A system and method for accurately measuring supply gas consumed by a particular process control component within a process control system is disclosed. Enhanced measurement accuracy is derived from measuring the consumption of the process control component in a normal operating mode of the process control system. The amount of fluid expended by one process control component is separated by a fluid control system from the amount of supply gas expended in actuating other process control components. The amount of fluid expended by each component may be determined by measuring a decrease in a fluid within a vessel having a known quantity that independently supplies supply gas to each component during its operation.