JLG LSS Verticals Operator Manual - Manual (Page 9)

SECTION 2 - SERVICE PROCEDURES - LOAD SENSING SYSTEM
3124289 – JLG Lift – 2-1
SECTION 2. SERVICE PROCEDURES - LOAD SENSING SYSTEM
2.1 LOAD SENSING SYSTEM (LSS)
DESCRIPTION
The LSS system for Vertical Mast model machines con-
sists of a floating platform mount weldment (rails)
attached to the sides of the mast header section, transfer-
ring the platform load to a load bearing crossmember. The
platform mount load bearing crossmember is supported
by coil springs mounted between the platform crossmem-
ber and a crossmember attached to the mast header sec-
tion. Also attached to the platform mount weldment (rails)
is an adjustable actuator. The actuator, when adjusted
properly, trips the LSS limit switch mounted on the mast
crossmember when the platform is overloaded.
While the mechanical portion of the LSS system operates
the same for both the manually propelled and drivable
vertical lifts, the limit switch circuit (electrical) is monitored
differently as described following.
Manually Propelled Vertical Lift - Overload
Detection
(See Figure 2-1.)
The limit switch circuit on the manually propelled lifts is
monitored by an LSS Timing Module which disables the
platform lift up/lift down function, sounds an audible warn-
ing alarm and activates a flashing warning lamp when a
platform overload condition is detected. The LSS Timing
Module is mounted behind the LSS Indicator Panel
located behind the platform railing.
Drivable Vertical Lift - Overload Detection
(See Figure 2-1., Figure 2-2. and Figure 2-3.)
The limit switch circuit on the drivable lift is monitored by
the Ground Control Module (GCM) which controls all
machine functions and is mounted inside the machine’s
rear covers. Like the LSS Timing Module on the manually
propelled lifts, on overload detection the GCM on the driv-
able lift disables the platform lift up/lift down function, in
addition the drive function is also disabled. Indicators of
an overload condition are; an audible warning alarm;
flashing warning lamp; 9 LEDs flash on the platform con-
trol console and GCM LCD screen will flash "Platform
Overload". On the drivable lift, the audible warning alarm
and flashing warning lamp are located on the machine’s
left rear cover. (See Figure 2-2.)
On initial LSS installation or GCM replacement, the GCM
must be programmed to detect the LSS system in order to
function properly. See Section 2.5, "Ground Control Mod-
ule" in this manual for instructions on GCM - LSS detec-
tion programming.
Figure 2-1. Load Sensing System - Components.
1. LSS Timing Module (a) 7. Crossmember Stops
2. LSS Indicator Panel (a) 8. LSS Overload Actuator
3. LSS Warning Lamp (b) 9. LSS Limit Switch
4. LSS Warning Alarm (b) 10. Mast Header
5. Platform Mount (c)
11. LSS Arm Linkage
6. Coil Spring Assemblies
Note: (a) Manually propelled lifts only.
(b) Relocated on drivable lifts (See Figure 2-2.)
(c) Shown cut-away for illustrative purposes only.
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