Filling from an Entity

A typical tank modeling situation is the arrival of an entity (e.g., a tanker or other vehicle) to deliver its contents to a tank. To model this situation, define an arrival or routing for the entity, causing it to enter the location where it will make its delivery. In the entity processing logic at the delivery location, call the Tank_Fill subroutine. By calling rather than activating the subroutine, you will detain the delivering entity until Tank_Fill executes. Note that the material does NOT route from the delivery location to the tank. Instead, the Tank_Fill subroutine simply fills the tank with a specified quantity while the entity waits. Unless the quantity is a constant amount, it is usually a good idea to use an entity attribute to store this quantity value. After filling the contents into the tank, the entity is free to continue processing.

To illustrate how an entity might transfer its contents to a tank, suppose an entity, Tanker, arrives at a location, Delivery, carrying a quantity of gallons stored in an entity attribute called Tanker_Qty. The tanker discharges its contents into a tank, ReceivingTank, at a rate of 200 gallons per minute. Once the ReceivingTank becomes full, the level must drop to 1000 gallons before filling resumes. Since the entity is tied up while it discharges into the tank, use the following statement in the processing logic for Tanker at Delivery to define the logic used to fill the tank:

Fill the tank

Tank_Fill (ReceivingTank, Tanker_Qty, 200, 1000)

The above statement causes each arriving tanker to wait until the quantity stored in its Tanker_Qty attribute adds to the ReceivingTank. Once the tanker delivers this quantity, it is free to execute the routing defined for it at the Delivery location.