Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 25)

Publication AG-UM008C-EN-P - February 2005
Designing Communication 1-7
SLC 500 Processors with a 1747-KE Module Addressing Considerations
Since you can have up to 254 devices on a half-duplex network and
32 devices on a DH-485 network, to allow 255 DH-485 nodes requires
using a group number. This parameter defines the address group of
the SLC 500 half-duplex address. Each address group can consist of 32
addresses.
The slave address of the SLC 500 processor is determined with the
following formula: (32*G)
+ Α
, where G is the group number (0 to 7)
and A is the DH-485 node address of the SLC 500 processor.
One station address within each group of size 32 must be reserved for
any 1747-KE modules configured with that group number. A second
address within each group should also be reserved for local DH-485
programming terminals. These 16 addresses (two per group) should
never have to be polled by the master station.
ATTENTION
Do not use slave addresses contained within a KE
group. When nodes are added to respective DH-485
networks, there is a possibility of duplicate nodes.