Testing The Sensor Via A Transmitter - Mettler Toledo InPro 6850i Bedienungsanleitung

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If the green LED lights up the current for air
measurement is within the admissible range.
If the LED does not light up, you should check the
battery of the O
manual "Accessories"). If the battery is working,
than there is probably a problem with your sensor.
You should change the electrolyte and/or the
membrane body of your sensor. If after a
membrane change the LED still does not light up,
this means that there is maybe something wrong
with the interior body of the sensor. You should
then change it (see "Section 6.2").
Important! The Sensor Check function only verifies
the correctness of the electrode current for air
measurement. In order to be absolutely sure of the
functionality of the sensor, the residual signal in
an oxygen free medium should also be controlled
(see "Section 6.1.3").

6.1.3 Testing the sensor via a transmitter

A periodic zero current measurement (no zero point
calibration!) is recommended for verification of prop-
er sensor function.
Note: At the time you carry out the zero current
measurement, the sensor must be polarized.
Zero current measurement can be done by using
zeroing gel (order no. 34 100 1032) or nitrogen (N
or carbon dioxide (CO
purity of at least 99.995 %, alternatively in a sample
medium saturated with one of these gases.
After 2 minutes in an oxygen-free sample medium,
the reading on the transmitter should drop to
below 10 % of the reading in ambient air, and
within 10 minutes the value should have dropped
to below 1 %.
If the measured values are too high, this suggests a
depleted electrolyte or a defective membrane. In the
first instance replace the electrolyte, and in the sec-
ond case exchange both the membrane body and the
electrolyte accordingly.
If after such procedures the above mentioned values
are still not reached, replace the interior body. If this
doesn't solve the problem too send the sensor to your
local METTLER TOLEDO representative for inspection.
InPro 6850i, 6900i, 6950i
52 206 349
InPro 6850i / 6900i / 6950i O
sensor master (see instruction
2
) calibration gases with a
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© 02 / 09 Mettler-Toledo AG
Sensor 12 / 25 mm
2
Printed in Switzerland
)
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