JLG 1850SJ, Service And Maintenance Manual, Page: 166 / 712

SECTION 4 - BOOM & PLATFORM
4-4 3121619
Platform Load Sensing System
The Platform Load Sensing System consists of 4 load cells,
mounted between the platform and platform support, and a
dedicated electronic interface module (LSS) located below the
platform console. This system compares the capacity mode
(500# or 1000#) recognized by the dual capacity system to the
measured weight in the platform. When the capacity is
exceeded, or when there is a fault in the system, the platform
overload indicator will flash, the platform alarm will sound and
all platform controls (except auxiliary power) will be disabled.
The ground controls are unaffected.
Electronic Platform Leveling
The electronic platform leveling system uses two tilt sensors
(mounted on either side of the platform rotator), a control
valve (mounted to the platform support), a level cylinder, and
the platform control module (mounted in the platform control
box) to automatically measure and control the incline of the
platform with respect to gravity. While in the automatic posi-
tion of the boom control select platform leveling is active
while operating drive, telescope, main lift, jib lift or swing and
is not active while operating any other function (e.g. rotate, jib,
or steer). While in the manual position of the boom control
select platform leveling is active while operating main lift and
jib lift only. The system controls the platform angle relative to
gravity using a set point established during power-up (cycling
of the EMS) or at the conclusion of a manual platform level
override by the operator using the platform level override
switch from either the platform or the ground control. In other
words the operator can choose a platform incline other than
level with gravity and the system will maintain that incline
automatically. If a fault occurs in the platform leveling system
the following will occur:
• Automatic platform leveling will stop (except when there is
a fault in only one sensor)
• The platform level fault indicator will flash
• The platform alarm will sound
• All functions will default to creep speed if in platform mode
and the boom is out of the transport position
To reset the fault the emergency stop switch should be recy-
cled.
Boom Control Select
The boom control select switch is mounted on the platform
control panel and allows the operator the ability to select
between two different modes of boom control functionality:
automatic and manual. While in either mode, the envelope
control system and moment control system remains active.
When the boom control is selected to the automatic boom
control position, lift and telescope movements are coordi-
nated by the control system as described in the controlled arc,
controlled boom angle, and envelope tracking descriptions.
These systems will remain active to automatically assist the
operator in keeping the boom within the envelope boundar-
ies. When operating in the automatic mode, the following
functionality characteristics should be noted.
• While operating Lift Up, the boom may also telescope out
(controlled arc)
• While operating Lift Down, the boom may also telescope in
(controlled arc)
• While operating Swing or Drive, the boom may lift up or lift
down (controlled boom angle)
• While operating Telescope In, the boom may lift down
when at high boom angles and the creep light is flashing
(envelope tracking)
In addition, when the boom control is selected to the auto-
matic position, the automatic platform leveling feature is
active during lift, telescope, swing, and drive movements as
described in the electronic platform leveling system descrip-
tion.
When the boom control is selected to the manual position, lift
and telescope movements are controlled separately by the
operator effectively turning off the controlled arc, controlled
boom angle, and envelope tracking systems. Without these
systems being active, the control system will stop the move-
ments of the boom when the envelope boundaries are
reached and the functions that could violate the envelope will
be restricted. The platform alarm will sound and the BCS light
will flash with attempts to operate a restricted function. In
addition, when the boom control is selected to the manual
position, the automatic platform leveling feature is active only
during lift movements.