Nastec ANDO VASCO - Electrical Connections; Programming; Variable Speed Pumping Unit with Two or more Pumps in COMBO Mode; Cascade Operating Principle

The primary pump continues its operation at variable speed according to the instantaneous water demand.
In case of reduced demand, the primary pump decreases its frequency and the inverter progressively switches off
the D.O.L pump 2 and the D.O.L pump 1.
If parameter Alternance is set to ON, the D.O.L. pumps are started with alternating priority.
11.2.2. Electrical connections.
NO4 COM4 NC4
DOL 2
INVERTER
NO3 COM3 NC3
DOL 1
PILOT 1
0V IN1
DIG. INPUT
PILOT 2
0V IN1
DIG. INPUT
DIG. INPUT 1 = N.C.
11.2.3. Programming.
Menu Parameter Value
Control. param. Pump DOL 1 ON to activate / OFF to deactivate
Control. param. Pump DOL 2 ON to activate / OFF to deactivate
Control. param. Alternance ON to activate / OFF to deactivate
Control. param. Start delay AUX In order to avoid cyclic switching on and off of the D.O.L. pumps, it is advisable to set
it to at least 1 s.
Control. param. Delta control In order to avoid cyclic switching on and off of the D.O.L. pumps, it is advisable to
set a sufficiently high value so that, when the D.O.L. pump switches on, the variable
speed pump will run at a higher frequency than its minimum frequency at zero flow.
Control. param. Delta stop In order to avoid cyclic switching on and off of the D.O.L. pumps, it is advisable to
set a sufficiently high value so that, when the D.O.L. pump switches on, the pressure
does not rise above such value.
11.3. Variable speed pumping unit with two or more pumps in COMBO
mode.
The unit 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 port.
One inverter is configured as master (address 00) whereas the others are configured as slaves (addresses 01 to
07).
NOTE
Each inverter must be equipped with its own pressure sensor.
11.3.1. Cascade operating principle.
Cascade operation is the default operation in COMBO mode.
When water is required, 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 maximum
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.
VASCO - VAriable Speed COntroller
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