Rockwell Automation Publication 1766-UM001O-EN-P - September 2021 65
Chapter 4 Communication Connections
Connect to a RS-485
Network
The network diagrams on the next pages provide examples of how to connect
MicroLogix 1400 controllers to the RS-485 network.
You can connect a MicroLogix 1400 controller to your RS-485 network directly
without using an external optical isolator, such as Advanced Interface
Converter (AIC+), catalog number 1761-NET-AIC, as shown in the illustrations
below, because Channel 0 is isolated within the controller.
MicroLogix 1400 controllers support various protocols on the RS-485 network,
including DH-485, DF1 Half-Duplex Master/Slave, Modbus RTU Master/Slave,
ASCII and DNP3 slave protocols. In this section, DH-485 protocol is used as an
example. Any physical connection should be the same as other protocols.
DH-485 Configuration Parameters
When MicroLogix communications are configured for DH-485, the following
parameters can be changed:
See Software Considerations
on page 181 for tips on setting the parameters
listed in Table 9.
Use a 1763-NC01 Series A or later (8-pin mini-DIN to 6-pin RS-485 connector) cable or
equivalent to connect a MicroLogix 1400 controller to a RS-485 network.
Table 9 - DH-485 Configuration Parameters
Parameter Options
Baud Rate 9600, 19.2 Kbps
Node Address 1...31 decimal
Token Hold Factor 1...4
A
TERM
B
COM
SHLD
CHS GND
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