UEi Test Instruments KM9106/P - Manual (Page 61)

KM9106 Operators Manual 61
B. NOx CALCULATIONS
ONLY an NO Sensor fitted.
working in ppm: NOx referenced to NO
The user can select the assumed NO
2
percentage and the O
2
normalised level
then:
NOx in ppm = NO in ppm multiplied by (1 + assumed NO
2
percentage)
in this setup NOx can only be displayed as NOx = NO
then normalising:
NO in ppmn = NO in ppm multiplied by (21 minus the O
2norm
setting)
and then divided by (21 minus the actual O
2
reading)
For a worked example assume:
NO is 1000ppm
NO
2
is 5% of NO
O
2norm
is set to 3%
actual O2 is zero
NOx in ppm = 1000 x (1 +5/100) =1000 x1.05 = 1050 ppm
NO ppm n = 1000 x (21 - 3)/(21-0) = 1000 x 18 / 21 = 857 ppm n
NOx ppm n = 1050 x 18 / 21 = 900 ppm n
or
NOx ppm n = 857 x 1.05 = 900 ppm n
working in mg/m 3 : NOx referenced to NO or NO
2
The user can select the assumed NO
2
percentage, the O
2
reference level and whether
the NOx reading is referenced to NO or NO
2
referenced to NO
NO in mg/m 3 = NO in ppm multiplied by 1.34
NOx in mg/m
3 = NO in mg/m 3 multiplied by (1 + assumed NO
2
percentage)