CiDRA SONARtrac PW VF-100 - Manual (Page 165)

20834-01 Rev 04 Page 8-21
8.3.8.6.5 Filter Mode 2
While in Filter Mode 2 the device stores the present and the previous
Percent Length -1 good quality measurements and finds the
minimum and maximum of these points. The device exits Filter Mode
2 and re-enters Normal Mode if the difference between the minimum
and maximum of these points is less then [(Percent/100) x
Measurement Range]. Otherwise the device continues to hold. Filter
Mode 2 exits to Filter Mode 1 if any new measurement has a bad
quality. Filter Mode 2 also has a give up point where instead of re-
entering the No Flow Condition the device will re-enter Normal Mode.
This point is reached if the device has been holding the same
measurement for Percent Length*2 new measurements. In this
example, Filter Mode 2 exits and re-enters Normal Mode if the
difference between the maximum and the minimum of the present
measurement and the previous 2 (Percent Length-1) measurements
is less than 5.4 ft/s (20%/100 * 27ft/s: (Percent/100*Measurement
Range)). Also in this example, the same transition occurs if the
device has been holding the same measurement for 6 (Percent
Length*2) measurements. In each case the measurement at the
transition point will be displayed.