MicroGuard 511 Retrofit
1
W450512 03/08
Introduction
The MicroGuard 511 Retrofit Rated Capacity Indicator System (hereinafter referred to as the
“system”) is intended to aid the crane operator by continuously monitoring the load and warning of
an approach to an overload or two-block condition. Crane functions are monitored by means of high
accuracy sensors. The system continuously compares the load suspended below the boom head with
the crane capacity chart stored in the computer memory. At approach to overload, the system warns
by means of audible and visual alarms. The system can be configured to cause function kickout by
sending a signal to function disconnect solenoids.
System Components
MicroGuard Display Console
•
Computer Unit
•
Pressure Transducers
•
Extension Reel with length and angle sensors
•
Anti Two-Block (ATB) switches
•
Cables
•
Extension Sensor
The extension sensor provides an increasing voltage proportional to the extension of the boom. A
cable attached to the boom head provides a low current electrical path for the ATB signal.
Pressure Transducers
Two pressure transducers measure the pressure in the boom hoist cylinder. The resultant Total
Moment signal is processed to provide a continuous display of the load suspended below the point of
lift.
Anti Two Block (ATB)
A 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 causes the switch to operate. The resultant signal is
sent to the computer via the extension reel causing the ATB alarm to operate and function kick-out to
occur.
Display
The operator is provided with a continuous display of:
Rated Load
•
Actual Load
•
Bar Graph showing Percentage of Rated Load
•
Radius of the Load
•
Boom Angle
•
Main Boom Length
•
Working Area
•
Crane Configuration
•
On-screen messages provide the operator with visual warnings of conditions that occur during
operation of the system.
