Additional function

The additional function is one of the three types of functions (alongside basic and auxiliary) that can be performed by components of an engineeiring system that is a device.

As a function directed at a supersystem component, it ranks higher (usually 2 points) than functions directed at system components but not as high as the basic function performed on a target component. This is because the ranking approach assumes that the main emphasis is placed on interactions between the system and the components of its supersystem.