You can use a majority of LabVIEW VIs and functions to describe a dynamic system model. However, you cannot place certain structures, such as the Case structure, While Loop, For Loop, or Event structure, directly on the simulation diagram. Instead, you can place these structures in a subVI or simulation subsystem, which you then place on the simulation diagram.
By default, the Simulation Module executes VIs, Express VIs, and XNodes as continuous functions. You can change this behavior by using the SubVI Node Setup dialog box. To launch this dialog box, right-click the object and select SubVI Node Setup from the shortcut menu. You can configure a VI to execute at only major time steps of the ODE solver, at both major and minor time steps of the ODE solver, as a discrete function, or at initialization of the simulation diagram.