Multivariable Controller - Options Window
Number of Iterations
The default value for the number of Multivariable Controller iterations is calculated by PRO/II as 18 plus the number of control variables. You can change the maximum number of iterations to some other value.
Scaled Variable Parameters
For all scaled parameters in the Multivariable Controller, the same initial value, step size, and tolerance is used. You may enter values other than the default values on this window. The default initial value is 100.0, the default value for the step size is 10.0, and the default error tolerance is 0.00001.
By default, if any control variable reaches its minimum or maximum limit, the simulation will stop. However, you may request that the calculations continue by checking the box.
Next Unit Calculated
Usually, the next unit operation calculated after the control variable is changed should be the first unit operation in the calculation sequence that is affected by the change in any control variable. By default, PRO/II will determine the next unit operation to calculate, but you may wish to give this information directly. See Problem Specific Calculation Sequence for more details.
When the MVC is varying multiple parameters and all are related to thermodynamic parameters, the user needs to enter the RETURN UNIT because PRO/II software cannot determine it.
Continue Calculations
When a variable value exceeds the limits defined, or the calculated values for the specifications are not met, by default, Fail Unit and Continue Calculations if Limits are Reached option is selected. It allows the MVC to use the best cycle as a solution and to continue the calculations. This could be useful in the case where the MVC fails to converge, which may preclude PRO/II in a few cases from finding an optimized solution along an infeasible solution path.
You can change the default option to any of the following if required:
Fail Unit and Stop Calculations if Limits are Reached
Accept as Solved if Limits are Reached
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