Terex Genie Z-135/70, Service And Repair Manual

Page: 216 / 244

Service and Repair Manual October 2018
Limit Switches and Angle Sensors
202 Z®-135 /70 Part No. 1268557GT
Types of Limit Switches
There are two types of limit switches, found in
various locations throughout the machine:
mechanical-type
operational/safety switches and
rotation or angle sensors. As in aircraft, which
features redundant safety systems, each
mechanical operational switch is backed up with a
separate, independently functioning safety switch.
The mechanical-type operational or safety
switches are used to sense a positive displacement
or movement of the limit switch actuator, or arm, as
the machine moves through its range of operational
functions. The
rotation or angle sensors utilize Hall
Effect technology and must be calibrated when
replaced. Included in this group are envelope limit
switches which sense the extended length and
angle of the booms and rotational position of the
turntable.
For example, when the secondary boom is fully
raised and the operational sensor is activated, it
tells the ECM at the ground controls to start
extending the secondary boom.
Another example is the drive enable limit switch,
which disables the drive function anytime the boom
is rotated past the rear tires, indicated by the 'circle'
end of the drive chassis.In some cases, the engine
will be stopped if safety parameters are exceeded.
Numbering Legend
LS FA 1 L O
LS Limit
Switch
FA Front
Axle
Circuit
Number
L Load
moment
O Operational
LT Stringpot RA Rear
Axle
A Angle S Safety
RS Rotary
Sensor
LF Left Front D Down
LR Left Rear E Extend
RF Right
Front R Retract
RR
Right
Rear
J Jib Boom
P Boom
T Turntable
Limit Switch Numbering
LSP1RO Primary boom length retracted
LSP1EO Primary boom length fully extended
LSS1RO Secondary boom fully retracted
LSS1RS Secondary boom fully retracted, safety
LSJ1RO Jib boom length fully retracted
LST1O Drive enable, left direction
LST2O Drive enable, right direction
LST1S Drive enable safety, retracted axles
LSFA1ES Front axle fully retracted
LSRA1ES Rear axle fully retracted