1 Publication 20D-UM002C-EN-P - November 2003
Chapter
10
Communicating with Devices on a
DH-485 Link
Using This Chapter
The DH-485 protocol uses RS-485 half-duplex as its physical interface.
(RS-485 is a definition of electrical characteristics; it is not a protocol.) You can
configure the RS-232 port of the DriveLogix controller to act as an DH-485
interface.
Configuring Your System for
a DH-485 Link
For the DriveLogix controller to operate on a DH-485 network, you need:
• a 1761-NET-AIC converter for each DriveLogix controller you want to
put on the DH-485 network.
• RSLogix 5000 programming software to configure the serial port of the
controller for DH-485 communications
Step 1: Configure the hardware
The RS-232 port on the front of the DriveLogix controller supports the
requirements you need for the DH-485 network connection.
Connect the controller to an RS-232-to-RS-485 isolator. One possible isolator
is the 1761-NET-AIC interface converter. Refer to Access Procedures on
For information about: See page
Configuring your system for a DH-485 link 10-1
Planning a DH-485 network 10-4
Installing a DH-485 network 10-6
Example 1: DriveLogix controller, ControlLogix controller, and SLC
controller on the same DH-485 network
10-9
IMPORTANT
A DH-485 network consists of multiple cable segments.
Limit the total length of all the segments to 1219m
(4000 ft.).
