DAB AD 2.2 AC Instructions Pour L'installation Et La Maintenance page 102

List of parameters with optional alignment:
 LA Language
 RC Rated current
 MS Measurement system
 FS Maximum frequency
 SO Min. dry-running factor threshold
 AE Anti-blocking
 O1 Output 1 function
 O2 Output 2 function
4.4 Initial start-up of multiple inverter system
Make electrical and hydraulic connections of the entire system as described in para 2.2 and para 4.2.
Switch on one inverter at a time and configure the parameters as described in chapter 5 taking care that when
turning on one inverter, all others are switched off.
After configuring all inverters individually, all can be switched on simultaneously.
4.5 Multi-inverter settings
When a multi inverter system is switched on, the addresses are assigned automatically and, by means of an
algorithm, an inverter is nominated as the settings leader. The leader decides on the frequency and order of
start-up of each inverter in the series.
The settings mode is sequential (inverters start one at a time). When start-up conditions are enabled, the first
inverter starts, and when this reaches maximum frequency, the next one starts, and so on. The order of start-
up is not necessarily ascending according to the machine address, but depends on the hours of operation; see
ET: Tempo di scambio par. 6.6.9.
When the minimum frequency FL is used, and there is only one inverter operative pressure surges may occur.
Depending on the case, pressure surges may be inevitable and may occur at the minimum frequency when
this value, in relation to the hydraulic load, causes a pressure level greater than the required value. On multi
inverter systems, this problem remains limited to the first pump that is started up, as on the subsequent pumps
the situation is as follows: when the previous pump reaches the maximum frequency, the next one starts up
at the minimum frequency to then reach the maximum frequency. When the frequency of the pump at maximum
is reduced (obviously through to the minimum frequency limit) the pump activation overlaps, which while
observing minimum frequency rates, does not cause pressure surges.
4.5.1 Assigning the start-up order
Each time the system is activated, each inverter is associated a starting order. This setting establishes the
order of inverter start-up.
The starting order is modified during use according to requirements, by the two following algorithms:

Reaching of maximum operating time

Reaching of maximum inactivity time
4.5.1.1 Maximum operating time
According to parameter ET (maximum operating time), each inverter has an hour counter, and the starting
order is updated on the basis of these values according to the following algorithm:
- if at least half of the value ET is exceeded, priority is changed on the first shutdown of the inverter
(switch to standby).
- if the value ET is reached without stopping, the inverter stops unconditionally and this sets to the
minimum restart priority (switch during operation).
If parameter ET (maximum working time) is set to 0, exchange occurs on each restart.
See ET: Tempo di scambio par 6.6.9.
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