Dynasonics TFXP Series Transit Time Ultrasonic Flow Meter - Manual (Page 87)

Rev. 5/09
-4.9- TFXP
Flow Filter MinHysteresis sets a minimum hysteresis window that
is invoked at sub 0.25 FPS (0.08 MPS) flow rates, where the “of
rate” Flow Filter Hysteresis is very small and ineffective. This entry
is entered in picoseconds and is differential time. If very small fluid
velocities are to be measured, increasing the Flow Filter
MinHysteresis value can increase reading stability.
Flow Filter Sensitivity allows configuration of how fast the Flow
Filter Damping will adapt in the positive direction. Increasing this
value allows greater damping to occur faster than lower values.
Adaptation in the negative direction is not user adjustable.
Bad Data Rejection is a value related to the number of successive
readings that must be measured outside of the Flow Filter
Hysteresis and Flow Filter MinHysteresis windows before the
flow meter will assume the change is actual. Larger values are
entered into the Bad Data Rejection when measuring liquids that
contain gas bubbles, as the gas bubbles tend to disturb the
ultrasonic signals and cause more extraneous flow readings to
occur. Larger Bad Data Rejection values tend to make the flow
meter more sluggish to rapid changes in actual flow rate.
Figure 4.5 — Advanced Tab Layout
PART 4 - SOFTWARE UTILITIES