33
CALIBRATION - 5
Martek Instruments, Inc.
down. Move forward to the next digit by
pushing the
SELECT
key. Move back to a
previous digit by pushing the
EXIT
key. Once
the last digit has been entered, the Mark 22
will automatically respond with the follow-
ing display:
and the "TIME" option will be flashing. Press
the
SELECT
key. The display will then indi-
cate the following:
The "hh" stands for the hour and the "mm"
stands for the minutes. The time must be in-
putted as a 24 hour clock, i.e. 1:00 PM would
be inputted as 1300, 9:30 AM would be in-
putted as 0930, etc. Alter the value of the
flashing digit by pressing the arrow keys up
or down. Move forward to the next digit by
pushing the
SELECT
key. Move back to a
previous digit by pushing the
EXIT
key. Once
the last digit has been entered, the Mark 22
will automatically respond with the follow-
ing display:
Press the
EXIT
key to return to the moni-
toring mode.
5.6
F
REQUENCY
OF
C
ALIBRATION
Standard operating procedures for cali-
bration vary with each organization. Martek
Instruments recommends calibration of the
Mark 22 for all parameters at least once a
month. More frequent calibration may be
required if the displayed values are unusu-
ally high or low, or if the application itself
changes.
In general, pH sensors are unstable elec-
trodes and will require more frequent cali-
bration. Temperature and conductivity are
much more stable and will require less fre-
quent calibration.
DATE TIME
INPUT
hhmm
TIME
0101
CAL
COMP
CELL
LOG
