YOKOGAWA ZR22G User Manual page 122

(6) Select "Zero calibration". The screen of Figure 7.20 appears. Check that the oxygen
concentration value on screen matches the oxygen concentration value of calibration gas
that is actually used. Then select "Next".
Figure 7.20 Zero gas concentration check
(7) Follow the instructions in the display as in Figure 7.21 to turn on the zero gas flow. Open
the zero gas flow valve for the Flow Setting Unit and adjust that valve to obtain a flow of 600
± 60 ml/min. The valve should be adjusted by loosening its lock nut and turning slowly the
valve shaft counterclockwise. Use the calibration gas flowmeter to check the flow rate.
Figure 7.21 Zero gas flow rate check
(8) Similar to span calibration, selecting "Start calibration" displays the trend graph of the
oxygen-concentration reading being measured (Figure. 7.22) on screen. Wait for the
reading to stabilize near the zero gas concentration by monitoring the graph and the sensor
electromotive force. At this point, calibration is not yet executed, so it is acceptable for the
reading to deviate from the zero air concentration.
Figure 7.22 Trend in Zero gas calibration
<7. Startup>
IM 11M12G01-02EN 1sh Edition : Mar. 25, 2021-00
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