B-H90.0.01.DB2-2.1
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Operation and maintenance | 7
7.3
CO
2
adjustment
In order to improve the accuracy, the carbon dioxide sensor can be adjusted. In order
to conduct a CO
2
adjustment, proceed as follows.
1-point adjustment
Used for optimisation of the accuracy at the adjustment point. The best possible accu-
racy can be achieved even with elevated CO
2
concentrations
2-point adjustment
Used for optimisation of the accuracy for extreme requirements over a wide measuring
range beginning from 0 ppm.
Basic sensor adjustment
Used to reset the sensor in case of deviations beyond the normally expected devia-
tions. The values of all prior adjustments are reset and cannot be restored. A plausibil-
ity check of the carbon dioxide concentrations does not take place. Depending on the
setting, adjustment to 0 ppm CO
2
test gas or fresh outside air can take place. Ensure
that the setting of the gradient compensation setpoint
[.SL
was entered correctly in the
Expanded settings
menu.
If reliable values can no longer be displayed, we recommend performing basic sensor
adjustment of the zero point at 0 ppm CO
2
with nitrogen and a possibly necessary ad-
ditional gradient compensation via 1-point adjustment.
If incorrect values are displayed after the adjustment, e.g.
ERR.2
at 0 ppm CO
2
, the
adjsutment must be repeated.
NOTE
Adjustment can be carried out in clean ambient air or with test gases (optionally avail-
able gas extraction device recommended). 1-point adjustment at any arbitrary point
above 350 ppm and 2-point adjustment at 0 ppm and an arbitrary point above 350
ppm are both possible.
For automatic adjustment, open the
Adjustment
menu.
–
The product is switched on.
–
Clean ambient air or test gas for gradient correction
–
Test gas 0 ppm CO
2
for zero point adjustment for 2-point adjustment or basic sen-
sor adjustment at 0 ppm
–
Gas extraction device, if applicable
Description
Prerequisite
