ABB ACA 6 Series - NIOC Board Chaining

Chapter 3 – Electrical Installation
ACA 6xx Sections and ACS/ACC 6x7 (132 to 3000 kW) Frequency Converters 3-33
NIOC Board Chaining
When several NIOC boards are daisy-chained for common control from
an external Modbus device the bus termination switch (SW1) must be
set on the participating boards as shown below.
Note: This chaining is not supported by System Application Program.
Settings of
Switch SW1
Function
Termination OFF
Termination ON (default)
OFF
OFF
ON
. . .
. . .
NAMC
NIOC
on
off
NIOC
No 1
SW1
ON
NIOC
No 2
SW1
OFF
NIOC
No 3
SW1
OFF
NIOC
No 4
SW1
ON
Drive units at a common earth potential (e.g. installed in the same cabinet)
Note: When drive units are not at a common earth potential, or long
distance (> 3 m) connection is required, NBCI modules can be used. Refer
to the module manual.
X28
X29
Straight-through cable (Ident.: Grey)
(pin 1 to pin 1, pin 2 to pin 2, etc.)
RS 485
Modbus
This board should have
SW1 in the OFF position if
the external Modbus device
has a bus termination
circuit. If in doubt, set SW1
to ON here.