ZIROX SGM7, Руководство пользователя

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Oxygen Monitor SGM7 8 Operation
HB_SGM7_eng.docx
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8.3 Calibration
For measurements with high accuracy requirements a calibration is highly
recommended (The high stability of the measuring cell requires one check-
up per a year only!).
The device must be in operating state
for a minimum of one hour before the
calibration!
8.3.1 Zero calibration
The zero calibration serves the balance of the offset voltage of the ZrO2-
sensor. The offset is caused by the construction (when the electrode has a
disadvantageous position in the heating field) and can occur due to aging of
the sensor.
Before calibration, the sensor is flushed with ambient air. The gas flow is set
by internal or external pump at the value which is used for measuring the
measuring gas.
With the zero calibration, the working point in ambient air is calibrated with
20.64 vol.% O2.
First select “Calibration” and then “Calibration ZERO POINT” via keypad.
Select “CALIBR. ZERO:” and start the calibration by pressing “ENTER”. After
approx. 5 sec the calibration is finished. Leave the calibration by pressing
„RETURN“ and „ENTER“. Save it with „YES“.
8.3.2 Span gas calibration
Certified test gas (oxygen concentration near future measuring conditions)
must flow through the device.
First select “Calibration” and then “CALIBR. SPAN GAS” via keypad. Set the
test gas oxygen concentration. Select “CALIBR. SPAN:” and start the
calibration by pressing “ENTER”.
The stability of the measuring value is checked during the calibration. The
real calibration process starts as soon as the signal produced by the test gas
is stable. Therefore, the duration of the calibration process can vary (variation
smaller than 1 % in 4 seconds).
If the stability is not given, the calibration is stopped after 60 seconds.
Furthermore, the deviation of measuring value from set value is evaluated.
At zero point calib/- 20 mV (cell voltage), at span gas calib/-
20 % of measuring value (cell voltage) are allowed.
For the adjustment the following equation applies: U
z
(korr)=(Uc
ell
+A)*B
U
z
= measured cell voltage
A = cell voltage at zero point
B = factor for final value correction
Leave calibration by pressing „RETURN“ and „ENTER“. Save with „YES“.