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User's manual – Ver. 1.53 July 2015 67/75
6.4 Manual stability test
Stability test is conducted without flow to determine the performance of the light source –
detector pair.
To perform the stability test, select Operation/General/Stability test. Test runs for 20 minutes
at 1 s time resolution. Stability test data is marked by status 1024. During the test BC values
will be calculated assuming there is 5 LPM air flow. After the test a report is generated:
Stability test report.
Serialnumber: AE33-S02-00232
Date and time: 02 Dec 2014 11:46:03
Duration: 00:20:00, Timebase: 1 sec, Flow: 0 mlpm
AverageBC PPBC (ng/m3)
Spot1 Spot2 Spot1 Spot2
Ch1 -13 -4 261 645
Ch2 -5 -3 357 934
Ch3 -3 8 365 899
Ch4 0 16 348 956
Ch5 -2 11 369 1023
Ch6 -23 -29 402 1118
Ch7 -16 -24 473 1230
Result of stability test is acceptable.
Interpretation of the results:
- Average BC values should be close to zero if the Aethalometer is warmed up (was
measuring for a few hours just before conducting the test).
- Point to point variation of BC (PPBC) is calculated as an average absolute difference
between the consecutive BC measurements. It depends on the timebase, tested channel
and spot. A test criterion for 1 s time-base test is: PPBC61 < 450 ng/m
3
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