Calibration; Zero Calibration Procedure - Mettler Toledo thornton Bedienungsanleitung

10

Calibration

Calibration of the sensor calculates new calibration con-
stants for the sensor (zero current and a slope). The zero
current is normally in the range between ±1 nA. The slope
is normally in the range between –0.05 and –0.35 nA / ppb
ozone.
Calibration data for a sensor used with the M800 can be
viewed under the CAL / Edit menu for the appropriate channel.
For most applications, ozone-free air or water provides the
most reliable standard for the zero current calibration.
Note: To achieve full polarization and proper operation, the
sensor must be connected to a powered instrument and in
in a process sample with > 50 ppb of ozone concentra-
tion for at least 6 hours before calibrating or measuring to
obtain rated accuracy. For best results a recalibration (slope
adjustment) after 24 hours of operation is recommended.
For strategies on polarization and calibration of sensors
where ozone is not normally present, see the Appendix at
the end of this manual.

Zero Calibration Procedure

Zero current calibration should be performed at infrequent
intervals thereafter since it does not normally change sig-
nificantly. A zero calibration changes the zero current from
the factory value.
1. The HOLD function in the instrument will activate
automatically according to user settings. See the
transmitter's manual for instructions on program-
ming HOLD settings.
2. Shut off the sample flow to the flow housing and,
while keeping the sensor connected electrically,
remove the sensor and hang it in open air (be sure
that all liquids which can contain ozone are flushed
away and that the sensor membrane is dried with a
lint free cloth).
3. Wait for a stable ozone reading, typically for 15 min-
utes. The instrument should give a stable reading at
less than 1 ppb before initiating the calibration.
4. Proceed through the instrument CALIBRATION menu.
Perform a one-point zero calibration.
pureO
3
Dissolved Ozone Sensor
pureO Dissolved Ozone Sensor
3
© 07 / 16 Mettler-Toledo GmbH
Printed in Switzerland