Page 432 - ExtendSim User Guide
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406 Delaying Flow
Controlling a Valve’s maximum rate
Quantity Goal model
This model uses a Pulse block (Value library) to periodically start a new quantity goal. At the start of the simulation run and every 60 minutes afterwards, the Pulse block sends a True value (a number  0.5) to the Production Gate valve’s start connector, starting a new goal.
The Valve’s maximum rate is 20 gallons/minute and the
simulation runs for 480 minutes. The control for the
movement of flow through the block is provided by its
Flow Control tab. The desired quantity of flow, 500 gal-
lons, is entered in the dialog. While the goal is On, flow
passes through the Valve at a maximum rate of 20 gal-
lons/minute. After 500 gallons, the goal goes Off, the
flow is stopped, and the effective rate goes to 0. As the
simulation runs, a plotter displays the Valve’s effective rate, the quantity of the goal and the times when it has been reached, and the number of each new goal.
Settings in the Flow Control tab cause the Valve to Start a new goal when “start” connector value = 1. The goal-starting options (seen at right) can also be set to start a new goal when the block receives a message at its G (goal) input connector or when the previous goal fin- ishes.
Quantity Goal model
Options for starting a new goal
You could have avoided building the Quantity Goal model by instead mentally calculating the effect of the goal on the flow. The rate interactions and results determined by the next model would not be so easy to compute.
Changeover Quantity Goal model
The Changeover Quantity Goal model involves a more complex system than the Quantity Goal model from above. This model, based on the stage of the Yogurt Production model that is dis- cussed in “Add maintenance” on page 338, shows how a quantity goal in a Valve can be used to control a sequence of production changeovers. The top part of the model is composed of
Discrete Rate

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