14
4 - OPERATION
Martek Instruments, Inc.
above 5.9 Volts to prevent degradation of the
battery.
The first line of the conductivity screen
displays the temperature-compensated con-
ductivity (S/cm) measured by the reference
cell. The second line of the display shows the
raw conductivity (mS/cm) measured directly
by the cell followed by the measured tem-
perature (°C).
The first line of the pH screen shows a
pH which has been compensated for tem-
perature with both a correction for the ex-
pected voltage change (Nernstian correction)
and a correction based on the ionization of
the solution (not necessary in solutions with
high ionic conductivity). The second line of
the display shows a pH measurement which
has been corrected only with the Nernstian
correction and the measured temperature.
These
RANGE
keys allow the Mark 22
to select one of three conductivity ranges
when the Mark 22 is monitoring conductiv-
ity in the MANUAL mode. The YELLOW
ARROWS indicate which direction the con-
ductivity range can be altered. If the
UP AR-
ROW
key is depressed, the Mark 22 will
move the decimal point shown in the display
to the right. If the
DOWN ARROW
key is
depressed, the Mark 22 will move the deci-
mal point to the left. This feature allows you
to select a low, medium, or high range of mea-
surement. An example of the
RANGE
keys
functions are shown below .
UP arrow
1.3042
µ
S C Cond
1.4523
µ
S 28.15° M
01.304
µ
S C Cond
01.452
µ
S 28.15° M
UP arrow
4.1.2
Setup Mode
The SETUP mode allows the user to cali-
brate sensors, select temperature compensa-
tion formulas, change cell constants, set date
and time, and to set up the start time and
interval for the logging function. The
SE-
LECT Key
is used to select options from a
displayed menu. The
UP ARROW Key
moves the blinking display down through
the menus or increments the displayed dig-
its when adjustment of a numeric input en-
try is required. The
DOWN ARROW Key
moves the blinking display up through the
menus or decrements the displayed digits
when adjustment of a numeric input entry is
required.
Depress the yellow
SETUP
key. The
Mark22 will display the following screen:
The Mark 22 utilizes a Setup Option
Menu format that provides the user with a
list of the available Setup Options. The user
is required to select from this list the desired
Setup operation to be performed. After the
SETUP
key has been depressed, the top row
of function keys are now in affect. All text
and symbols in YELLOW are now applicable
CAL
COMP
CELL
LOG
UP arrow
01.304
µ
S C Cond
01.452
µ
S 28.15° M
