Reclaim Trigger Events

Unsuccessful claims of all crane bridges in an envelope are re-attempted when a reclaim trigger event occurs in that envelope. The following events are considered to be triggers for claim re-evaluations in the related envelope:

• The duration of a USE <crane> statement expires.

• You free a crane using the FREE statement.

• A crane completes a deposit (unless you specify the KEEP option).

• A crane completes a pickup and the crane is about to start moving to deliver.

• A crane downtime ends.

• You preempt a crane resource.

• A bridge arrives at its task destination (before elapsing pickup/deposit time).

• There are no moving task bridges left (for envelopes with 3 or more cranes only).

In the first six cases, a crane changes state from "immovable" to a finite move priority. The seventh case may change the "effective move priorities" of other cranes. ProModel requires the eighth case for envelopes with three or more bridges with overlapping operation zones: It ensures that two or more unsatisfied, opposing claims with the same move priority will resolve their conflict based on earlier task assignment time instead of locking up the crane system. Hence, all of the above cases create a potential to realize previously unsuccessful claims.

The reclaim trigger events for each envelope echo in the trace together with the triggering reason for model debugging purposes. The results of reclaim attempts for each crane resource and its effects on other crane resources in the same envelope are also displayed.