RATED CAPACITY LIMITER
OPERATOR MANUAL NBT60XL
7-2
Published 11-01-2020 Control # 710-00
RCL SYSTEM OVERVIEW
The Rated Capacity Limiter (RCL) is an operational aid that
warns the operator of an impending dangerous overload
condition that could result in death or injury to personnel and/
or damage to equipment and property.
The National Crane RCL system consists of an operator’s
console, anti-two-block switch, length sensor, angle sensor,
slew potentiometer, outrigger length sensors, rod and base
side lift cylinder pressure transducers, and if equipped, a
wind speed indicator. The RCL has the crane load charts
loaded into the RCL module. The load charts are displayed
on the screen as needed. When a load is lifted, the RCL
compares the actual conditions with the load chart. If an
overload condition is sensed, audible and visual warnings
are generated and the crane function controls that worsen
the overload condition (boom down, telescope out, and hoist
up (main and auxiliary)) are disabled.
Components:
•
RCL display on the operator console.
•
RCL control module (front console).
•
Length/angle sensor with cable reel mounted on side of
boom.
•
Lift cylinder pressure transducers integral to lift cylinder
hold valve.
•
Anti-two-block switch (ATB) on the boom nose.
•
Outrigger length sensors (on each outrigger beam).
•
Slew sensor internal to the electric swivel.
•
If equipped, wind speed indicator: an anemometer on
the boom or jib and a wireless gateway router in the
crane cab.
9677
FIGURE 7-1
2
3
1
WARNING
The RCL is not a substitute for good operator judgment,
experience, and safe operating procedures. The
responsibility for safe crane operation remains with the
operator.
The RCL is not a scale and should not be relied upon
solely to accurately weigh loads.
!
Fo
r
Reference
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