[G-LIFE Self-Diagnosis Function]Offers more intelligent gas panels

With conventional MFCs, it is difficult to recognize changes in the gas flow rate resulting from the aging of the flow rate sensor. Criterion modules have a self diagnostic function named “G-LIFE” for Gas Law check of the Integrated Flow Equation. G-Life is activated when, at the end of a flow run, the MFC is given a 0% command and the upstream Piezo valve closes. At this time the gas in the volume between the closed valve seat and the flow restrictor bleeds out. The mass that leaves this volume can be calculated two separate and unique ways. The first method is to integrate the calculated flow from the restrictor equations. The second method is to use the Ideal Gas Law, knowing the gas temperature and starting and stopping pressure of the volume. Since both methods are acting on the same mass exiting the same volume, the two results can be compared over time detecting component or sensor issues. This self diagnostic function makes it possible for systematic maintenance to be conducted and accidental failure of process gas control to be prevented. These mass flow modules and G-Life diagnostics are a clear way to practice Advanced Equipment Control (AEC) technology.


more intelligent gas panels
  • Closes the valve to decrease the flow rate downstream of the valve.(1)
  • When the upper limit of the set flow rate is reached, reads the P1(a) pressure and starts integration of the mass flow rate.(2)(3)
  • When the lower limit of the set flow rate is reached, reads the P1(b) pressure and terminates integration of the mass flow rate.(2)(3)
  • Calculates the internal volume between the valve and flow restrictor from the pressure change P (P = a-b) and the integral of the mass flow rate using the equation of state for the gas and the equation for the restrictor.(1)(2)
  • Makes a judgment by comparing the calculated internal volume with the stored initial volume.



More intelligent gas panels