Abstract: A volumetric flow control apparatus and method for measuring and controlling the volumetric flow rate and flow volume of a fluid. The apparatus comprises a reciprocating diaphragm meter having a diaphragm mounted for reciprocating movement and a diaphragm position indicator assembly for monitoring the position of the diaphragm as it reciprocates. As a fluid under pressure passes through the reciprocating diaphragm meter the diaphragm reciprocates through at least one meter cycle during which the meter passes a fixed volume of fluid per meter cycle. A timer responsive to the diaphragm position indicator is provided to measure the elapsed time for the meter diaphragm to reciprocate through at least one meter cycle. A processor calculates the volume flow rate of the fluid passing through the reciprocating diaphragm meter by dividing the fixed volume of fluid passed by the meter in a meter cycle by the elapsed time measured during the meter cycle.