JLG 340AJ, Service And Maintenance Manual

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SECTION 6 - JLG CONTROL SYSTEM
6-44 – JLG Lift – 3121259
Testing & Evaluation
Refer to Troubleshooting if the Load Sensing System fails to
meet these guidelines.
1. Connect the JLG Analyzer.
2. Level the Platform. The platform should be approxi-
mately level for analysis, or the guidelines below will not
be applicable. Level the platform from Ground Control
(if necessary) to within ±5 degrees.
3. Observe the Empty Platform Weight. Proceed to the
DIAGNOSTICS, PLTLOAD sub-menu and observe the
measured platform load. All tools, debris, and customer-
installed devices shall be removed during evaluation.
Ideally, the PLTLOAD should be zero but can vary ±15lbs
(± 7kg). Further, the reading should be stable and
should not vary by more than ±2lbs (±1kg) (unless there
is heavy influence from wind or vibration).
4. Use the Technician’s Weight to Evaluate. The technician
should enter the platform and record the PLTLOAD read-
ing while standing in the center of the platform.
5. Confirm Control System Warnings and Interlocks. Using
the keyswitch, select Platform Mode and power-up.
Start the vehicle’s engine and ensure that all controls are
functional and the Load Sensing System’s Overload
Visual and Audible Warnings are not active. Simulate an
Overload by unplugging the Shear Beam Load Cell. The
Overload Visual Warning should flash, and the Audible
Warning (at Platform and Ground) should sound for 5
seconds On, and 2 seconds Off. With the engine run-
ning, all control should be prevented. Cycle the Platform
EMS to stop the engine and then power-up again. The
Overload Visual and Audible Warning should continue.
Confirm that controls are responsive when using the
Auxiliary Power Unit for emergency movement. Recon-
nect the Load Cell. The Overload Visual and Audible
Warnings should cease and normal control function
should return. Switch the vehicle’s keyswitch to Ground
Mode and repeat the above procedure. The Overload
Visual Warning at the Ground Controls should flash, and
the Audible Warning (at Platform and Ground) should
sound for 5 seconds On, 2 seconds Off. However, the
controls should remain functional when using the
engine and the Auxiliary Power Unit (if the Control Sys-
tem’s MACHINE SETUP, LOAD is set to “2=CUTOUT PLT”. If
set to “3=CUTOUT ALL”, then Ground Controls will be
prevented when using the engine as in the platform).
6. Confirm Control System Capacity Indication (optional
for vehicles with Dual Capacity Ratings). For vehicles
equipped with a Capacity Select switch on the Platform
Console Box, it is necessary to examine an additional
interface between the Load Sensing System and the
Control System. Using the keyswitch, select Platform
Mode and power-up. If necessary, put the boom in the
transport position (completely stowed) and center the
Jib Plus (if equipped). Place the Capacity Select switch in
the unrestricted position and ensure that the proper
indicator illuminates on the Platform Console Box. Plug
the JLG Analyzer into the Analyzer connection and pro-
ceed to the DIAGNOSTICS, SYSTEM submenu. Ensure
that the CAPACITY displays indicate OFF. Place the
Capacity Select switch in the unrestricted position (if so
equipped) and ensure that the proper indicator illumi-
nates on the Platform Console Box (but does not flash).
For vehicles with unrestricted capacity, ensure that the
unrestricted CAPACITY display indicates ON but the
restricted CAPACITY indicates OFF. For vehicles with
restricted capacity, ensure that the unrestricted CAPAC-
ITY display indicates OFF but the restricted CAPACITY
indicates ON.
7. Confirm Load Sensing System Performance with Cali-
brated Weights. Operate the vehicle from Ground Con-
trol and place the boom in the transport position (fully
stowed) for safety. Plug the JLG Analyzer into the control
system connection and proceed to the DIAGNOSTICS,
PLTLOAD display. Place 500lbs (230kg) in the platform
and ensure that PLTLOAD is with ±5% of the actual
weight. For Dual Capacity vehicles, do the same for the
alternate capacity (unrestricted or restricted).