Rockwell Automation 1764-xxxx MICROLOGIX 1500 PROGRAMMABLE CONTROLLERS - Manual (Page 143)

Publication 1764-UM001B-EN-P - April 2002
Understanding Communication Protocols E-11
Setting Node Addresses
The best network performance occurs when node addresses are
assigned in sequential order. Initiators, such as personal computers,
should be assigned the lowest numbered addresses to minimize the
time required to initialize the network. The valid range for the
MicroLogix 1500 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 19200. This is the default baud rate for a MicroLogix 1500 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 1500 controllers can respond and initiate with device’s
communications (or commands) that do not originate on the local
DH-485 network. This is useful in installations where communication
is needed between the DH-485 and DH+ networks.
The example below shows how to send messages from a PLC device
or a PC on the DH+ network to a MicroLogix controller on the
DH-485 network. This method uses an SLC 5/04 processor bridge
connection.
IMPORTANT
All devices should be set to the same maximum node
address.