Enter and view data for smart constraints

The following procedure describes how to enter and view data for smart constraints:

1. Double-click a constraint object.

   

   The detail dialog for the constraint opens.

2. In the Constraint frame, specify a mathematical expression.

   The mathematical expression is almost always of the form A – B, which must be zero for the constraint to be met. Forcing the difference of two values to be zero is a way to ensure their equality.

   You can choose any field or combination of fields from an object in your model to serve as A and as B. The way in which you specify equations for use is the same as when you use the Equation Editor to enter equations into a stream or tank object, but note you will, in this case, normally use two objects’ reconciled flows or volumes as variables in the constraint.

   When doing component balancing, multiply the reconciled flows r volumes of two objects by component ratios and subtract one from the other to force equality.

3. Select .

   The Equation Editor opens.

   

General information

• Constraint Name: Same as for balance objects.

• Description: Same as for balance objects.

Detail info

• Show Information: Same as for balance objects. The information is the imbalance by constraint, similar to the other balance objects. If the constraint is satisfied, the reconciled imbalance of the constraint will be zero.

• Use Constraint in Reconciliation: Selects whether the constraint is obeyed in running data reconciliation. If you check this checkbox then the constraint serves as an additional constraint in data reconciliation as long as constraint usage is globally enabled. Constraint usage is globally enabled or disabled with the Run Reconciliation with additional Linear Constraints checkbox on the DR Solver tab of the Tool>Option dialog.

• Constraint Balance Type: Select the balance type for which the constraint is reconciled. The default is the primary balance type on the Eng. Unit tab of the Option dialog, as invoked by the Tool > Option menu item.