JLG 1500SJ Service Manual - Manual (Page 250)

SECTION 4 - BOOM & PLATFORM
4-4 – JLG Lift – 3121262
Drive/Steer – Boom Function Interlock
System (CE ONLY)
The Drive/Steer – Boom Function Interlock System uses
the Transport Position Sensing System to sense when the
boom is out of the transport position. All controls are
simultaneously functional when the booms are within the
transport position as on the standard machine. When the
boom is beyond the transport position, the control func-
tions are interlocked to prevent simultaneous operation of
any boom function with drive/steer. The first function set
to be operated in this mode, becomes the master function
set. In other words, while operating drive/steer functions
the boom functions are inoperable. Likewise, while operat-
ing boom functions drive/steer functions are inoperable.
Jib Stow System
The stowed length of the machine can be reduced to
enable transport on standard trailers by swinging the jib to
the right using the jib stow rotator. The control system will
prevent swinging the jib unless the axles are retracted, the
boom and jib are in the transport position (refer to Trans-
port Position Sensing System), and the jib stow override
button on the platform control panel is held in combina-
tion with the jib stow function switch. When the jib is
stowed, automatic platform leveling is disabled, the boom
is restricted to the transport position, and axle extension is
disabled. This system is functional only in the 500 lb (227
kg ANSI markets or 230 kg CE market) mode of the Dual
Capacity System. Jib telescope function will resume when
the jib is fully stowed along side the main boom.
Envelope Tracking System
The Envelope Tracking System uses the envelope control
sensors to enhance the control of the boom within the
working envelope. Due to the shape of the working enve-
lope, the maximum boom angle varies with telescope
length. To maintain unrestricted operation of the boom,
the lift down function is automatically introduced while
telescoping in only when the boom is on the rearward
edge of the envelope. This only occurs when telescoping
in along the rearward edge and is not used elsewhere
within the envelope or when telescoping out. Envelope
tracking is disabled with any envelope or moment viola-
tions or failures. The envelope tracking functionality and
be turned off using the manual position of the boom con-
trol select switch. Refer to Boom Control Select.
Moment Control System
The Moment Control System is the secondary means of
controlling the stability of the machine. This system uses a
load moment pin to attach the lift cylinder of the boom to
the turntable. This pin is instrumented with gauges allow-
ing the forces in the pin to be monitored. These forces are
used to compare the actual boom moment (force at a dis-
tance) to a predetermined allowable boom moment. In
controlling the boom moment, the position and load of the
boom is controlled. The moment control system will
detect moments larger than expected as well as those
smaller than expected. This effectively controls the for-
ward and rearward positions of the boom. The moment
control system varies the maximum allowable moment
based on ground slope. On level ground and with rated
load in the platform, the allowable moments establish a
working envelope slightly larger than the Envelope Con-
trol System’s envelope to minimize interaction of the sys-
tems. With increasing ground slopes and rated load in the
platform, the allowable moments may establish a working
envelope smaller than the Envelope Control System’s
envelope and may result in moment violations at the
extreme platform positions. Violations of the moment con-
trol systems allowable moment will result in reduced func-
tion speeds, BCS warning light illumination, restriction of
functions, and sounding of the platform alarm and the
flashing of the BCS light with attempts to operate
restricted functions. The restricted functions due to
moment system violations related to forward reach are
disallowing jib functions, lift down, telescope out, swing,
drive, and steer. The restricted functions due to moment
system violations related to backward reach are disallow-
ing jib functions, lift up, telescope in, swing, drive, and
steer. Recognized failures within this system will result in
control by the Envelope Control System, reduced function
speeds, BCS warning light illumination. The boom will be
restricted from leaving the transport position until the fail-
ure is resolved.