Calibration Diagnostics - Mettler Toledo thornton Bedienungsanleitung

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Measurement points immediately before and after the
UV unit are typically close together and should read the
same when the UV unit is off. Therefore one point can be
calibrated to match the colorimetric result and then the
second point can be calibrated to match the first point.
A separate colorimetric measurement must be made for
end of distribution loop, because normal ozone decay
can cause a significant drop in the concentration.

Calibration Diagnostics

The zero current value is recalculated whenever a zero cali-
bration is performed. The displayed value is in nanoamps
and is typically within ± 1 nA for a functioning sensor.
The slope is recalculated whenever a slope calibration is
performed and is typically within – 0.05 to –0.35 nA / ppb
ozone. The table below summarizes calibration data
nomenclature and ranges. The slope values are displayed
with negative (–) polarity.
Zero (air)
Calibration
Zero current:
± 1 nA
A continuous trend of slope values in one direction after
several calibrations can indicate that the sensor is drifting
and needs electrolyte (and possibly membrane) replace-
ment. Slope values that move up and down may indicate
limitations of the repeatability of the reference measurement.
pureO
3
Dissolved Ozone Sensor
pureO
Slope
Calibration
Slope:
– 0.05 to
– 0.35 nA / ppb
ozone
© 07 / 16 Mettler-Toledo GmbH
Dissolved Ozone Sensor
3
Printed in Switzerland