You are here: Building the Model: Advanced Elements > Material Handling Systems > Crane Systems > Handling Zone Claims In Multi-Crane Envelopes
If a crane is in one of the following states, it will be referred to as "immovable at a node." No other crane will be able to push this crane away, regardless of its priority.
• Picking up or depositing an entity.
• Being used at a location.
• Having a downtime, off-shift time, or break time.
Extended Movement Zone The net zone that it needs to traverse ± bridge separation distance (± depending on the direction that it will go).
Before starting to move, any <crane A> attempts to claim its extended movement zone (zone A) for the entire movement duration.
ProModel can reject the claim attempt of crane A for zone A for several reasons:
• If there are immovable cranes in zone A
• If there are any cranes in zone A with move priorities greater than or equal to1 the move priority of crane A, if they are going in the opposite direction, or they are going in the same direction with conflicting destinations.2
1. Special case treatment not ">=" but strictly ">" if all of the following conditions hold: (1) if the bridge that A is trying to oppose is stationary, (2) unless crane A is trying to move just to park (if A has a task or if it is trying to move out of the way of another bridge), (3) if the one A is trying to push is idle or its bridge was blocked before reaching its destination.
2. Destination Conflict Test: If sign (B' - A' - sign(existing claim)*(bridge_separation)) = sign (existing claim) then not conflicting.