21
51-638 Echotel Model 338 Two-Wire Ultrasonic Transmitter
1.6.5 Open Channel Flow Configuration
P40
Primary flow elements, formulas,
and data
Factory default value for P40 is: 00
Open channel flow measurement is accomplished by enter-
ing the type of primary flow element being used in P40,
and the flume or weir dimensions in P41 though P45.
NOTE: P40 = 00 to P40 = 08 are not used for open channel flow
applications.
P41 – 45
Flume/weir dimensions
Factory default values for P41 – 45 are: 00
Enter the appropriate dimensions into P41 through P45
depending on which type of primary flow element is
being used.
P40
Primary element (Flume/Weir)
Also set:
09
Parshall flume (for any size Parshall flume)
P46, P42
10
Palmer-Bowlus flume (D/2)
P46, P41
11
Palmer-Bowlus flume (D/3)
P46, P41
12
Palmer-Bowlus flume (rectangular)
P46, P41, P42
13
Khafagi Venturi flume
P46, P42
14
Bottom-step weir
P46, P42
15
Rectangular weir without end contractions (suppressed)
P46, P41, P42
16
Trapezoidal weir
P46, P41, P42
17
Cipolletti trapezoidal (4:1) weir
P46, P42
18
V-notch weir (angle degrees entered in P42)
P46, P42
19
90° V-notch weir
P46
20
Circular weir
P46, P41
21
General flow formula: Q[l/s] = 1000*P41*h
P42
, h [m]
P46, P41, P42
