Abstract: Disclosed is a diagnostic system for measuring and monitoring selected operating parameters of a solenoid operated valve. The valve assembly, comprised of a valve body, a valve plug attached to a valve stem is actuated or operated by a solenoid. The valve assembly is provided with one or more sensors attached to or positioned adjacent to the valve assembly to measure and monitor selected operating parameters of the valve assembly and provide electrical output signals indicative of the measurements to a signal conditioning, processing and data collection apparatus used to receive and record the electrical output signals. The diagnostic system allows the user of the valve to measure and monitor the various electrical and mechanical activities of the valve during its operation while in service and to see if the valve is operating within its design parameters.