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Process gas distribution system and method with automatic transducer zero calibration

  • US 5,657,254 A
  • Filed: 04/15/1996
  • Issued: 08/12/1997
  • Est. Priority Date: 08/31/1990
  • Status: Expired due to Term
First Claim
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1. In or for a process gas distribution control unit which handles hazardous gases, said control unit having at least one gas pressure measurement transducer for measuring the pressure of gas handled by said control unit and outputting a measured output correlated to the pressure wherein there is an ideal output for each value of pressure,a system for correcting the measured output to approximate the ideal output at corresponding values of pressure, comprising:

  • means for subjecting said transducer to a known value of pressure to cause said transducer to output a measured output, there being a known ideal output for said known value of pressure,means for reading the measured output of said transducer at said known value of pressure,means for developing an offset correlated to the difference between said measured output and said known ideal output at said known value of pressure,memory means for storing data corresponding to said offset value, andcorrection means utilizing the stored data corresponding to said offset value for correcting all subsequent measured outputs of said transducer by adding or subtracting said offset value to said subsequent measurements of said transducer.

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