A peristaltic pump is able to deliver accurate volumes over the life of a
pump set that is operated on by the pump to drive the flow of fluid. The
pump delivers fluid in small volumes or aliquots. In order to deliver
fluid at any particular selected flow rate, the pump determines how often
the rotor will rotate. The pump is able to calculate aliquot volume based
on selected flow rate, but also on a factor that compensates for changes
in the dimensions of the pump set over its life.