LumaSense Technologies INNOVA 1412i - Manual (Page 79)

Chapter 7
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BE6025-15 1412i Photoacoustic Gas Monitor LumaSense Technologies A/S
Page 79 of 202
Cross Interference: if any “interferent” other than water vapour is
present in the ambient air-sample, the Monitor can cross compensate
for the interference caused by its presence provided that a selective
optical filter is installed in the monitor to measure the concentration
of interferent gas present.
Gas Monitor Display / Averaging Period (1412i stand-alone use):
this enables you to decide if instantaneous values or averaged values
are displayed on the gas monitors screen.
If average values are desired, then the example below illustrates
how the values are calculated and displayed.
Let us suppose that the Monitor has been taking measurements
every 2.5 min., over a period of 30 min., of gas A (acetone), and
the following results (unshaded area) were obtained and recorded
in the display memory, for stand-alone users.
A: ACETONE
Averaged Values
0 11:42:30 1 66.72 mg/m 3 66.72 mg/m 3
0 11:45:00 2 154.90 mg/m 3 110.9 mg/m 3
0 11:47:30 3 271.30 mg/m 3 164.3 mg/m 3
0 11:50:00 4 415.90 mg/m 3 227.2 mg/m 3
0 11:52:30 5 588.70 mg/m 3 299.5 mg/m 3
0 11:55:00 6 789.70 mg/m 3 444.1 mg/m 3
0 11:57:30 7 1.019 g/m 3 616.9 mg/m 3
0 12:00:00 8 1.276 g/m 3 817.9 mg/m 3
0 12:02:30 9 1.562 g/m 3 1.047 g/m 3
0 12:05:00 10 1.876 g/m 3 1.304 g/m 3
0 12:07:30 11 2.218 g/m 3 1.159 g/m 3
0 12:10:00 12 2.589 g/m 3 1.904 g/m 3
Let us suppose that the averaging period was set to 10 min. When
the above measurement results are displayed on the screen and
the averaging function is activated then each measurement will be
averaged over the previous 10 min. and the averaged
measurement results will replace the individual measurement
results (averaged results are shown in the shaded area in the list
above). For example: measurement number 7 would be 616.9
mg/m 3 . This is the average of the 5 measurements taken in the
10 min. period ending at 11:57:30. Measurement number 12
would be 1.904 g/m 3 which is the average of the 5 measurements
taken in the 10 min. period ending at 12:10:00.