Drop-off

The Agent Drop-off enables agents which are carrying items to release one or more of the items. Agent Drop-off Objects can be classified as “Logical with Capacity”, as they can hold items, and no time passes when they process items.

Items leave the Agent Drop-off independently to the agent. Agents pick up items using the Agent Pick-up object. The Agent Drop-off can be used when modelling situations where items move or are supplied in groups or batches. An agent carrying items can enter the Agent Drop-off, drop off some or all of the items being carried and then immediately leave the Agent Drop-off. The items leave the Agent Drop-off if they are not blocked. An item needs an outgoing path before it can be delivered to the Agent Drop-off.

Agent Drop-off States

Empty

The Drop-off Object is empty. An agent carrying items may enter and restock the Drop-off Object. The agent leaves immediately after.

Busy

The Drop-off Object contains some items. These will move out of it as soon as possible.

Full

The Drop-off Object has been stocked to its capacity. Agents cannot enter until some capacity is released (by items leaving)

Blocked

The agent is being blocked from leaving the Drop-off Object. A queue or dispatcher should be added after the tray to avoid this state occurring, because while the Agent is blocked, no Items can leave the Drop-off Object.

Capacity

Sets the maximum number of items the Agent Drop-off can hold at one time. Agent Drop-off capacities may be set by attributes. Selecting Capacity in the Agent Drop-off Object Menu brings up an Attribute selection dialog.

Max Qty. Dropped

This is a "per delivery" limit on the number of items an agent can drop into the Drop-off Object at one time. The default value is <no limit>. This indicates that no limit is set, and an entering agent will drop all qualifying items it is carrying in to the Agent Drop-off, (up to the capacity limit). When you select "Maximum Qty dropped", you are prompted to select an Attribute " for it. If you use a Constant Attribute to set the per-delivery maximum value, then every agent visiting the Agent Drop-off must comply with this per-delivery maximum value, and it will not vary during the course of a model run.

To reset the <no limit> value for the Agent Drop-off, select the Constant Option in the Attribute Selection Dialog, and type in "-1". If you use another type of Attribute to set the per-delivery maximum value, then every time that Attribute is changed during the course of a model run, the per-delivery maximum value will change also.

If you use an Item Attribute to set the per-delivery maximum value, then every time an agent goes to enter the Agent Drop-off, the Attribute is read by the Agent Drop-off and the per-delivery maximum value will be set to that value. Every agent that will use this Agent Drop-off must carry the Item Attribute.

Drop Item Flag

This is a control property that is set on to items being carried by an Agent. The Attribute Selection Dialog can be used to assign an Attribute. If for an incoming item this attribute is set to a value greater than zero, the item can be dropped (providing that there is an outgoing path for that item class). The "drop item flag" feature can be used at a given Drop-off Object even if some item classes dont have the "drop" attribute defined. As long as there isn't an outgoing flow for this class, an error wont be produced.

Refer to Editing Object Properties for information about editing properties common to all objects.