Bitzer VARIPACK FDU+6 - Operating Modes; Capacity Control of the Compressor Depending on an External Setpoint Signal

CB-100-220
5.4 Operating modes
The VARIPACK frequency inverter can be operated in
two different operating modes:
• Capacity control of the compressor depending on an
external setpoint signal (see chapter Capacity con-
trol of the compressor depending on an external set-
point signal, page 20).
• Capacity control of the compressor depending on the
evaporation pressure, which will require the optional
extension module for pressure control (see chapter
Capacity control of the compressor as a function of
the evaporation pressure, page 21).
In addition to direct evaporation pressure control, the
condenser fan can also be controlled via a 0..10V
output signal and a second compressor can be connec-
ted.
5.4.1 Capacity control of the compressor depending
on an external setpoint signal
"Min..Max" control characteristic
The VARIPACK frequency inverters can be activated
without change in parameters by a0..10V or
4..20mA signal according to the "Min..Max" control
characteristic.
• In the "Min..Max" control characteristic, the com-
pressor will start as soon as the DI1 (X13: 2) start
command is given. The setpoint signal will control
the frequency linearly between the minimum and
maximum frequencies of the compressor.
– If a 0..10V signal is used, it must be connected
to the input AI2 (X11:2).
– If a 4..20mA signal is used, it must be connec-
ted to the input AI1 (X11:1).
Graphical explanation of the "Min..Max" control char-
acteristic, see figure 12, page 20.
0
f [Hz]
I [mA]
4 8 12 16 20
4 .. 20 mA
f [Hz]
0 2 4 6 8 10 12
0
U [V]
0 .. 10 V
f
max
f
min
f
max
f
min
Fig.12: "Min..Max" control characteristic