Vega VEGAMET 841, Руководство по эксплуатации

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10 Applications and functions
VEGAMET 841 • 4 … 20 mA
58864-EN-200401
The pump control system offers the possibility to choose between
sequenced and alternating pump operation:
•
Sequenced operation: Depending on the switching points, all
pumps are switched on one after the other, i.e. the max. number
of pumps that can be switched on corresponds to the number of
assigned relays
•
Alternating pump operation: Independent of the switching point,
only one pump at a time is switched on
If the level does not change over a longer period of time, the same
pump would remain switched on. Via the parameter " Changeover
time ", a time period can be preset, after which a forced changeover of
the pump is carried out. This function is described under pump control
1/2.
If all pumps have the same capacity and are used for the same task
alternately, the running time should always be roughly the same. The
respective operating hours are summed up individually in the control-
ler and can be read out in the menu " Diagnosis – Status - Relay ". If
a large difference between the pumps is determined, the capacity of
one of the pumps must have fallen considerably. This information can
be consulted for diagnosis and service, e.g. to recognize plugged-up
filters or worn out bearings.
Since in this case all pumps operate alternately in the same area,
their switch-on and switch-off points must be the same. In addition,
the mode " Alternating pump operation " must be active.
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 Flow measurement flume/weir
Waste water and rainwater are often transported to the sewage treat-
ment plant in open collection channels. The flow rate is measured at
various points in the collection channels. For flow measurement in
open waters, a constriction or a standardised channel must be used.
This constriction creates a certain backwater depending on the flow
rate. The flow rate can now be derived from the level of this backwater.
The current flow rate is shown on the display in the selected unit of
measurement (e.g. m
3
/h). In addition, the flow rate is made available
via the current output and can thus be further processed by down-
stream devices.
It is also possible to totalize the flow rate by means of a totalizer, the
result is shown on the display (e.g. in m
3
). In addition, the flow rate can
be output via a corresponding number of pulses on the relay/current
output (flow rate pulse). A sampling pulse can also be configured.
Pump control mode
Option, forced switchover
Diagnosis via running
time
Application