Sensitivity Adjustment - M&C PMA Series Instruction Manual

The correction factor is calculated as follows:
Correction factor = 
The correction factor is the following:
100
 = 1.0526
(100 – 5)
For the gas mixture the rectified sum cross sensitivity then is calculated in good approximation:
1.0526 x -0.1123 Vol.% = -0.1182 Vol.%
The rectified sum cross sensitivity with change of sign now can be used for the correction of the zero
calibration. In this case the zero point has to be adjusted at +0.1182 Vol.%.
In case the cross sensitivities would be ignored in the above mentioned example, this would result in a
relative error of approximately 2%.
N O T E !
16.2

SENSITIVITY ADJUSTMENT

Before doing the sensitivity calibration, a zero point calibration must have been completed.
Place the span selector switch to the measuring range in which the sensitivity calibration
•
shall be effected. It is recommended to make a calibration with dry and clean air in the
range of 25%. Place selector switch (4, see figure 2).
Connect a flexible PVC or Viton tube with ambient air or instrumental air or if applicable
•
with a pressure reducer of the test gas bottle. The pressure reducer shall have an output
range of adjustment of max. 0 - 1.5 bar.
Open the bottle or the instrumental air valve and afterwards open the closed pressure re-
•
ducer output valve and purge the pressure controller including the flexible tubing for ap-
prox. 5 seconds.
Check the adjusted regulating pressure and if necessary reduce it to ≤ 0.1bar, then shut
•
the pressure regulator output valve again.
Connect the free tube end of the instrumental air connection or of the test gas bottle con-
•
nection to the gas inlet of the analyzer.
Open slowly the output valve of the pressure regulator to avoid pressure peaks.
•
• Adjust the gas flow to approx. 50 l/h on the flowmeter.
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100
(100 – O -concentration)
2
After the zero point calibration the span final value has to be calibrated
too!
PMA45K1 | 1.00.01 21