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57-606 ECLIPSE Model 706 Guided Wave Radar Transmitter
3.4.5.2 Configuration using Generic Equation
The following table provides an explanation of each of the
System Configuration parameters for Open channel flow
applications using the Generic Equation.
Configuration Parameter Explanation (Open Channel Flow — using the Generic Equation)
Flow Units
A selection of Gallons/Minute (factory default ), Gallons/Hour,
Mil Gallons/Day, Liters/Second, Liters/Minute, Liters/Hour, Cubic Meter/Hour,
Cubic Ft/Second, Cubic Ft/Minute, and Cubic Ft/Hour are provided.
Flow Element
Select one of the following primary that are stored in the firmware:
Parshall flume sizes of 1", 2", 3", 6", 9", 12", 18", 24", 36", 48", 60", 72", 96",
120" and 144". Palmer-Bwls (Palmer-Bowlus) flume sizes of 4", 6", 8", 10", 12",
15", 18", 21", 24", 27" and 30". V-notch weir sizes of 22.5
O
, 30
O
, 45
O
, 60
O
, 90
O
and
120
O
. Rect with Ends (Rectangular Weir with End Contractions), Rect w/o Ends
(Rectangular Weir without End Contractions), and Cipoletti weir. Custom Table (see
page 65 can be selected if none of the stored can be used. The
table can be built with a maximum of 30 points. The Model 706 also has the capa-
bility of using a Generic Equation (see page 26) for flow calculation.
Generic Eqn Factors
is a discharge flow equation in the form of Q = K(L-CH)H
n
, where
Q = flow (Cu Ft/Second), H = Head (Feet), K = a constant, and L, C and n are user
input factors that depend on which is being used. Make sure the flow
equation is in the form of Q = K(L-CH)H
n
, and proceed to enter the values of K,L,C,H
and n. See example below.
NOTE: The Generic Equation parameters must be entered in Cu Ft/Second
units. The resultant flow is converted by the Model 706 into whatever Flow Units
are selected above. See example below.
Reference Dist
The is measured from the sensor reference point to the point
of zero flow in the weir or flume. This must be measured very accurately in the
user-selected level units.
Maximum Head
is the highest liquid level (Head) value in the flume or weir before
the flow equation is no longer valid. The is expressed in the user-
selected level units. The Model 706 will default to the largest value
that is allowed for any given flume or weir. The value can be revised
depending on the value of the , or for end user preference.
Maximum Flow
is a read-only value that represents the flow value corresponding
to the value for the flume or weir.
Low Flow Cutoff
The (in user-selected level units) will force the calculated flow
value to zero whenever the is below this point. This parameter will have a
default and minimum value of zero.
Using the factors above the equation becomes:
Q = 3.33 (8-0.2H) H
1.5
The discharge flow value for a Head value of three feet
becomes 128.04 Cubic Ft/Second. If GPM was selected for
the Flow Units, the Model 706 Measured Values screen would
display this value converted to 57,490 GPM.
Generic Equation Example (using equation for an 8' rectangular weir w/ end contractions)
Q = Cubic Ft/Second flow rate L = 8' (weir crest length in feet) H = Head value
K = 3.33 for Cubic Ft/Second units C = 0.2 (constant) n = 1.5 as an exponent
Q = K(L-CH)H
n
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