Automatic calibration of the sensors used in a miniature STD instrument

Abstract

The paper describes a system for simplified calibration of a new STD instrument. When measuring, the raw data from the instrument conductivity, temperature and pressure sensors are fed into a microprocessor inside the instrument. The microprocessor computes the calibrated primary data by inserting the raw data into an equation of the form Y= A+B.X+C.Xexp2 where A,B and C are calibration coefficients. The new instrument automatically computes and inserts these calibration coefficients itself when exposed to a temperature bath, a conductivity bath and a pressure reference with a few known values.