PureAire Monitoring Systems, Inc.
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1.1.3 Calibration
The
Air Check
O
2
monitor incorporates a stable zirconium oxide sensor that rarely requires
calibration. Changing barometric pressure changes or changes in temperature and humidity do not
affect the zirconium oxide oxygen cell. The earth is a wonderful source of calibrated oxygen at 20.9%,
therefore under ambient conditions verification of the
Air Check
O
2
monitor to 20.9% oxygen is
constantly being performed. There are no zero or span pots to adjust. The O
2
monitor only requires
periodic testing with nitrogen to verify the cells response to low oxygen levels. See Section 6.2 for
the testing procedure to nitrogen.
1.2 Component Identification
1.2.1 Front View Exterior
1.
Digital Display
— 3-digit backlit LCD digital display for showing the
oxygen levels in percent.
2.
Joystick
— Used for selecting and adjusting the built-in menus. The
Air
Check
O
2
monitor is available with optional dual level user selectable
relays. The joystick is also used to select alarm levels, relay settings and
resetting any latching visual and audio alarms.
3.
Cable Port
— This is the opening in the transmitter housing for connecting
the 4-20 mA output and 24 VDC power cable.
4.
Sensor Protector
—The O
2
sensor is heated and the sensor protector shields
the cell as well as provides airflow to the cell. It also has a ¼ “ diameter tube
fitting to permit connecting a nitrogen cylinder for testing the O
2
cell
response.
NOTE: The sensor protector will feel HOT to the touch. This
is normal.
5.
Oxygen Sensor
— A zirconium oxide sensor, which detects and measures
the level of oxygen. When exposed to oxygen, the sensor outputs an
electrical signal proportional to the actual concentration of oxygen.
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8
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8
6
4 & 5
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2
7
9
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