CiDRA SONARtrac PW VF-100 - Manual (Page 164)

20834-01 Rev 04 Page 8-20
will display dashes until the 5
th
measurement of 5 consecutive good
quality measurements is made. At this time the 5
th
measurement is
displayed and the device enters Normal Mode.
8.3.8.6.3 Normal Mode
While in Normal Mode the device displays each new measurement
unless one (in order of priority) of the following conditions occurs at
which time it will hold the previously displayed measurement:
1. The new measurement has a bad quality
2. The difference between the maximum and the minimum of the
new measurement and the previous Percent Length-1
measurements is greater than Percent/100 * Measurement
Range
Condition 1) puts the device into Filter Mode 1 which as stated below
forces the display to hold the previously displayed measurement.
Condition 2) puts the device into Filter Mode 2 which also forces the
display to hold the previously displayed measurement.
Note: Filter Mode 1 and Filter Mode 2 can be bypassed by setting
Filter Length = 0 This setting forces the device to operate in either
the No Flow Condition or in Normal Mode, and while in Normal Mode
any bad quality measurement will force the device back into the No
Flow Condition.
8.3.8.6.4 Filter Mode 1
While in Filter Mode 1 the device keeps track of the number of good
quality measurements and bad quality measurements in a counter
called the quality counter. Every time a bad quality measurement is
made Up Count is added to the quality counter and every time a good
quality measurement is made Down Count is subtracted from the
quality counter. This process enables the user to choose the ratio of
good to bad quality measurements required before the device stops
holding a previous measurement and starts displaying new
measurements in Normal Mode. The Filter Length parameter also
provides the user with a give-up point where the device exits Filter
Mode 1 and re-enters the No Flow Condition. In this example the user
requires a ratio of 3:2 (Up Count to Down Count) or 1.5 good quality
measurements for each bad quality measurement before the device
re-enters Normal Mode. Also, the device will give up holding and start
displaying dashes by re-entering the No Flow Condition if 3 (Filter
Length) consecutive bad quality measurements are made or the
above mentioned quality counter exceeds 9 (Filter Length * Up
Count) or the display has held the same value for 7 (Filter Length *
(1 + Up Count/Down Count) ) measurements.