Introduction to Variant Controls

The components of a Simulink^® model that contain variants are activated or deactivated based on the variant choice that you select.

Each variant choice in your model is associated with a variant control. Variant controls determine which variant choice is active. By changing the value of a variant control, you can switch the active variant choice. While each variant choice is associated with a variant control, only one variant control can evaluate to true. When a variant control evaluates to true, Simulink activates the variant choice that corresponds to that variant control.

Suppose you want to simulate a model that represents a vehicle with three possible engine configurations: 1-cylinder gas, 4-cylinder gas, and 8-cylinder gas. In this scenario, the value of throttle is an input to the engine that differs for different configurations. You could implement each engine configuration as a separate subsystem inside the Variant Subsystem block named Engine and then switch between the subsystems based on the value of EngineType. Similarly, you could use a variant parameter kv to store multiple values of throttle and then switch between the values based on the value of nc. For example, if the value of EngineType is 1 and the value of nc is 2, a throttle value of 20 is provided as an input to the Engine_2_cyl_petrol subsystem during simulation.

In this example:

• Structural variations are controlled by using the variant controls EngineType == 1, EngineType == 2, and EngineType == 3 in the Variant Subsystem block named Engine. For more information on how to control structural variations, see Variant Control Modes in Variant Blocks.

• Value variations are controlled by using the variant controls nc == 1 and nc == 2 in the variant parameter kv. For more information on how to control value variations, see Variant Control Mode in Variant Parameters.