Dynasonics DDFXD Doppler Ultrasonic Flow Meter - Manual (Page 41)

06-DPP-UM-00147 02/12 41
FLUID SPECIFIC GRAVITY
SP GRAV -- Fluid Specific Gravity (Value)
Unitless Value
Allows adjustments to be made to the specific gravity (density relative to water) of the liquid.
If Pounds (LBS) or Kilograms (KGS) is selected for either the RATE UNT or the TOTL UNT, a specific gravity
must be entered for the correct mass flow to be calculated. A list of fluids and their associated specific
gravities is located in the Appendix of this manual.
NOTE: Specific Gravity only appears when LBS or KGS are selected in either Rate Unit or Total Unit
LOW FLOW CUT-OFF
F C-OFF -- Low Flow Cut-off (Value)
Unitless Value
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. The value entered is in actual rate units.
SCALE FACTOR
SCALE F -- Scale Factor (Value)
0.500 to 5.000
This function can be used to make the DFX system agree with a different of reference flow meter, or to
compensate for an installation where there is inadequate straight pipe to obtain a laminar flow pro-
file, by applying a correction factor/multiplier to the readings and outputs. A factory calibrated system
should be set to 1.000. The range of settings for this entry is 0.5000 to 5.000. The following example
describes using the SCALE F entry.
The DFX meter is indicating a flow rate that is 4% higher than another flow meter located in the
same pipe line. To make the DFX indicate the same flow rate as the other meter, enter a SCALE F
of 0.960, to lower the readings by 4%.
SYSTEM DAMPING
DAMPING -- System Damping (Value)
Relative Percent Entry: 0-99%
Flow Filter Damping establishes a maximum adaptive filter value. Under stable flow conditions (flow var-
ies 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 and allows the meter to react faster. Increasing this value tends to provide
smoother steady-state flow readings and outputs.