Page 454 - ExtendSim User Guide
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Mixing Flow and Items
Using the Interchange block to mix items with flow
☞ TheCreateblock’sabilitytoCreateitemsinfinitelyisspecificallyintendedforthistypeof situation. It provides an infinite supply of items that are available on demand, creating items whenever there is a capacity for flow.
Tank is separate from item
In this mode, the Interchange block's ability to handle flow is identical to the Tank block irre- spective of the presence of an item. That is, the Interchange can be set to have an initial amount of flow, its capacity can be set through the dialog or through a connector, and maximum inflow/outflow rates can be defined.
The only difference lies in the Interchange block's ability to pipe flow into and out of items. When the Interchange block is set to Tank is separate from item, the block can receive and hold flow that has been provided by its inflow connector or the arrival of an item and it can release flow through its outflow connector or through the exiting of an item.
☞ When the Interchange block is in this mode, an item carrying flow releases its entire load instantaneously upon arrival. However, depending on other settings in the block, the item can also take flow with it upon exiting. If this is the case, the Interchange block's flow level is dec- remented instantaneously when the item leaves. Furthermore, an item whose load of flow exceeds the block’s capacity will be blocked from entering the Interchange.
Bucket Elevator 1 model
The Bucket Elevator 1 model simulates a series of buckets (items) pulling flow out of a source (an Interchange block) located at a low elevation, transporting the water in a series of steps to an infinite sink located at a higher eleva- tion (another Interchange block), and then returning empty through a series of steps to the source. Both Inter- change blocks are set to Tank is separate from item. With this setting, both the source and the sink have the capacity to hold water even in the absence of an item.
This model is similar to a con-
tinuous loop of buckets draw-
ing water from a well,
emptying into a catch basin,
and returning to the well.
There are ten bucket/items and
each bucket has a capacity of
100 gallons; this is defined in the Resource Item block by the attribute Capacity. There are also ten slots in this “pseudo-conveyor” – each represented by an Activity block that can hold one item/bucket. The delay at each slot is 1/10 the sum of all the delays, as determined by the items’ Speed attribute.
Bucket Elevator 1 model
Discrete Rate

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