[Prt LOG]: Permits to send the stored values to a printer or computer.
1.
Select the set-up procedure by pressing
MODE
and press
CAL.
2.
Choose [Prt LOG] with
¿
or
À
and press
CAL
3.
The display shows [PrintinG] while all data-logged values, including
corresponding dates and times, are sent to the RS232 output in the
following format, compatible with EXCEL™, LOTUS 123™,... The
columns are separated by a TAB character.
6
Printing data
MEASUREMENTS
The measuring electrode should be connected to the coaxial INPUT
connector. Its banana plugs should be inserted in the °C terminals.
Inputs
Theory
Principle:
The oxygenmeter and its electrode function according to the Clark
principle with platinum as cathode and silver as anode in an electrolyte
cell to which a polarisation voltage of 800 mV is applied. Oxygen gas
present in the electrolyte is reduced to OH ions at the platinum cathode.
The resulting current is diffusion limited and therefore proportional to the
oxygen concentration in the sample solution. This current is amplified,
corrected, and displayed in mg/l, ppm or % dissolved oxygen.
Electrode:
The anode and cathode of the electrode are immersed in a special buffer
solution inside the electrode, to give high stability readings and short
polarisation times. The electrolyte compartment is separated by a PTFE
film from the sample solution. Only gases, but no ions, can diffuse through
this film from the sample solution into the internal electrolyte.
Temperature compensation:
Speed of electrode reactions depends on temperature. Therefore, for a
given oxygen concentration, the electrode current becomes greater at
higher temperature, and conversely. This temperature effect is
compensated with the NTC resistor incorporated in the electrode. For
aqueous solutions the oxygen meter therefore always gives correct
readings in ppm, independent of the actual temperature.
Log#
VALUE
UNIT
C
H
D
001
7.34
ppm
23.7
13:19:57
29/01/95
002
7.21
ppm
23.7
13:20:57
29/01/95
003
7.08
ppm
23.8
13:21:57
29/01/95
004
6.71
ppm
23.8
13:22:57
29/01/95
005
6.49
ppm
23.9
13:23:57
29/01/95
