Hach DR/2010 Instrument Manual page 70

Note: With option
a the instrument
should be zeroed
with the solution
that will be used
to zero the
instrument when
actually running
the stored user
program.
Note: It is not
important what is
used to zero the
instrument when
entering points for
options b and c.
In fact, the cell
compartment may
be left empty.
23. Press the
DOWN ARROW
 &&&&
At this point, the user has three options to "teach" the instrument how
to convert absorbance to the appropriate concentration:
a) Enter Concentration and Measure Absorbance
Create a calibration table by entering concentration values for the
standards, then measuring the absorbance of the standards. Enter
calibration points one at a time. First enter the concentration using
the keys, then read the absorbance of the developed standard.
NUMERIC
The instrument uses a piecewise linear curve as the default, but
will fit the data to all four types of curves (the analyst chooses the
best curve), or a calibration curve can be selected from the printed
graph of the data points. To enter a calibration curve using this
option, press
24-44, below.
b) Enter Concentration and Absorbance
If calibration data has already been collected by other means,
create a calibration table by entering concentration values for the
standards, then entering the absorbance values of the standards.
The instrument uses a piecewise linear curve as the default, but
will fit the data to all four types of curves (analyst chooses the best
curve), or a calibration curve can be selected from the printed
graph of the data points. To enter a calibration curve using this
option, press
24-44, below.
c) Direct Coefficient Entry
If you can determine the mathematical relationship (calibration
curve) between absorbance and concentration using other software
(i.e., Excel, Tablecurve...), enter the coefficients for the type of
equation (below) you choose to use.
Four types of mathematical relationships between absorbance and
concentration exist:
. The display will show:
# &&&
+= E>6=> A
at the
Calib Table: 0
ENTER
at the
Calib Table: 0
ENTER
70
nm
display. Follow Steps
display. Follow Steps