Introduction to Explicit Messaging

Overview

The BMENOC0301/11 Ethernet communications module supports through the and protocols:

EtherNet/IP: Use the DATA_EXCH function block in application logic to create an EtherNet/IP explicit message.
Modbus TCP: Use the DATA_EXCH function block or WRITE_VAR and READ_VAR function blocks in application logic to create a Modbus TCP explicit message.

NOTE: A single Control Expert application can contain more than 16 explicit messaging blocks, but only 16 explicit messaging blocks can be active at the same time.

This chapter describes how to configure both EtherNet/IP and Modbus TCP explicit messages through these mechanisms:

DATA_EXCH function block (in application logic)
Control Expert graphical interface

explicit messaging

TCP/IP-based messaging for Modbus TCP and EtherNet/IP. It is used for point-to-point, client/server messages that include both data, typically unscheduled information between a client and a server, and routing information. In EtherNet/IP, explicit messaging is considered class 3 type messaging, and can be connection-based or connectionless.

EtherNet/IP™

A network communication protocol for industrial automation applications that combines the standard internet transmission protocols of TCP/IP and UDP with the application layer common industrial protocol (CIP) to support both high speed data exchange and industrial control. EtherNet/IP employs electronic data sheets (EDS) to classify each network device and its functionality.