USER GUIDE
Gas Sensing Solutions Ltd.
Revision 1.2, 29 March 2021
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Copyright © 2021 Gas Sensing Solutions Ltd.
AUTO-ZERO FUNCTION
The sensor has a built-in auto-zeroing function. To function correctly, the sensor must be exposed to
typical background fresh air levels (~400ppm) at least once during the auto-zero period. The auto-
zero function uses the information gathered during these periods to re-zero. The sensor will reset
the ‘zero’ level
every time it does an auto-zero. Auto-zeroing is enabled by default. If the sensor is
powered down, the auto-zero is reset to default fresh air value, 400ppm. The user can change this
default value.
The auto-zero function works in the same way as the
‘Ambient’
command.
AUTO-ZERO INTERVALS
The auto-zero period can be programmed by the user. For the CozIR®-Blink-N, an auto-zero is set
based on the number of sensor power cycles.
Add the number of power cycles in the ‘No. Cycles’
data entry box and click ‘Auto Zero’.
AUTO-ZERO LEVEL
The background concentration will depend on sensor location. Ambient levels are typically in the
range of 400ppm - 450ppm. The factory default is set to 400ppm. The user can change the
background ambient level used for auto-zeroing. The value is stored in the sensor.
Typically, it is set to the same value as the ambient value, but it can also be set at a different level if
desired. To write a different fresh air CO
2
concentration value to the sensor used for auto-zeroing,
the command must be sent to the sensor manually using the software terminal mode. For more
details on how to adjust the auto-zero fresh air CO
2
concentration value, see the full data sheet at
https://www.gassensing.co.uk/products/