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Figure 6: Settings for speed limiting
In this example the high speed function would drop out at 9000Kg
4.1.3 Setting up for slack rope detection
Connect one of the relays in series with the control signal to the down contactor and set the set
point to 0Kg
Figure 7: Settings for slack rope detection
Nb for slack rope detection to work reliably the unit must see at least a 5% change in load when the
rope goes slack. For a 10t crane this means the hook block, hook and any lifting fixture must weigh a
MINIMUM of 500Kg. If you try to implement slack rope detection with a normal light duty hook
block then you can be 100% sure that you will end up with an angry customer who can’t lower the
hook. In practice, slack rope detection requires additional load in the form of a lifting jig, or dead
weight added to the crane.
When implementing slack rope detection the zero load for the MaxOut or Liftlog should always be
taken with the hook at the top limit. If you don’t do this then the Liflog or MaxOut will see the load
decrease as the hook is raised because the rope is being wound onto the drum. If this causes the
load to drop below the set point then the operator will be unable to lower the hook.
