Density Meter LB 444 SECTION 2. SYSTEM DESCRIPTION
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sk2: Calculate
Calibration
Calibrate mode
none/lin/squ/cub/auto
Select the calibration mode.
none: One-point calibration. For this you only need one value pair (countrate
and density or concentration value) and the absorption coefficient. For
common products it can be taken from the table in the Appendix and en-
tered at Coefficient a1 (see also section 6.2 Calibration Method).
lin: Linear curve fit . This mode is used when at least two value pairs are
available. It should also be used when several calibration points are avail-
able which are very close together, so that not the entire measuring range
is covered by samples. For more information see section 6.2 Calibration
Method.
squ Square curve fit can be selected when at least 3 calibration points are
available which are distributed fairly evenly over the measuring range or
when the measurement is carried out in %-concentration, °Bx or in an-
other unit of measure which is not in linear correlation with the density.
cub Cubic curve fit should be applied when the same conditions exist as under
squ, but at least 4 value pairs are available and it becomes apparent dur-
ing operation that in some parts the value deviate when using squ.
auto The program automatically selects the best curve fit . Square or cubic
curve fit are used only when it can be ruled out with 95% probability that
the values correspond to the curve only by chance (check by means of f-
test).
At least 4 value pairs must be available for this function.
Upon selection of the required calibration mode and pressing of the
<
en-
ter
>
button, the calibration factors are calculated.
Exception: one-point calibration
Coefficient a1
Linear absorption coefficient (range -10 to +10).
Enter this coefficient for one-point calibration . One-point calibration is carried
out as soon as you press the <
enter
> button.
In all other cases, the program calculates the coefficient.
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