17
4 Mounting
VEGAPULS C 21 • Modbus and Levelmaster protocol
58343-EN-200806
•
Mounting the sensor on the upstream or inlet side
•
Installationinthecentreoftheumeandverticaltotheliquid
surface
•
DistancetotheoverfalloriceorVenturiume
•
Min. distance to the max. height of damming for optimum accu-
racy: 250 mm (9.843 in)
2)
Detailed project planning data can be found at the channel manufac-
turers and in the technical literature.
Thefollowingexamplesserveasanoverviewforowmeasurement.
3 ... 4 h
max
90°
2
3
1
h
max
≥ 2 x h
max
90°
42 3
≥ 250 mm
(
9.84")
≥ 250 mm
(
9.84")
Fig.16:Flowmeasurementwithrectangularume:h
max.
=max.llingofthe
rectangularume
1 Overfallorice(sideview)
2 Upstream water
3 Tailwater
4 Overfallorice(viewfromtailwater)
Rectangular overfall
2)
At smaller distances the measuring accuracy is reduced, see "Technical
data".