MAGEE Scientific Aethalometer AE33 User Manual page 48

Aethalometer
Model AE33
Valve status
Sigma_Air
LED err
Detector err
ATNf1 and
ATNf2
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User's manual – Ver. 1.55
330 and 410 indicate "Chamber tape" and between 455 and
465 indicate "Chamber calibrate" position.
Valve status shows valve on/off status for the 4 valves. See
chapter 5.3 Flow Diagram.
Sigma_Air is the column with mass absorption cross-section
for the 7 channels (see 5.1 Basic calculations for details).
These values are exported in the setup file.
If during Led calibration procedure an overcurrent is
detected on any channel the LED status will switch to 1 (LED
OVERCURRENT) on that channel.
If during Led calibration procedure the +24V fuse fails the
LED status will switch to 128 (+24V FUSE ERROR) on all
channels.
During LED calibration all Detector Error statuses will switch
to 10 (LED NOT CALIBRATED). When any channel is
calibrated successfully its Detector Error status will switch to
0 (CALIBRATION OK). If there is a calibration error on any
channel the Error status will switch to 11 (CALIBRATION
ERROR) on that channel.
ATNf1 and ATNf2 determine the ATN range used to calculate
the face velocity ratio factor (FVRF). FVRF is introduced in the
calculation of the k parameter as an additional empirical
factor to help eliminate errors due to flow determination. It is
determined as an intercept of the ratio ATN2/ATN1 vs. ATN1
for data fitted with the linear function within a certain
attenuation range between the values ATNf 1 = 10 and ATNf 2
July 2017 48/146