Single Point Calibration; Dual Point Calibration - Mettler Toledo InPro 6900 Série Instructions D'utilisation

InPro 6900 Series O

5.2.3 Single point calibration

By carrying out a single point calibration, the factual
slope of the sensor can be established. The calibration
medium can be water with known oxygen saturation
index (e.g. air-saturated water) or air with known
water-vapor saturation (e.g. water-vapor saturated
air).
After the sensor signal has stabilized, the complete
meas uring system can then be calibrated to the100 %
value of the desired measurable variable, e.g.100 %
air, 20.95 % O
normal pressure (see instruction manual for the
transmitter).
Single point calibration should be sufficient for almost
all process applications.

5.2.4 Dual point calibration

By carrying out a dual point calibration both slope and
zero point of the sensor can be established.
Important! In case of a dual point calibration, always
start by the zero point calibration before calibrating
the slope.
Due to the very low zero current of METTLER TOLEDO
sensors, dual point calibration is normally not nece -
ssary for standard applications.
As a rule, the zero point should be adjusted to zero
manually, or it is automatically performed by the trans-
mitter (see instruction manual for the transmitter).
A zero point calibration is only advisable if very high
accuracy is required at low oxygen concentrations.
Attention! Incorrect zero point calibration is a
frequent source of measurement error. For correct
calibration, we recommend the use of nitrogen gas
or other oxygen-free medium with a level of purity
of at least 99.995%.
After the sensor signal has stabilized (after 20...30
minutes), the sensor can be calibrated through the
relevant transmitter to the 100 % value of the desired
measurable variable, e.g. 0 % air, 0.0 % O
0.0 ppm (see instruction manual for the transmitter).
© 05 / 15 Mettler-Toledo AG
Printed in Switzerland
Sensor 12 mm
2
, or 8.26 ppm at 25 °C (77 °F) and
2
19
, or
2
InPro 6900
52 201 029