The element <functionalItemRef> contains a reference to the functional item’s CIR data module.A functional item can be used to uniquely identify an item that performs a function, in a system that is part of a Product.For example a functional item can be the third pump in a hydraulic system of a Product. Depending on the Product instance, this functional item can be mechanical or electrical, and so, can perform the function of a hydraulic pump.The functional item is also known as the reference designator.