Rockwell Automation 1763 MicroLogix 1100 Programmable Controllers User Manual - Manual (Page 211)

Publication 1763-UM001D-EN-P - March 2011
Connecting to Networks via RS-232/RS-485 Interface 209
lowest numbered addresses to minimize the time required to initialize the
network. The valid range for the MicroLogix™ controllers is 1...31 (controllers
cannot be node 0). The default setting is 1. The node address is stored in the
controller Communications Status file (CS0:5/0 to CS0:5/7).
Setting Controller Baud Rate
The best network performance occurs at the highest baud rate, which is
19,200. This is the default baud rate for a MicroLogix™ device on the DH-485
network. All devices must be at the same baud rate. This rate is stored in the
controller Communications Status file (CS0:5/8 to CS0:5/15).
Setting Maximum Node Address
Once you have an established network set up and are confident that you will
not be adding more devices, you may enhance performance by adjusting the
maximum node address of your controllers. It should be set to the highest
node address being used.
MicroLogix Remote Packet Support
MicroLogix™ controllers can respond and initiate with communications (or
commands) that do not originate on the local DH-485 network. This is useful
in installations where communication is needed between DH-485 and DH+
networks.
The example below shows how to send messages from a device on the DH+
network to a MicroLogix controller on the DH-485 network. This method
uses an SLC 5/04 processor as the bridge connection.
When using this method (as shown in the illustration below):
• PLC-5 devices can send read and write commands to MicroLogix™
controllers.
• MicroLogix™ controllers can respond to MSG instructions received.
• The MicroLogix™ controllers can initiate MSG instructions to devices
on the DH+ network.
• PC can send read and write commands to MicroLogix™ controllers.
• PC can do remote programming of MicroLogix™ controllers.
IMPORTANT
All devices should be set to the same maximum node
address.