Page 377 - ExtendSim User Guide
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Creating Flow 351
In the Yogurt Production model from the Discrete Rate tutorial, the Interchange blocks were set to Tank only exists when item is in it and Initial contents (on item arrival): 0.
Initialization of contents when “Tank is separate from item”
To set the initial contents for the Interchange block when this behavior has been selected, leave the Initial contents field set to the default infinite amount or enter a number.
Interchange initial contents, alternate behavior
With this behavior, arriving and departing items can cause contents to be contributed to or removed from the tank, depending on choices set in the block’s dialog.
Convey Flow initialization
The initial contents for the
Convey Flow block are set
in its Initialize tab. The
table allows you to custom-
ize a number of segments
for the conveyor, each with
its own initial contents. Each row in the table represents an individual segment of the conveyor possessing a uniform density that differs from the adjacent segments.
The Initialize tab has a Show Example button that places example settings in the table. These are helpful for understanding how to make the entries you want; they can also be used as a starting point for entries. Shown above is the example setting for a 100 foot long accumulat- ing-density conveyor that transports containers. The table indicates that the block would have an initial density of 10 containers per foot for the segment from 75 to 100 feet (a total of 250 containers) and 5 containers per foot for the segment from 25 to 50 feet (a total of 125 contain- ers).
☞ In this example, the sections between 0 and 25 feet and between 50 and 75 feet do not hold any product.
As the simulation runs, the level of flow in the residence blocks (Convey Flow, Interchange, and Tank) will vary over time.
You might want an indication when a block’s flow level is within a certain range of values. This is common when monitoring a block to determine if its contents are approaching or have reached one or more important benchmarks. For instance, some emergency procedures might need to take place if a Tank’s level reaches the “high” range; they can be discontinued when the contents return to a “normal” range.
For residence blocks, indicators are a method of reporting what category or range the current level of flow falls into. With this feature, each range is assigned a name, a lower limit, and an upper limit. When the level of flow reaches a value that falls within a different range, the block reports the change on its I (indicator) value output connector and alerts any connected blocks to the change in status.
☞ While the Tank and Interchange blocks report information about the current level of flow from their I (indicator) connectors, the Convey Flow block reports how far (the accumulation length) the accumulation point is from the end of the conveyor. (When the amount of product ready to leave exceeds the amount that can be received downstream, flow begins to accumulate
Example initial contents for Convey Flow block
Discrete Rate

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