Dynasonics TFXP Series Transit Time Ultrasonic Flow Meter - Manual (Page 54)

Rev. 5/09
-3.16- TFXP
MAX RATE -- Maximum Flow Rate Settings (Value)
Rate Unit/Rate Interval
A maximum volumetric flow rate setting is entered to establish filter
software settings. Volumetric entries will be in the Engineering Rate
Units and Interval selected on pages 3.13 and 3.14. Set Max Rate
to the highest (positive) flow rate expected in the piping system.
FL C-OFF -- Low Flow Cut-off (Value)
Percent of the range between MIN RATE and MAX RATE
Relative Percent Entry: 0-100%
A Low Flow Cut-off entry is provided to allow very low flow rates
(that can be present when pumps are off and valves are closed) to
be displayed as zero flow. Typical values that should be entered
are between 1.0% and 5.0% of the flow range between Min Rate
and Max Rate.
Generally a Low Flow Cutoff value that equates to a velocity of 0.5
fps is a good starting point. For example, using a 4" pipe and a
maximum flow of 500 GPM, the volumetric flow at 0.5 fps is about
20 GPM. 20 GPM is 4% of the 500 GPM maximum so the Low
Flow Cutoff should be set to 4.
DAMP PER -- System Damping (Value)
Relative Percent Entry: 0-100%
Flow Filter Damping establishes a maximum adaptive filter value.
Under stable flow conditions (flow varies less than 10% of reading),
this adaptive filter will increase the number of successive flow
readings that are averaged together up to this maximum value. If
flow changes outside of the 10% window, the flow filter adapts by
decreasing successive flow readings and allows the meter to react
faster. Increasing this value tends to provide smoother steady-state
flow readings and outputs. If erratic flow conditions are present or
expected, more advanced filters are available for use in the
ULTRALINK™ software utility. See Part 4 for further information.
System
Damping
Low Flow
Cut-off
Maximum
Flow Rate
PART 3 - KEYPAD CONFIGURATION