Operating Modes; Capacity Control Of The Compressor Depending On An External Setpoint Signal - Bitzer VARIPACK FD+6 Instructions De Service

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.
f [Hz]
0 .. 10 V
f
max
f
min
0 0 2 4
Fig. 12: "Min .. Max" control characteristic
20
6 8 10
U [V]
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.
f [Hz]
4 .. 20 mA
f
max
f
min
0 4
12
8 12 16
I [mA]
CB-100-2
20