ABB NETA-21 Installation And Startup Manual page 9

Data link connections –
Drive (/converter/inverter) with the RDCU control unit
The figure below shows the data connections in a ring topology when a fiber optic link
is used.
PC
Connect the NETA-21 primarily to fiber optic channel ch3 on the RDCO connector
unit. You can connect the NETA-21 also to ch0 if the maximum speed of the DDCS
communication does not increase above 1 Mbit/s.
The default the NETA-21 settings for a DDCS network are ring topology and 1 Mbit/s
communication speed. With these settings, the NETA-21 can normally auto-detect
drives (/converters/inverters) connected to an NDBU branching unit. The NETA-21
auto-detects connected devices when the fiber is connected for the first time. If
reconfiguration is needed afterwards, it can be done in the web user interface.
If the DDCS communication speed is higher than 1 Mbit/s, the NETA-21 settings and
device interfaces must have the same speed settings as the NDBU unit.
NETA-21
PC
ETH1
Tx
ETH2
Rx
Link to Ethernet networks
NETA-21 remote monitoring tool 9
ABB drive, ABB drive,
converter or converter or
inverter inverter
RDCU RDCU
RDCO RDCO
T R T
T
Drive/converter/inverter 1 first in the ring,
drive/converter/inverter 10 last in the ring
ABB drive,
converter or
inverter
RDCU
RDCO
R T R
T