Page 27 - Continuous Process Modeling Quick Start Guide

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Tutorial 23
Blocks used for the simple Reservoir model
With these settings, the model will run for a simulated time of 36 months.
Save the model
Choose File > Save Model As and name the file My Reservoir Model.
☞ Models with changes that haven’t been saved have an asterisk (*) at the end of their name in the title bar. Each time you save a model, ExtendSim creates a backup, ModelName.bak, of your previously saved model. To recover using a backup file, rename the file to Model- Name.mox.
Blocks used for the simple Reservoir model
The following table lists the five blocks used in the model.
Name (Label) Lookup Table
Random Number
Math
Holding Tank
Line Chart
Library Value
Value
Value
Value
Chart
Block Function
Acts as a lookup table. You can choose to set it to output data based on the current time or based on the value it receives at its input.
Generates random integers or real numbers based on the selected distribution.
Performs mathematical func- tions. The same Math block can be used for a wide variety of purposes by selecting the desired function from a popup box in its dialog.
Accumulates the total of the input values. It also allows you to request an amount to be removed and outputs that requested amount, if available.
Displays graphs and tables of data input from continuous blocks.
Purpose in Reservoir Model
Represents rainfall entering the reservoir each month. The amount of rainfall is based on historical averages and varies with the month.
Generates random values that correspond to the changing flow of the stream. In this model, the stream increases the reservoir level between 0 and 1 inch of water per month.
Adds the amounts from the two different water sources and transfers them to the Res- ervoir.
Accumulates water from its two sources. In this model, the tank has an infinite capacity and nothing is removed.
Shows the amount of input from the two sources and the level of water in the reservoir as it is affected by the amount of water entering it.
There is nothing fundamentally different about the structure of these different blocks. Any block may create, modify, or present information, and many blocks perform more than one of these functions. You can, of course, have multiple instances of the same block within a model.
Placing and connecting blocks on the model worksheet
Methods for placing blocks in a model
There are two main methods for placing and connecting blocks in a model:
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