8.4Calibration concentration setting (zirconia O2 sensor)
A zirconia O2 sensor sets the zero (air) point (span point stipulated in the laws for measurement and weighing) of the O2 analyzer. For the density of calibration gas to be used, refer to “8.2 Preparation of standard gas”.
✩Setting of calibration concentration for zero (air) point (zero stipulated in the laws for measurement and weighing)
By pressing the FUNC key in the measuring status,
the calibration concentration previously set for the zero (air) point will appear on the main indication.
The CAL SET LED of the function indicating lamps will flicker.
By pressing the 
key, the higher digit of the main indication of the O2 analyzer will flicker and zero point setting is enabled.
Press the 
keys to select a range.
The numeric value will be incremented by pressing
key. The digit to be set is selected by pressing the
key.
Setting ranges are 20.2 to 21.9 Vol. % for high range and 7.0 to 21.9 Vol. % for law range.
Set the air concentration for both high and low range.Note)
Press the ENT key after setting the zero point. Set- ting operation is completed.
O2
FUNC
O2
CAL SET
O2
O2
ENT
O2
Note: When using air for the high range and 9 to 10 Vol. % O2/N2 for the low range, set the density for each range.
When viewing from the zirconia O2 sensor side, the air point corresponds to the zero point. Therefore, calibration should begin with the air point.
Also, since the air point and low concentration point can be calibrated by the zero calibra- tion key and span calibration key, respectively, the air point and low concentration point are regarded as the zero and span in this manual.
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