A-B 1769-L38ERMSK CompactLogix 5370 L3 Controllers

Modbus Support

To use Logix5000 controllers on Modbus, connect the controllers through the 

serial port and execute specific ladder logic routines. 

A sample controller project is available with RSLogix 5000 Enterprise programming software. 

Broadcast Messages over a Serial Port

You can broadcast messages over a serial port connection from a master controller 

to all of its slave controllers by using several communication protocols. 

Those protocols are the following:

• DF1 Master

• DF1 Radio Modem

• DF1 Slave

Broadcasting over a serial port is achieved using the ‘message’ tag. 

Because messages are sent to receiving controllers, only the ‘write’ type messages can be used for broadcasting. 

The broadcast feature can be set up by using ladder logic programming software or Structured Text programming software.

The broadcast feature can also be set by modifying the path value of a message tag in the tag editor.

For this example, Ladder Logic programming software will be used.

The EtherNet/IP communication modules:

• support messaging, produced/consumed tags, HMI, and distributed I/O.

• encapsulate messages within standard TCP/UDP/IP protocol.

• share a common application layer with ControlNet and DeviceNet.

• interface via RJ45, category 5, unshielded, twisted-pair cable.

• support half/full-duplex 10 Mbps or 100 Mbps operation.

• support standard switches.

• require no network scheduling.

• require no routing tables.

In this example:

• the controllers produce and consume tags amongst themselves.

• the controllers initiate MSG instructions that send and receive data or configure devices.

• the personal computer uploads or downloads projects to the controllers.

• the personal computer configures devices on an EtherNet/IP network.

EtherNet/IP Network Communication

The EtherNet/IP network offers a full suite of control, configuration and data 

collection services by layering the Common Industrial Protocol (CIP) over the 

standard Internet protocols, such as TCP/IP and UDP. This combination of 

well-accepted standards provides the capability required to both support 

information data exchange and control applications.

The EtherNet/IP network also uses commercial, off-the-shelf Ethernet 

components and physical media, providing you with a cost-effective plant-floor solution.

For EtherNet/IP communication, you can use these CompactLogix controllers with a built-in EtherNet/IP communication port:

• 1769-L32E CompactLogix controller

• 1769-L35E CompactLogix controller

1756-OB16IS module Rockwell ControlLogix 16 digital output

1756-OB32 module Rockwell ControlLogix 32 digital output

1756-OB8 module Rockwell ControlLogix 8 digital output

1756-OB8EI module Rockwell ControlLogix 8 digital output

1756-OB8I module Rockwell ControlLogix 8 digital output

1756-OC8 module Rockwell ControlLogix 8 digital output

1756-OF4 module Rockwell ControlLogix 4 analog

1756-OF6CI module Rockwell ControlLogix 6 analog

1756-OF6VI module Rockwell ControlLogix 6 analog

1756-OF8 module Rockwell ControlLogix 8 analog

1756-OF8H module Rockwell ControlLogix 8 analog

1756-OG16 module Rockwell ControlLogix 16 digital output

1756-OH8I module Rockwell ControlLogix 8 digital output

1756-ON8 module Rockwell ControlLogix 8 digital output

1756-OV16E module Rockwell ControlLogix 16 digital output

1756-OV32E module Rockwell ControlLogix 32 digital output

1756-OW16I module Rockwell ControlLogix 16 digital output

1756-OX8I module Rockwell ControlLogix 8 digital output

1756-PA72 Module Rockwell ControlLogix AC Power Supply

1756-PA75 Module Rockwell ControlLogix AC Power Supply

1756-PA75R Module Rockwell ControlLogix AC Power Supply

1756-PAR2 Module Rockwell ControlLogix AC Power Supply

1756-PAXT Module Rockwell ControlLogix XT Power Supply

1756-PB72 Module Rockwell ControlLogix DC Power Supply

1756-PB75 Module Rockwell ControlLogix DC Power Supply

1756-PB75R Module Rockwell ControlLogix DC Power Supply

1756-PBR2 Module Rockwell ControlLogix Power Supply