39
10 Applications and functions
VEGAMET 341 • 4 … 20 mA
63730-EN-210616
Fig. 18: Example of a pump control with option " Dry weather pump"
Note:
If the option "
Dry weather pump
" is activated, only the mode "
Alter-
nating pump operation
" will be available, i.e. only one pump at a time
is in operation.
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.
Pump control mode
Option, forced switchover
Diagnosis via running
time
