Dynasonics TFXP Series Transit Time Ultrasonic Flow Meter - Manual (Page 86)

Rev. 5/09
-4.8- TFXP
Time Domain Filter adjusts the number of raw data sets (the wave
forms viewed on the ULTRALINK™ Diagnostics Screen) that are
averaged together. Increasing this value will provide greater
damping of the data and slow the response time of the flow meter.
This filter is not adaptive – it is operational to the value set at all
times.
Low Signal Cutoff is a duplicate entry from Flow tab. Adjusting
this value adjusts the value on the Flow tab.
Substitute Flow is a duplicate entry from Flow tab. Adjusting this
value adjusts the value on the Flow tab.
Short Pulse Duration is a function used on pipes larger than 8
inches (200 mm). If the pipe has an outer diameter of 8 inches or
more, make sure that the Auto Short Pulse box is checked. Set
this value to zero to disable the function.
Flow Filter Damping establishes a maximum adaptive filter value.
Under stable flow conditions (flow that varies less than the Flow
Filter Hysteresis entry) this adaptive filter will increase the number
of successive flow readings that are averaged together up to the
maximum value entered in this field. If flow changes outside of the
Flow Filter Hysteresis window, the Flow Filter adapts by
decreasing the number of averaged readings and allows the meter
to react faster. Increasing this value tends to provide smoother
steady-state flow readings and outputs.
Flow Filter Hysteresis creates a window around the average flow
measurement reading whereby if the flow varies within that window,
Flow Filter Damping will increase up to the maximum value
entered in the Flow Filter Damping field. The filter also establishes
a flow rate window where measurements outside of the window are
captured by the Bad Data Rejection Filter. The value is entered as
a percentage of actual flow rate.
Example: If the average flow rate is 100 GPM and the Flow Filter
Hysteresis is set to 5%, a filter window of 95-105 GPM is
established. Successive flow measurements that are measured
within that window are recorded and averaged in accordance with
the Flow Filter Damping setting. Flow readings outside of the
window are held up in accordance with the Bad Data Rejection
Filter.
PART 4 - SOFTWARE UTILITIES