The concentration calibration of the inline refractometer PR-33 is organized in six
layers.
The calibration of each refractometer can be
verified using standard refractive index liquids, see Refractometer verification.
Field calibration determines the appropriate adjustment to CALC. The adjusted
concentration is called CONC. If there is no adjustment, CALC and CONC are equal. Thus the
chemical curve is kept intact as a firm base for the calculation, the adjustment is merely
additional terms.