Martek MARK 22 Operation Manual page 22

4 - OPERATION
From the SETUP Menu, choose the com-
pensation and press the select key. The dis-
play will indicate the following:
MARSH
GE
The operator must use the UP and
DOWN ARROW Keys, to navigate the dis-
play and highlight the desired compensation
formula. The option is chosen by user when
the SEECT Key is depressed while one of the
formulas is highlighted.
The flashing prompt will automatically
highlight the " SLOPE " option after the tem-
perature compensation formula has been se-
lected. The slope coefficient for conductivity
and pH can be altered by selecting the SLOPE
option and then choosing either conductiv-
ity or pH options.
To change a solution slope coefficient , use
the UP or DOWN ARROW Keys to increment
or decrement the displayed numeric value.
Depress the SELECT Key to enter and save
the displayed value and subsequently ad-
vance to the next the next digit. Use the EXIT
Key to backspace and edit a previously saved
va lue.
If conductivity is selected first and the
slope coefficient has been entered, the Mark
22 will automatically default to the pH solu-
tion compensation factor. The solution com-
pensation factor can be calculated for pH
using the following formula:
pH Solution
Compensation = pH @ Low Temp - pH @ High Temp
Coefficient
For example, if we use 1 ppm ammonium
hydroxide in ultrapure water, the above for-
mula would be as follows:
18
LIGHT
SLOPE
High Temp - Low Temp
pH Solution
Compensation =
Coefficient
10.20 pH @ 10° C - 8.96 pH @ 50° C
= 0.031 pH / ° C
50° C - 10 ° C
Martek Instruments, Inc.