Patent ID: 6205409
Filing Date: 2001-03-20
Classification: G01F,G05D,Y10T

Abstract:
An apparatus for monitoring operation of a mass flow controller (MFC) comprising:a first interface circuit having a first input for receiving a particular setpoint signal conveyed to the MFC by a control system operably connected to the MFC, and for generating, on a first output of the first interface circuit, a first signal corresponding to the particular setpoint signal, said first interface circuit having a second input for receiving an actual valve control signal generated by the MFC in response to the particular setpoint signal, and generating, on a second output of the first interface circuit, a second signal corresponding to the actual valve control signal;a storage circuit for providing an expected valve control signal corresponding to the particular setpoint signal received by the MFC;a comparison circuit for comparing the second signal to the first signal to determine whether the actual valve control signal received from the MFC falls within a predetermined range of expected valve control signals corresponding to the particular setpoint signal conveyed to the MFC; anda status interface for conveying information related to whether the actual valve control signal received from the MFC is determined to fall within the predetermined range.