Introducing the Local Slave

Original instructions

About Local Slaves

The BMENOC0321 Ethernet communications module scans network modules on behalf of the M580 CPU.

However, you can enable the communications module as an (or ). When the local slave functionality is enabled, network scanners can access the M580 CPU data that is mapped to local slave assembly objects in the CPU program.

NOTE: The BMENOC0321 module continues to function as a scanner when it is enabled as an EtherNet/IP adapter.

The module supports up to 12 instances of local slaves (Local Slave 1 ... Local Slave 12). Each enabled local slave instance supports these connections:

one exclusive owner connection
one listen-only connection

Process Overview

These are the steps in the local slave configuration process:

Stage	Description
1	Enable and configure the BMENOC0321 module as a local slave.
2	Configure local slave instances in the scanner device. (Local slave instances correspond to each enabled local slave that is scanned.)
3	Specify the size of local slave input and output assemblies in the scanner device (originator). (Use sizes that match the input and output sizes of the enabled local slave.)

Implicit and Explicit Messaging

In its role as an EtherNet/IP , the BMENOC0321 module responds to these requests from network scanners:

implicit messages: Implicit messaging requests are sent from a network scanner device to the communications module. When the local slave functionality is enabled, network scanners can perform these tasks:
- Read messages from the communications module.
- Write messages to the communications module.
Implicit messaging is especially suited to the exchange of peer-to-peer data at a repetitive rate.
explicit messages: The communications module responds to explicit messaging requests that are directed to its CIP objects. When local slaves are enabled by the CPU, explicit messaging requests can access the communications module's CIP assembly instances. (This is a read-only function.)

Scanner Configuration

Configure the scanner:

Configuration	Description
Control Expert	If the scanner device that is used to communicate with the local slave can be configured using Control Expert, use the DTMs that correspond to the BMENOC0321 modules to add those modules to your configuration.
third-party scanner	Third-party EtherNet/IP scanners that access the local slave assembly instances through the BMENOC0321 module do so with respect to the assembly mapping table. That module is delivered with its corresponding EDS file. Third-party scanners can use the contents of the EDS file to map inputs and outputs to the appropriate assembly instances of the BMENOC0321 module.

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.

The functionality offered by Schneider Electric EtherNet/IP communication modules that allows a scanner to take the role of an adapter. The local slave enables the module to publish data via implicit messaging connections. Local slave is typically used in peer-to-peer exchanges between PACs.

An adapter is the target of real-time I/O data connection requests from scanners. It cannot send or receive real-time I/O data unless it is configured to do so by a scanner, and it does not store or originate the data communications parameters necessary to establish the connection. An adapter accepts explicit message requests (connected and unconnected) from other devices.

UDP/IP-based class 1 connected messaging for EtherNet/IP. Implicit messaging maintains an open connection for the scheduled transfer of control data between a producer and consumer. Because an open connection is maintained, each message contains primarily data, without the overhead of object information, plus a connection identifier.

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.

(common industrial protocol) A comprehensive suite of messages and services for the collection of manufacturing automation applications (control, safety, synchronization, motion, configuration and information). CIP allows users to integrate these manufacturing applications with enterprise-level Ethernet networks and the internet. CIP is the core protocol of EtherNet/IP.

(electronic data sheet) EDS are simple text files that describe the configuration capabilities of a device. EDS files are generated and maintained by the manufacturer of the device.