56 • vacon
INSTALLATION INSTRUCTIONS
8.2 Control unit
The control unit of the frequency converter consists roughly of the control board and additional boards (see
Figure 8-1 and Figure 8-2) connected to the five
slot connectors
(A to E) of the control board. The control
board is connected to the power unit through a D-connector (1) or fibre optic cables.
Figure 8-1. NX control board
Figure 8-2. Basic and option board connections
on the control board
Usually, when the frequency converter is delivered from the factory, the control unit includes at least the
standard compilation of two basic boards (I/O board and relay board) which are normally installed in slots
A and B. On the next pages you will find the arrangement of the
control I/O and the relay terminals
of the
two basic boards, the
and the
. The I/O boards mounted
at the factory are indicated in the type code. For more information on the option boards, see Vacon NX
option board manual (ud741).
The control board can be powered externally (+24V, ±10%) by connecting the external power source to
either of the bidirectional terminala #6 or #12, see page 59. This voltage is sufficient for parameter setting
and for keeping the fieldbus active.
Note! Each AFE module of a NXC regenerative low-harmonic drive has its own control unit. The three
basic boards A1,A2 and B5 are included as standard. AFE control usually needs to be parameterized
only once during the commissioning of the drive.
Note! If the 24V inputs of several frequency converters are parallelly connected we recommend to use a
diode in terminal #6 (or #12) in order to avoid the current to flow in opposite direction. This might damage
the control board. See picture below.
A
B
C
D
E
+
-
#6
#7
+
-
#6
#7
+
-
#6
#7
+
-
#6
#7
nk6_17
External
+24V
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