PM400 Multi-Gas Personal Monitor
REV – 2.0
[34-2900-0206-2 ]
20
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P a g e
6
Calibration
Calibration is the process of adjusting the sensor’s response by using a specific concentration of calibration gas.
Sensors will drift for a variety of reasons, so it is important to perform a full calibration periodically to ensure that
the sensors response to the target gas are accurate. A full calibration consists of two points, a Fresh Air Calibration
and a Span Calibration.
Fresh Air Calibration
adjusts the zero offset of the toxic and LEL sensors or sets the oxygen sensor to 20.9% Vol.
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.
CAUTION
For O
2
units: Initial calibration is performed on all devices prior to shipment. Once
received, calibration should be performed monthly (or quarterly) depending on
frequency of use.
All alarms are muted during calibration.
6.1
Accessing the Calibration Menu
To access the calibration menu:
1.
Press the [Function key] to navigate to the Calibration screen.
2.
While the Calibration screen is displayed, press and hold down the [Function key] for 5 seconds to access the
Calibration mode.
3.
Press the [Function] key to cycle through the menu. The calibration menu has four items: Fresh Air Cal., Span
Cal., Bump Test, and Exit.
6.2
Fresh Air Calibration
Fresh Air calibration
adjusts the zero offset of the toxic and LEL sensors and sets the oxygen sensor to 20.9% Vol.
WARNING
Fresh Air Calibration must be performed in a clean environment that is free from other
gases (calibration is assumed to be performed in an environment with an Oxygen
concentration of 20.9% Vol.). Fresh Air Calibration should not be performed in a
confined space.
