Information for accurate measurements
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Span calibration
Span calibration matches a measured value with an analyzed value. Since the span sensitivity
of the light transmission method does not change, it is not intended to calibrate variations in
sensitivity on the instrument side. A span coefficient is calculated to obtain a correlation
between a measured value and an analyzed value, and to match a measured value to an
analyzed value. The default value of a coefficient is 1. It can be adjusted from 0.5 to 2.
Moreover, a wing curve can be selected according to sample properties.
Measured value × Span coefficient = Analyzed value
The inclination of a linear regression line which passes the origin becomes a span coefficient.
For a graph, if a span coefficient is set at 0.9499, a span coefficient corresponds to nearly an
analyzed value.
Correlation graph between instrument
measurement and analyzed value
Analyzed value
mg/L
Analyzed value mg/L
Linear (analyzed value mg/L)
Instrument measured value mg/L
