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1: Inverter; 2: Pump; 3: Check valve; 4: Pressure tank; 5: Valve; 6: Valve; 7: Pressure sensor
11.2. Variable speed pumping group with two or more pumps in
COMBO.
The group consists of two or more pumps (up to 8) each controlled by an inverter, and each equipped
with its own pressure sensor. The inverters are connected to each other via RS485 serial line.
One inverter is configured as master (address 00) while the other inverters are configured as slaves
(addresses 01 to 07).
NOTE
Each inverter must be equipped with its own pressure sensor.
11.2.1. Principle of cascade operation.
Cascade operation is the default operation in COMBO mode.
When there is a water demand, a pump is started at variable speed according to the demand.
As the demand increases and the maximum frequency is reached, a second pump is started.
An additional water demand, leads to an increase in the pump frequency until, having reached its maxi-
mum frequency, a third pump is started and so on.
In case of reduced demand, the last pump started decreases its frequency until it switches off.
11.2.2. Synchronous operating principle.
If the parameter COMBO synchrony is set to ON , synchronous operation is realized. This mode of op-
eration provides additional energy savings over cascade operation.
When there is water demand, a pump is started at variable speed according to the demand.
When the demand increases and the maximum frequency is reached, a second pump is started and the
two pumps run at the same speed to satisfy the water demand.
A further request leads to an increase in the frequency of the two pumps until, having reached their
maximum frequency, a third pump is started and so on.
PSDrive
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