PM400 Multi-Gas Personal Monitor
REV – 2.0
[34-2900-0206-2 ]
22
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P a g e
6.3
Span Calibration
Span calibration
adjusts the sensors response to gas to account for sensor drift. It is recommended to perform a
Fresh Air calibration prior to a Span calibration.
WARNING
When performing a Span Calibration only use certified calibration gas at the required
concentration level. Do not use expired calibration gas.
To perform a Span Calibration:
1.
On the Measuring screen, make sure O
2
reads 20.9 and the others read 0, 0, and 0.0. If the measuring screen
does not display the correct values, the user should perform a fresh air calibration (see section 6.2 Fresh Air
Calibration).
2.
Clip the calibration cap to the unit. The cap attaches to the recesses in either side of the unit. You should
hear a click when the cap is secure. Be sure you have the cap right-side up when attaching it.
6–1 Calibration Hood
NOTE:
The cap should be removed for a Fresh Air Calibration unless using a cylinder of zero air.
3.
Ensure that the regulator is firmly attached to the gas bottle and that the hose is securely attached to the
regulator and to the calibration cap.
4.
From the Main screen, press the [Function] key to advance to the Calibration screen. The calibration icon
and the Calibration gas settings are displayed. Typical readings from left to right are 50, 18.0, 100, and 25.
NOTE:
Pressing the key too quickly may not advance the display.
