Appendix D; Multidrop Communications; Multidrop Addresses - Allen-Bradley 2755-LS7-SB User Manual

Multidrop Addresses

Multidrop Communications

This appendix describes the rules for setting up a concentrator or
controller to communicate with a reader in standard Multidrop
protocol.
Multidrop networks allow you to connect up to 50 readers to a single
host via a concentrator or controller. Be aware of the following
when setting up for multidrop communication.
•
No two readers in the multidrop network can have the same
address.
•
Each reader in the network must have an address (from 1 to 50)
assigned in its configuration program.
•
Each address has its own separate poll and select address (from
1C to 7F hex).
Refer to the table on page D–2 for the poll and select addresses.
Host
Concentrator
or Controller
Appendix
Polled Protocol
Multidrop Only
RS-485 Interface
(LAN)
reader
reader
reader
Publication 2755-6.9
D