JLG 680S, Service And Maintenance Manual

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SECTION 4 - BOOM & PLATFORM
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4.11 ELECTRONIC PLATFORM LEVELING
Description
Electronic platform leveling replaces the conventional hydraulic
method of platform leveling. The term “platform leveling” does
not refer to the system maintaining the platform at level (or 0°)
with respect to gravity, but instead refers to the controls auto-
matically maintaining the platform within several degrees of a
preset angle.
To control electronic platform leveling the platform is equipped
with a pair of tilt sensors, one primary and one secondary,
mounted to the non-rotating portion of the platform rotator,
level up and level down valves that are used to provide propor-
tional hydraulic flow for each directional function, and a control
module that interprets the sensor readings and actuates the lev-
eling valves.
PRIMARY AND SECONDARY TILT SENSOR INTERACTION
Two tilt sensors, mounted on each side of the platform support,
are used to measure the incline of the platform with respect to
gravity and control the automatic platform angle control func-
tion. The right one (as viewed from standing in the platform) is
used as the primary sensor and the left one as a secondary
backup sensor.
If a fault occurs with the primary sensor, control will revert to the
secondary sensor. (This is discussed in more detail in the error
response section.)
Because of the mounting orientation of the tilt sensors, the pri-
mary tilt sensor will output ascending voltage values with
increases in positive platform tilt angle. The backup or secondary
tilt sensor will output descending voltage values with increases
in positive platform angle.