Elliott Digger Derrick, Operation & Maintenance Manual, Page: 251 / 376

5
W450320A 09/12
PRESSURE SENSORS
There are two pressure sensors which measure pressure in the boom hoist cylinder. One sensor to
measure the rod-side pressure and one sensor to measure the piston-side pressure.
ANTI-TWO-BLOCK (ATB)
The ATB switch monitors the approach of the hookblock or overhaul ball to the boom head. The switch
is held in the normal position until the hookblock or overhaul ball raises a weight that is mounted around
the hoist rope. When the weight is raised it opens the switch. The resultant switch open signal is sent to
the computer via the reeling drum. This results in the ATB alarm operating and a function kick-out to
occur.
FUNCTION KICK-OUT
Electrically-operated hydraulic solenoids disconnect the control lever functions for boom hoist lower,
telescope out, and winch up when an overload or ATB alarm condition occurs.
OPERATOR PROGRAMMABLE ALARMS
These alarms, when properly set by the operator, define the working range. The operator can set the
minimum angle, maximum angle, maximum height, and maximum length.
These alarms are programmable for each job site and allow the operator to work in a defined area.
WORK AREA ALARM
This alarm permits the operator to define the operating zone by only two set points. The use of this
method results clearly defines the operating zone.
OUTRIGGER POSITION SENSING
This alarm alerts the operator, audibly and visually, when the selected outrigger position does not
match the detected outrigger position.
SWING SENSOR
This measures the angle of the boom relative to the chassis.