33
SECTION 4, continued
lighter color at increasing concentrations. The zero concentration
standard is usually produced by combining deionized water with
the reagents. Commonly this solution is used to zero the
instrument as in Step step 14 of Section 4.4 Creating a New User-
entered Program.
Once the zero is entered, the prepared standards must be read
from lightest to darkest. In the case of bleaching chemistries, the
absorbance values reported by the colorimeter may be negative.
Even when your test produces a lower absorbance (lighter color)
with increasing concentration, the prepared standards must be
read by the colorimeter in the order of increasing absorbance (i.e.,
from colorless or the palest color, to the deepest color). The
instrument will not accept standards read out of order.
4.4 Creating a New User-entered Program
Use the step-by-step instructions below to enter a new user-
entered program into instrument memory. Terminate at any point
(before the program is stored) by pressing the
EXIT key until the
display is blank. The colorimeter will not retain any of the
entered data.
1. Press the
I/O key to turn on the instrument.
2. Press the
SETUP key. The display will show SETUP in the
upper-left and the down-arrow icon in the lower-right.
Available action functions are also shown.
3. Press the down
ARROW key until USER is displayed.
4. Press the up
ARROW key if the display goes past USER.
5. Press the
ENTER key. Four horizontal lines (numeric entry
display) will be displayed.
6. Select a program number from 101 through 110 by pressing
the corresponding digit key. The number will appear in
the display.
Note: Press CE to correct errors.
7. Press ENTER. A wavelength and nm will be displayed.