Nc: Simultaneous Inverters; Ic: Reserve Configuration; Examples Of Configuration For Multi-Inverter Systems; Et: Exchange Time - DAB ACTIVE DRIVER PLUS M/T 1.0 Installations- Und Wartungsanleitungen

6.6.8.2 NC: Simultaneous inverters

This sets the maximum number of inverters that can operate simultaneously.
It can be set with a value from 1 to NA. By default NC is set with the value NA; this means that whatever increase
applied to NA, NC is always set with the value of NA. If a different value from NA is set, the system sets to the set
maximum number of simultaneous inverters. This parameter is used when there is a limited number of pumps to be
kept in operation (see IC: Configurazione della riserva section 6.6.8.3 and the following examples).
In the same menu page, the user can view (without the option of modification) a further two system parameters related
to this value, i.e. N, the number of inverters detected automatically by the system, and NA, the number of active
inverters.

6.6.8.3 IC: Reserve configuration

This configures the inverter as automatic or reserve. If set to auto (default) the inverter participates in the normal
pumping process; if configured as reserve, it is assigned with minimum start-up priority, i.e. this inverter will be the last
to start up. If the number of active inverters setting is lower of one unit than the number of inverters present and one
element is set as reserve, this means that in normal operating conditions the reserve inverter does not participate in
normal pumping operations; otherwise if there is a fault on one of the active inverters, (power supply failure, safety
device trip etc.) the reserve inverter is started up.
The reserve configuration status can be checked as follows: in the SM page, the upper section of the icon is coloured;
in the AD and main pages, the communication icon representing the inverter address is displayed with the number on
a coloured background. There may be more than one inverter configured as reserve in a pumping system.
Inverters configured as reserve, even though not part of the normal pumping process, are still kept efficient by means
of the anti-stagnant algorithm. The anti-stagnant algorithm envisages, once every 23 hours, the exchange of start-up
priority, to ensure that each inverter accumulates at least one minute of continuous flow. This algorithm aims at
avoiding deterioration of the water in the impeller and to maintain efficiency of moving parts; it is useful for all inverters
and in particular for the inverters configured as reserve, which do not operate in normal conditions.

6.6.8.4 Examples of configuration for multi-inverter systems

Example 1:
A pump set comprising 2 inverters (N=2 detected automatically) of which 1 is set as active (NA=1), one simultaneous
(NC=1 or NC=NA provided that NA=1) and one as reserve (IC=reserve on one of the two inverters).
The effect is as follows: the inverter not configured as reserve starts up and runs alone (even if it cannot withstand the
hydraulic load and the pressure is too low). In the event of a fault, the reserve inverter is started up.
Example 2:
A pump set comprising 2 inverters (N=2 detected automatically) of which all inverters are active and simultaneous
(default setting NA=N and NC=NA) and one as reserve (IC=reserve on one of the two inverters).
The effect is as follows: the inverter not configured as reserve always starts up first; if the pressure reached is too low,
the second inverter, configured as reserve, also starts up. In this way, the use of one inverter in particular is preserved
(the inverter configured as reserve), but is always available as a support when necessary in the event of increased
hydraulic loads.
Example 3:
A pump set comprising 6 inverters (N=6 detected automatically) of which 4 are set as active (NA=4), 3 simultaneous
(NC=3) and 2 as reserve (IC=reserve on two inverters).
The effect is as follows: a maximum of 3 inverters start up simultaneously. Operation of the 3 inverters enabled for
simultaneous mode is implemented in rotation between the 4 inverters to remain within the maximum operating time of
each ET. In the event of a fault on one of the active inverters, no reserve unit is started up as no more than three
inverters can be started up at a time (NC=3) and there are still three active inverters present. The first reserve unit
intervenes only when one of the remaining three has a fault; the second reserve is started up when another of the
three (including the first reserve) has a fault.

6.6.9 ET: Exchange time

This sets the maximum continuous operating time of an inverter within a group. It is only applicable on pump sets with
interconnected inverters (link). The time can be set to between 10 s and 9 hours, or to 0; the factory setting is 2 hours.
When the value is modified, the parameter symbol starts to blink, indicating that the value has changed. The
modification will be effective only when [SET] or [MODE] is pressed or when the menu is changed. If you do not press
any key after having changed the parameter and leave the page by timeout, the change will not be effective.
When the time ET of an inverter has elapsed, the system starting order is re-assigned so that the "expired" inverter is
set to minimum priority. This strategy aims at reducing use of the inverter that has already been in operation, and to
balance operating times of the various units in the group. Despite assignment as the last unit in the starting order, if
the hydraulic load requires intervention of this specific inverter, it is started up to guarantee adequate system
pressure.
The starting priority is re-assigned in two conditions, according to the time ET:
1) Exchange during pumping process: when the pump is active continuously through to exceeding the maximum
absolute pumping time.
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