Definition of Mass flow controller

A mass flow controller (MFC) is a device used to measure and control the flow of gases. A mass flow controller is designed and calibrated to control a specific type of gas at a particular range of flow rates. The MFC can be given a setpoint from 0 to 100% of its full scale range but is typically operated in the 10 to 90% of full scale where the best accuracy is achieved. The device will then control the rate of flow to the given setpoint. MFCs can be either analog or digital, a digital flow controller is usually able to control more than one type of gas whereas an analog controller is limited to the gas for which it was calibrated.