Profiles Optimize »

The Profiles Optimize node facilitates the set up for dynamic optimization. This node is enabled when at least one variable is selected as Optimize in Control Profile grid.

Control Profile Period Definition

The first step in dynamic optimization with REX is to divide the time horizon into periods, up to a maximum of five. Within each period, you may choose the complexity of the control profile by specifying whether the profile is Constant, Linear or Quadratic. Once these two specifications are made, REX can then determine the optimum profile in each period to maximize the yield.
This grid is used to choose the number of periods and the type of control profile for each period. The Control Profile Period Definition is organized as below:

• The Period column displays all the periods. You may also add more periods here.
• The Period Start Point % column displays the start point of a given period, by using a cumulative percentage with respect to the total time horizon. These read-only values are automatically entered by REX and are the same value as those entered for the previous period's End Point %.
• The Period End Point % column displays the end point of a given period. Note that the end point value of the last period must be 100.
• The Profile column is used to select the type of profile for each period. Three different types may be chosen:
  
  • Constant
  • Linear
  • Quadratic

Adding a Period

Use the actions described below to add/delete a period

Profiles Derivatives Variables

This grid is visible when the Derivative Bounds toggle button is active. The columns in this grid are:

• The Variable column, that displays all the variables selected as Optimize in the Control Profiles node.
• The Specify Derivative Bounds column, where you can select the variables for which you would like to enforce derivative bounds. For example, if the Temperature is optimized, you may wish enforce bounds on the maximum heating and/or cooling rates, which are derivatives of the temperature.

Derivative Bounds

This toggle button allows you to enforce bounds on the derivatives of the variables that were chosen as Optimize in the Control Profiles node. This feature is only available when the Control Profiles toggle button is active and is useful to limit sharp changes in the optimized profile.
If the button is inactive, constraints on the derivatives are ignored. The Profiles Derivatives Variables grid and the Profile Derivatives Bounds node will will be hidden. However, the values are still stored, and may be recovered by enabling the derivative bounds again.

Add

This action allows you to add one extra period. A Dialog box is shown so you can select whether the new period will be constant, linear or quadratic.
When adding periods, all periods start and end point values are reset to default. You may define up to five(5) periods.

Delete

This action deletes the last period, and is enabled when there are two or more periods.
After execution, start and end point values for all the remaining periods are reset to default.

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