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11 Applications and functions
VEGAMET 861 • 4 … 20 mA/HART
58866-EN-200401
There is also the possibility of using multiple large pumps in alternat-
ing mode. The algorithm for the switching function is then determined
by the pump control mode.
Fig. 19: Example of a pump control with option "Dry weather pump"
Note:
If the option "
Dry weather pump
" is activated, only the mode "
Alternat-
ing 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 has not changed over a longer period, the same pump
would always remain switched on. Via the parameter "
Switchover
time
", a time can be preset which, after it is elapsed, forces a switcho-
ver of the pump. Which pump is switched on depends on the selected
pump mode. If all pumps are already switched on, the pump remains
switched on.
Note:
If the pump is already switched on when the forced switchover is
activated, the timer is not started. Only after the pump is switched off
and on again will the timer start. If a switch-off delay is set, it will not
be taken into account, i.e. the switchover is carried out exactly after
the preset time for the forced switchover expires. A preset switch-on
delay, however, is taken into account, i.e. the forced switchover to
Pump control mode
Option, forced switchover
