Allen-Bradley ControlLogix 1756-DH485, User Manual, Page: 33 / 110

1 Publication 1756-UM532A-EN-P - May 2006
Chapter
3
Use Data Highway 485 Network
Introduction
This chapter describes the basics of the Data Highway 485 system and the
operation of a DH-485 network.
What Is Data Highway 485?
On the most basic level, Data Highway 485 is a wire or cable and a protocol
that connects computers and peripheral devices so that they can communicate.
The wire used for a network is called the network medium.
A DH-485 link transfers data between ControlLogix controllers, SLC
controllers, and other devices that use the DH-485 network. These devices are
called stations. You can connect a maximum of 32 stations to a single DH-485
link.
For See
What Is Data Highway 485? 3-1
Two Methods of Communication Over a DH-485 Network 3-2
Use DH-485 Messaging 3-3
Configuration Information in DH-485 Messaging 3-11
Application Timeout 3-12
Example DH-485 Network Routing Configuration 3-13
Use the Common Industrial Protocol (CIP) Messaging 3-14