Martek MARK 22 Operation Manual page 30

5 - CALIBRATION
ZERO
TEMPERATURE
Select "ZERO". The display will prompt
w i t h :
AUTO
ZERO TEMPERATURE
Select "MANUAL".
the display will prompt with a momentary
message:
PLACE SENSOR IN
LO TEMP STANDARD
Then will ask you to:
HIT KEY W/STABLE
-0.0012 VOLT
Like the auto temperature calibration, the
Mark 22 acts like a voltmeter and shows a
varying voltage. At this time, place the tem-
perature sensor in a temperature ice bath or
a beaker filled with water and crushed ice.
At the same time, measure the temperature
of the ice slurry with an accurate thermom-
eter.
NOTE: The freezing point of water does not ac-
tually have to be reached for the Mark 22 to de-
termine the sensor's reading at 0
the temperature low point is lower than that of
the samples, a value above the freezing point of
water can be used. For example, if your range of
measurement is between 10
could calibrate the Mark 22 for temperature us-
ing 5 and 40 as your low (zero) and high (span)
o o
points.
26
SPAN
MANUAL
After a short delay,
C. As long as
o
and 30 C, then you
o o
When the voltage reading on the display
has stabilized, depress the SELECT key. The
Mark 22 will prompt with the following dis-
p l a y :
INP 4 DIGIT STD.
LO TEMP = 00.00
Input the temperature value as a 4-digit
number (note the fixed decimal point). The
value of the flashing digit may be altered by
pressing the UP or DOWN ARROW
Move forward to the next digit by pushing
SELECT key. Move back to a previous
the
digit by pushing the EXIT key.
Temperature Span
After the Mark 22 has been zeroed for
temperature, it will automatically prompt
with the following display:
AUTO
SPAN TEMPERATURE
Select "MANUAL".
the display will prompt with a momentary
message:
PLACE SENSOR IN
HI TEMP STANDARD
Then will ask you to:
HIT KEY W/STABLE
+0.7883 VOLT
At this time, place the sensor in a high
(span) temperature bath where the tempera-
ture is approximately twice the sample tem-
perature. To accurately measure the water
temperature, place a thermometer into the
keys .
- Calibration•
MANUAL
After a short delay,
Martek Instruments, Inc.