Add a Global Reduced Model Inputs node () under Global Definitions to declare global variables for use as controlling inputs to Reduced-Order Model nodes. You add it by right-clicking Global Definitions and choosing Global Reduced Model Inputs from the Reduced-Order Modeling submenu.

Specify a Control name and Expression for each required input. There are two possibilities: either enter the name of an existing model parameter, or select a new name. Entering the name of an existing model parameter will redefine that parameter as a reduced model input with the online expression linked from the parameter’s original definition in a Parameters node. In this case, the Expression column immediately displays the linked expression and is not editable. If you instead select a new name, you must also enter an online expression which will define the value of the input variable in all situations except during training of a reduced model (see Reduced-Order Model Inputs).