40
10 Applications and functions
VEGAMET 342 • 4 … 20 mA
63731-EN-221107
Note:
The number of the last switched-on relay is not saved in case of
voltage loss, this means that after the controller is switched back on
again, the relay with the shortest running time always starts first.
10.3 Screen control
In the mechanical pre-cleaning of a hydropower plant, floating solids
are removed with screens or sieves. The subsequent process stages
are thus protected from sedimentation, clogging or abrasion. Large
solids are screened out in the coarse screen, compressed in the
screening press and then disposed of. The fine screen removes the
smaller residues from the waste water. The differential measurement
of the water level in front of and behind the screen determines the de-
gree of pollution and initiates the cleaning of the screen. Two sensors
can be connected simultaneously to the two-channel controller and
the differential measurement can be easily adjusted. Relay outputs
can be used for calculation control and several current outputs for
signal processing.
1
2
4
3
5
6
Fig. 20: Example of a screen control
1 VEGAMET 342
2 Radar sensor 1
3 Radar sensor 2
4 Screen
5 Upstream water
6 Tailwater
10.3.1 Setup
An application wizard guides you through the most common selection
possibilities. Further application options are available on the corre-
sponding DTM/app pages. A more detailed description of all available
application options is included in the DTM online help.
The following steps must be carried out in the application wizard:
Application
