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The correction factor is calculated:
Correction factor
This results in the following correction factor:
100
= 1.0526
(100 – 5)
For the gas mixture, the corrected total interference is therefore calculated to a good
approximation:
1.0526 x -0.1123 by volume% = -0.1182% Vol. %
The corrected total cross-sensitivity with change of prefix sign can now be used to correct the zero
point calibration. In this example the zero point would be adjusted to +0.1182% by volume.
A neglect of the cross sensitivity, in this example, would mean a relative error of about 2%.
N O T I C E !
12.2
END VALUE CALIBRATION
Before the measuring range end value is calibrated, review of the zero point must always be made.
The procedure during calibration is as follows:
Set test gas flow rate with a needle valve or flow metre to a maximum. 60 l/h. The volume
flow of the calibration gas should always correspond to the gas volume flow;
Wait approx. 30 seconds until the display has stabilised.
If necessary, adjust, using the end value potentiometer the O
e.g. in the case of air to 20.9% = 7.344 mA in a measuring range 0 - 100% = 4 - 20 mA.
16
=
After zero point
always be calibrated!
Gas sampling and gas conditioning technology
100
(100 - O2 concentration)
calibration the measuring range end value must
value of the test gas,
2
9-3.20-MD
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