Rockwell Automation 2708-DH5B2L_DH5B4L Attended Workstation - Manual (Page 18)

Chapter 2
Installing a Network
2–5
Installing the Connector
There are two types of connections using the Network Connector. These are
a Master connection and a Non-Master connection. These connections are
shown on Figure 2.7. The physical network connector is shown on Figure
2.4. An examination of both figures shows that there are four open sockets in
which to place three wires; the network plus (+), the network (–), and the
shield wires. In the Network Connector, the three wires connecting the
terminal block to the pins in the DB-9 connector are color coded. This is
consistent with all Network Connectors. It is advised the cable be
color-coded to match the Network Connector to avoid confusion.
Master Connection
The network (–) wire is placed in the connector socket for pin 5 of the
network connector. The network (+) wire is placed in the connector socket
for pin 4 of the network connector. The shield or drain wire is placed in the
connector socket for pin 8 and is the ground connection.
The shield wire is placed in the blue connector socket ONLY in a MASTER
or SUB-MASTER connection. This will effectively ground the network
cable at the MASTER only, and eliminate ground loop current problems.
Figure 2.7
Schematic of the RS-485 Network Using the Network Connector
Network Connector (Catalog No. 2708-NNC)
Master Workstation Normal Workstation Normal Workstation
To Other
Workstations
Shield or
Drain
Wire
Net (+) Net (–)
Simple Network (cont’d)