9
Relative O
2
measurement:
1.
While in the O
2
range, press
¿
. At that moment the instrument stores
the actual value and automatically subtracts it from all next
measurements. You can repeat this as many times as required. A
blinking [r] in the display appears.
2.
To cancel relative readings, press
MODE
and you will be in the
normal measuring mode again.
Relative
measurement
∗
You can also check the saturation-current (nA) and the saturation-
point (ppm) by pressing
À
sequentially: e.g. [Cur=67.9] & [Sat=8.73].
See also GLP-protocol.
∗
The instrument will refuse automatic standardisation when the
electrode is unstable. A worn electrode may be the cause. Select a
lower resolution for a more rapid standardisation or replace the
membrane and electrolyte of the electrode!
∗
After replacement or refilling of the measuring head the first
polarisation of the electrode could last ±15 minutes!
∗
Press
RES
to change the resolution from 0.1 to 0.01 ppm or from 1
to 0.1 %.
Measurement:
1.
Read temperature by pressing
°C
.
Calibration:
1.
Press
CAL
to calibrate the °C scale with any reference. Immerse the
electrode in a solution of known temperature.
2.
The display shows e.g. [°C=22.3]. Calibrate to the proper value with
¿
or
À
and press
CAL
again or press
RES
to reset the absolute
readings.
Temperature
measurement
Recorder output
A recorder can be connected to the (+) and (-) terminals. The 0 to 2 V
output range corresponds with 0 to 60 ppm or 600 %. Use only laboratory
recorders with a high input impedance!
GLP-protocol
1.
Select the O
2
range (ppm or %) by pressing
MODE
.
2.
Check the saturation-current (nA) and the saturation-point (ppm) by
pressing
À
sequentially: e.g. [Cur=67.9] & [Sat=8.73].
3.
Press
to print a complete calibration report, e.g.:
DATA COMMUNICATION
