27
If two pumps are connected in parallel, the first driven by DrivE-Tech and the second with a DOL
connection, it is necessary makes sure that the value “delta control” will be sufficiently high to ensure
the first pump, once the DOL pump is switched on, will reach a frequency higher than its minimum
frequency value.
By proper setting of the minimum frequency, excessive pump ON/OFF cycling is avoided, thus
preventing damage to the DOL pump.
8.2 COMBO function
In the “Installer parameters” menu it is possible to enable the COMBO function that allows serial communication between up
to 8 DrivE-Techs, each one connected to a pump. The operating principle (switch on/off) of pumps is similar to as stated in
chapter 8.1.
To achieve the COMBO function in a system consisting of several interconnected DrivE-Techs, use a pressure sensor
connected to each DrivE-Tech. The value of the
set pressure
is communicated to the slaves via the serial port.
To prevent the shutdown of the system due to pressure sensor failure, connecting a 2nd pressure sensor to the DrivE-
Tech; make sure that the two pressure sensors are identical.
Remember to perform the offset operation of the sensors in each DrivE-Tech (Installer Parameters menu) .
C1
C2
P2
P1@f min Q=0
P1+P2
Q
H
