC PLATFORM LEVELING
Platform Leveling Fault Warning
The JLG Control System takes a snapshot of the two sensor val-
ues and records the difference once on each power up. The
Control system allows a ±5 degree difference from those val-
ues. 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 trig-
gered 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 following
will occur:
1. Automatic platform leveling will stop (except when
there is a fault in only one sensor automatic leveling will
remain active as the control system will use the other
sensor to control leveling)
2. The level fault lamp will flash
3. The audible alarm will sound
4. All functions will default to creep speed if the platform is
out of the transport position.
To reset the fault the emergency stop switch should be recy-
cled.
IF THE FAULT PERSISTS BRING THE PLATFORM TO THE GROUND POSITION,
SWITCH THE MACHINE OFF AND CONTACT A QUALIFIED SERVICE REPRESEN-
TATIVE TO INVESTIGATE THE FAULT.
Fault Response
ERROR RESPONSE
If basket level varies from the current setpoint by ± 5.5º for
more than 1.5 seconds when the platform is not in the trans-
port position, the following events will occur:
1. The platform dump valve will be disabled (level, rotate
and jib functions disabled).
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 platform is in
the transport position see below).
When the unit is in the transport position and driving and the
current setpoint varies by ± 5.5º for more than 8 seconds the
events 1,2,3 & 4 above will occur. (note function speeds will
operate normally). Cycling the EMS will clear the fault and
allow the operator to operate the machine as a new level
set-
point is taken.
VALVE DRIVER ERRORS
There are three possible level valve driver errors, short to bat-
tery, short to ground, and open circuit.
1. In the case of a short to ground or an open circuit , the
platform valve cannot be turned on and the following
will occur:
a. All interactions with platform leveling shall cease
b. The Electronic Leveling System Fault Lamp shall
flash (to indicate that the leveling function has been
lost).
c. The platform alarm will sound.
d. A system fault will be logged.
e. All function speeds (lift, swing, telescope and drive)
will be placed in creep mode (except when the plat-
form is in the transport position).
2. In the case of a short to battery on one of the platform
leveling valves, the valve cannot be turned off and the
following will occur:
a. The platform dump valve will be turned off to pre-
vent unintended tilting of the platform.
b. All interactions with platform leveling shall cease.
c. The Electronic Leveling System Fault Lamp shall
flash (to indicate that the leveling function has been
lost).
d. The platform alarm will sound.
e. A system fault will be logged.
f. All function speeds (lift, swing, telescope and drive)
will be placed in creep mode (except when the plat-
form is in the transport position)
3. In the case of a short to battery on the platform dump
valve , the valve cannot be turned off. The controllability
of the platform leveling function will be impaired and
the following will occur:
a. All interactions with platform leveling shall cease.
b. The Electronic Leveling System Fault Lamp shall
flash (to indicate that the leveling function has been
lost).
c. The platform alarm will sound.
d. A system fault will be logged.
e. All function speeds (lift, swing, telescope and drive)
will be placed in creep mode (except when the plat-
form is in the transport position).
Lift, swing, drive and telescope will continue to operate
In each of the cases above it shall be necessary to re-cycle the
EMS to clear the fault. Operable functions shall be in the creep
mode except while below elevation.