JLG 1250AJP Service Manual - Manual (Page 249)

SECTION 4 - BOOM & PLATFORM
3121171 – JLG Lift – 4-9
approached. The control system indicates to the operator
this automatic introduction of slow down by flashing the
creep light on the platform display panel. This feature
applies to both platform and ground controls, however, no
indication is made on the ground control panel.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.
4.13 DUAL CAPACITY SYSTEM
The Dual Capacity System is a multiple envelope control
system as opposed to a capacity indication system. The
control system changes the allowable working envelope
to match the capacity select mode to either the 500# (230
kg) mode or the 1000# (450 kg) mode. It then displays
the capacity mode on the platform and ground display
panel and controls the positions of the main boom within
the allowable envelope for that mode. This mode is select-
able by the operator with the dual capacity select switch
on the platform control panel.
The 500# (230 kg) mode has the largest envelope and
allows the use of the side swing jib. The 1000# (450 kg)
mode has a smaller envelope and requires the jib to be
fixed in the centered position.
The control system uses the envelope control sensors
(item16) in addition to the 4 limit switches and cams
mounted on the main base and fly booms to restrict the
main boom length between the main boom angles of
+55° and –45° for the 1000# envelope.
To select the 1000# (450 kg) mode the boom must
already be in the smaller 1000# (450 kg) envelope and
the jib must be centered (+/-10 degrees) verified to the
control system by the jib centered limit switch mounted on
the side swing rotator.
When the operator selects the 1000# (450 kg) mode and
these conditions are met, the capacity light changes from
500# (230 kg) to 1000# (450 kg), jib swing is disallowed,
and the envelope is changed accordingly.
When the operator selects the 1000# mode and these
conditions are not met, both capacity lights will flash, the
platform alarm will sound, and all functions except jib
swing will be disabled until the capacity select switch is
put back into the 500# (230 kg) position. Operation of jib
swing in this condition can be used to find the center posi-
tion of the jib as the jib swing function will stop when the
center position is reached.
When in the 1000# (450 kg) mode, attempts to telescope,
lift or lower the main boom into the restricted area will
cause that function to be prevented.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.
4.14 HYDRAULIC SYSTEM WARM UP
For optimal life and performance of the hydraulic system
in extremely cold temperatures, the control system moni-
tors the hydraulic system temperature and automatically
limits the function speeds of the high demand functions.
While the system is cold and in the warm up mode, the
tower lift, main lift, and main telescope functions are lim-
ited to creep speeds and is indicated to the operator by
flashing the creep light on the platform control panel.
Operating the machine while in the warm up mode will
generate sufficient heat to bring the hydraulic temperature
up to allowable temperatures and the warm up mode will
be automatically turned off. Although operating any func-
tion will generate heat, the tower lift function will warm the
hydraulic system temperature the fastest as this function
will operate tower lift, tower telescope, and main lift func-
tion automatically.
Functions being operated when the warm up mode turns
off will remain in the creep speed until the function is re-
initiated.
NOTE: For more detailed information concerning system
adjustment and operation, refer to Section 6 - JLG
Control System.
4.15 REDUCED PLATFORM HEIGHTS
The control system allows the maximum platform height of
the machine to be restricted to a selectable reduced
height to allow increased versatility in the rental market.
The selection of 125, 100, and 80 ft maximum platform
heights are available in the dealer mode - machine set up
menu on the analyzer. The reduced platform heights are
implemented by restricting the travel of the tower boom
up the tower path (see Section 4.7, Tower Path Control
System) while maintaining all other aspects of the enve-
lope control system (see Section 4.6, Envelope Control
System). The limits and functionality of the main boom are
unaffected by the selection.