Hach DR 2800, User Manual, Page: 96 / 96

96
Free Programming
Select Conc. Key
If an already defined formula, in this case C1, is to be taken into
account in the formula for C2, press
SELECT CONC
.
Enter the number of the formula (e.g. 1 for C1) and press
OK
to confirm.
Cn can now be linked with a mathematical operation.
Note: The Cn concentrations that are to be calculated are numbered in
sequence: C1, C2, C3, etc.
Note: When the first Cn formula has been defined, the Formula list is
automatically extended by Cn+1.
B.3 Entering Variables
See Table 17 on page 96 for variable definitions.
1. Select the Variables line in the data overview and press
EDIT
.
2. Select the variable to be edited, press
EDIT
and use the
alphanumeric keypad to enter the data specified in the working
procedure (for F1, F2,
λ
1, U1 etc.). Press
OK
to confirm
each entry.
Abbreviation of Variables:
F1: Factor 1
F2: Factor 2
λ
1: Wavelength 1
U1: Conversion Factor 1 for the first chemical form
U2: Conversion Factor 2 for additional chemical forms, etc.
B.4 Saving a Free Programming User Program
Press
STORE
to save the entered data. The data can be stored
under any data point (Measurement sequence, Formula, Timer,
etc.).
Table 17 Free Programming Variable Definitions
Variable Definition
Z Zero
R Reading
U Chemical form factor. U1 is the default chemical form factor and is always equal to 1
F1–F4 Calibration factors
K1–K4
Wavelength weighting factors; the sum or difference of the absorbance measured at different
wavelengths. K-values can be fractions (e.g. K=0.75) or negative (e.g. K=–1).
C1 Absorbance as a function of the Reading and Zero values (C1=R1–Z1)
C2
Concentration as a function of calibration factors and absorbance values.
The concentration formula is: (F1+F2 x C1+ F3 x C1
2
+ F4 x C1
3
) x U1