5 • THE ADVANCED

5 • THE ADVANCED TRANSFER PANEL Allocate module DESCRIPTION The Allocate module assigns a transporter to an entity without moving it to the entity’s station location. The entity then has control of the transporter to either move it to a particular location or to halt it for a breakdown or failure. A particular transporter unit may be allocated to the entity or a selection rule may be used to determine which of the transporters will be assigned to the entity. TYPICAL USES • A mechanic allocates a forklift for scheduled maintenance • Allocate a taxi to pick up waiting passengers PROMPTS Prompt Name Transporter Name Selection Rule Save Attribute Unit Number Priority Entity Location Description Unique name of the module that will be displayed in the flowchart. Name of the transporter to allocate. Rule for determining which of the transporters to allocate to the entity. The selection rule has the following options: Cyclical, Random, Preferred Order, Specific Member, Largest Distance, and Smallest Distance. The attribute name that will store the unit number of the selected transporter. Determines the specific transporter in the transporter set to allocate to the entity. It is only visible if selection rule is Specific Member. Priority value of the entity waiting at this module for the transporter specified if one or more entities are waiting for the same transporter anywhere in the model. This field is used to determine the transporter closest to or farthest from the requesting entity when using the Largest Distance or Smallest Distance transporter selection rules. For free-path transporters, the entity location must be specified as a station. For guided transporters, the entity location may be specified as a station, intersection, or network link. 93

GETTING STARTED WITH ARENA Prompt Queue Type Queue Name Queue Set Name Set Index Attribute Name Expression Description Type of queue used to hold the entities while waiting to allocate the transporter, either an individual Queue, a queue Set, an Internal queue, or an Attribute or Expression that evaluate to the queue name. Name of the individual queue. Name of the queue set that contains the queue being referenced. The index into the queue set. Note that this is the index into the set and not the name of the queue in the set. For example, the only valid entries for a queue set containing three members is an expression that evaluates to 1, 2, or 3. The attribute name that will be evaluated to the queue name. The expression that will be evaluated to the queue name. Free module DESCRIPTION The Free module releases the entity’s most recently allocated transporter unit. If another entity is waiting in a queue to request or allocate the transporter, the transporter will be given to that entity. If there are no waiting entities at the time the transporter unit is freed, the transporter will wait idle at the freeing entity’s station location, unless otherwise specified in the Transporter module. TYPICAL USES • A part awaiting a shipping truck frees its forklift • An airport transfer cart completes its trip PROMPTS Prompt Name Transporter Name Unit Number Description Unique name of the module that will be displayed in the flowchart. Name of the transporter to free. A blank value assumes the most recently allocated or requested transporter. Determines which of the transporter units in the transporter set to free. 94