Auto Temperature Calibration; Manual Temperature Calibration - Martek MARK 22 Operation Manual

5.1.1

Auto Temperature Calibration

To set the instrument up for automatic
temperature calibration, press the SETUP.
The Mark 22 then displays the main Setup
Menu. Select the CAL option from the menu.
The display then appears as follows:
TEMP
pH
Select "TEMP".
w i t h :
ZERO
TEMPERATURE
Select "ZERO".
w i t h :
AUTO
ZERO TEMPERATURE
Select "AUTO". After a short delay, the
display will appear as follows:
HIT KEY W/STABLE
-0.0032 VOLT
At this time, the Mark 22 acts like a volt-
meter and shows a varying voltage. An in-
ternal relay has switched in the precision re-
sistors simulating a temperature of 0
voltage displayed will vary from monitor to
monitor). Allow the displayed voltage to sta-
bilize. When the voltage shown on the dis-
play is stable, depress the SELECT key. Af-
ter the SECLECT key has been pressed, the
display will prompt
ZERO" and then automatically default to
Martek Instruments, Inc.
COND
TIME
The display will prompt
SPAN
The display will prompt
MANUAL
C (the
o
with "TEMP AUTO
CALIBRATION - 5
"SPAN". At this time, press the SELECT key.
The display will prompt with:
AUTO
SPAN TEMPERATURE
Select "AUTO". Again, after a short de-
lay, the display will prompt with a momen-
tary message:
HIT KEY W/STABLE
+0.7883 VOLT
Again, the Mark 22 acts like a voltmeter
and shows a varying voltage.
relay has switched in the precision resistors
simulating a temperature of 50
the SELECT key when the displayed volt-
age has stabilized. After the key has been
pressed, the display will prompt with "TEMP
AUTO SPAN" and then automatically default
to "COND".
5.1.2 Manual Temperature
Calibration
The Mark 22 may also be calibrated us-
ing external reference points. A constant tem-
perature bath would provide the most use-
ful reference, however, ice and hot water can
also be used if a temperature bath is not avail-
able. Also, make sure the temperature sen-
sor is connected prior to operating the Mark
22 ( section 3.2.3 ).
Temperature Zero - Calibration
Depress the SETUP key and select "CAL"
and then "TEMP" from the display menus.
The display will prompt with:
MANUAL
An internal
C. Depress
o
25