JLG 1250AJP Service Manual - Manual (Page 490)

SECTION 6 - JLG CONTROL SYSTEM
6-58 – JLG Lift – 3121171
2. After the pressing the ENTER key , the ana-
lyzer will display “CALIBRATING…”on the bottom
line and Control System will record left tower angle
3, right tower angle 3, and chassis tilt sensor values.
The Control System must see a change in the drive
orientation switch or “CAL FAILED” and “DRIVE
ORNT SW” will be displayed. If the change in right
sensor readings is more than 1.0 from the change
in left sensor readings, “CAL FAILED” and “TWR
ANGL FAILED” will be displayed. The control system
establishes the ground slope in relation to the boom
using the 4 tower boom angle sensor readings
before and after rotation. Ground Slope Left angle
sensor = (left 2-left 3)/2; Ground Slope Right angle
sensor = (right 2-right 3)/2. The Control system
establishes the low tower angle calibration point per
sensor by taking the difference between the angle 3
and the ground slope in the direction of the boom.
Low Tower Angle Calibration value = -3.8 +/-
Ground Slope. The chassis tilt calibration is calcu-
lated as in the chassis tilt calibration procedure. The
chassis tilt calibration will be established here and in
the separate chassis tilt procedure. If the chassis tilt
reads more than 1.75 the Control System will keep
the chassis tilt calibration data and the analyzer will
display “CAL FAILED” and “TILT CAL FAULT”.
Step 4 - Position 4
1. After completing the previous step, the analyzer will
read:
The Control System will disable all functions except
auto platform level and tower lift up.
Operate the Lift tower function.
2. Once the Tower Boom lifts such that the Tower
Boom Angle reads greater then 25 degrees, Tower
Lift Up will be suspended and the analyzer will dis-
play “CHECKING BOOM…”
3. Once “CHECKING BOOM…” is started the control
system will wait 2 seconds and then capture the
position of the Main Boom to Tower, Tower Cylinder
Angle and Tower Length. The control system will
then command the Main Lift, Tower Lift and Tower
Telescope PVG valves to 40%, engage the Main
Control and PVG enable valves and command the
Engine to 1800 RPM for 20 seconds. The control
system will monitor for the Main Lift angle increasing
by more then 0.2 deg, Tower Lift angle increasing by
more than 0.2 deg and the Tower Telescope length
increasing by more than 0.5" (1.3 cm). If one of
these conditions occur the test will abort and display
on the top line “CHECK FAILED:” and “MN LIFT
ENABLE”, “TWR LIFT ENABLE” or “TWR TELE
ENABLE” on the bottom line depending on which
section moved. After the 20 seconds has elapsed
the control system will command the engine back to
idle, shut off the commands to the PVG valves, dis-
engage the Main Control and PVG enable valves
and Turn On the Main Lift, Tower Lift and Tower Tele-
scope Enable valves and monitor the Main Lift angle
for decreasing movement of more than 0.2 deg,
Tower Lift angle for decreasing movement of more
than 0.2 deg and Tower Telescope length decreas-
ing movement of more than 0.5" (1.27 cm) for 60
seconds. If one of these conditions occur the test
will abort and display on the top line “CHECK
FAILED:” and “MAIN LIFT HOLD”, “TOWER LIFT
HOLD” or “TOWER TELE HOLD” on the bottom line
depending on which section moved. After the 60
seconds has elapsed the control system will leave