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Industrial communication

Modicon M221, M241 and M251 industrial Ethernet

Industrial Ethernet is the term used to designate industrial communication protocols using standard Ethernet physical layers such as:

> EtherNet/IP.
> Modbus TCP.
> TCP and UDP.

On an Industrial Ethernet network, it is possible to connect :
> Industrial products (industrial communication protocols) such as controllers, variable speed drives, robots, etc.
> Products using proprietary TCP / UDP based protocols.
In addition, it is possible to simultaneously use different Industrial Ethernet protocols on the same network.

Industrial Ethernet

EtherNet / IP protocol

EtherNet / IP is an industrial communications protocol based on the Common Industrial Protocol (CIP), owned and operated by ODVA, an independent international standards organization (www.odva.org).
EtherNet / IP results from the implementation of the CIP protocol over standard Ethernet.
EtherNet / IP operates on the same equipment and infrastructure as Modbus TCP, and both protocols can be enabled simultaneously and at any time on the network.
EtherNet / IP is a robust protocol that allows the use of advanced equipment such as cameras, robots, …

Advanced services and high performance

EtherNet / IP is object oriented. In each EtherNet / IP device, data is classified into objects and each device can be associated with several types of objects depending on the use for which it is intended. The integration of equipment is made easier thanks to predefined and standard objects.
The EtherNet / IP protocol uses an Originator / Target architecture for data exchange.

Modbus TCP protocol

Modbus has been the industry communication standard in place since 1979.
Modbus was combined with Ethernet during the Internet revolution to form Modbus TCP, a completely open Ethernet protocol.

Modbus TCP, simple and open
The Modbus application layer is simple and universally familiar with its 9 million installed connections.
> Thousands of manufacturers have already implemented this protocol. Many have already developed a Modbus TCP connection, and many products are currently available.
> The simplicity of Modbus TCP allows any fieldbus device such as an I / O module to communicate over Ethernet without the need for a powerful microprocessor or large internal memory capacity.

Modbus TCP, a standard

> The application protocol is identical on Modbus serial link and Modbus TCP; messages can be routed from one network to another without protocol conversion.
> Since Modbus operates on the upper TCP / IP layer, users benefit from IP routing devices that allow devices anywhere in the world to communicate without worrying about the distances between them.
Modbus and Modbus TCP are recognized as a field bus by the international standard IEC / EN 61158. They also comply with the “Chinese national standard” managed by ITEI.
The Modbus TCP protocol uses a client / server architecture for data exchange.

Modicon M221, M241 and M251 logic controllers

The Ethernet communication ports on board Modicon M221, M241 or M251 logic controllers and on the Modicon TM4ES4 communication module allow perfect integration of machines into factory network architectures.
Modicon M221, M241 and M251 controllers can be easily integrated into architectures such as:
> Machine to equipment (variable speed drives, remote input / output modules, dialogue terminals) with the input / output scanning function (I / OScanner).
> Machine to machine with NGVL function.
> Machine to supervision with Modbus Client / Server and EtherNet / IP adapter function.

Ethernet also brings transparency in the factory, in particular allowing from any point of the network and in a secure way thanks to the firewall functions:
> To program, monitor a controller or download an application.
> Access the parameters of equipment, variable speed drives for example.

A simple internet browser allows access to the machines at any time and regardless of their location, using a tablet or smartphone, for example, thanks to the web servers embedded in the Modicon M241 and M251 controllers.
Security can be enhanced by the use of VPN modems.

(1) SoMachine configuration software:

  • FDR: “Fast Device Replacement”,
  • DTM: “Device Type Manager”,
  • TVDA: Architectures tested, validated and documented.

(2) Integration as generic equipment.

Web servers

Pre-configured web server
From a simple internet browser available on PC, smartphone or tablet, this server allows the following “ready-to-use” functions:


> Without any prior programming:

  • Viewing the status of inputs / outputs.
  • Diagnosis of the controller, its extension and communication modules.
  • Diagnosis of communication ports.
  • Diagnosis of the I / O Scanner function.
  • Maintenance and configuration functions (EtherNet / IP, firewall, etc.).

> After configuration:

  • Visualization of data values.
  • Visualization of the evolution of these data over time (oscilloscope function).

Visu web server
The SoMachine programming software allows you to create custom pages for viewing and monitoring equipment. These pages are also accessible on any mobile device such as tablet, smartphone regardless of the operating system (iOS, Android, Windows).

Web server

Description of Ethernet services

Network Global Variable List (NGVL)
The NGVL protocol allows a controller to make data available to other controllers over an Ethernet local area network (LAN) or to subscribe to data published by other controllers that support the NGVL protocol thus allowing, for example , synchronization between control platforms.

Input / output scanning (Industrial Ethernet Manager)

The Industrial Ethernet Manager service is used to manage the exchange of remote I / O status on the Ethernet network, after a simple configuration and without the need for specific programming.
The I / O scanning is performed transparently using read / write requests according to the Modbus TCP or EtherNet / IP protocol, we then speak of Scanner Manager on Modbus TCP or Scanner Manager on EtherNet / IP .

Modbus TCP slave

This function is used to create a specific input / output table in the controller, accessible by the Modbus TCP protocol and accessible by a controller having the Modbus TCP I / O Scanner function.

Fast Device Replacement (FDR)

This service uses standard address management technologies (BOOTP, DHCP) and the TFTP (Trivial File Transfer Protocol) file management service to facilitate maintenance of Ethernet products.
The FDR service makes it possible to replace a product with a new one by carrying out its detection, its reconfiguration and its automatic restart by the system.

Accessing files by FTP (File Transfer Protocol)

This service allows access to controller files from, for example, a computer (FTP client) and to exchange files such as application program, data, etc.
This service is accessible even if the controller does not have an application program in memory.
Dynamic Host Configuration Protocol (DHCP)
This protocol is used to automatically assign an address to a controller (DHCP / BOOTP client). This address can be :
> Fixed and determined either in the SoMachine software or included in a post configuration file.
> Assigned by a controller having the DHCP server or BOOTP server function (such as the TM251MESE logic controller).

SNMP (Simple Network Management Protocol)

The SNMP protocol makes it possible from a network manager station to monitor and control the components of the Ethernet architecture and thus provide a rapid diagnosis in the event of a problem.
The SNMP protocol allows access to configuration and management objects that are contained in the “MIB” (Management Information Base) of the products.
Modicon M241 and M251 controllers support the “MIB 2 Standard” SNMP network management interface. A first level of network management is accessible via this interface; it allows the manager to identify the products making up the architecture and to retrieve general information on the configuration and operation of Ethernet Modbus TCP interfaces.

IP address filter (White listing)
IP addresses, authorized to access the controller can be loaded into the controller from either an SD card or an FTP client.

Locking of communication protocols

The SoMachine, NetManage (1), SNMP communication protocols as well as the Modbus, WEB and FTP servers can be individually locked in the SoMachine software.

EtherNet/IP target
This function is used to create a specific input / output table in the controller, accessible by the EtherNet / IP protocol and accessible by a controller having the Ethernet / IP originator function. EtherNet / IP target has the same role for EtherNet / IP as a Modbus TCP slave.

EtherNet/IP originator
The controllers having this function are at the origin of the exchanges with the equipment having the Ethernet / IP target function. EtherNet / IP originator has the same role for EtherNet / IP as a Modbus TCP master.

(1) The NetManage function automatically detects the controllers present on the network. It also offers the possibility of simply connecting to any controller present on the network in order to physically identify it by a visual or audible message and to modify the settings or manage the resident application.

Scanning of inputs outputs

Transparent ready class and functions

Transparent ready class and functions

Network characteristics of the Modicon M251 controller

Network characteristics of the Modicon M251 controller

Ethernet ports of logic controllers and Ethernet switch module

M221 logic controllers

(1) On TM221ME controllers…. : RJ 45 type connector for Ethernet network, with LED display of exchange speed and activity.
(2) On TM221CE … controllers: RJ 45 type connector for Ethernet network, with LED display of exchange speed and activity.

M241 logic controllers
(3) On TM241CE … controllers: RJ 45 type connector for Ethernet network, with LED display of exchange speed and activity.

M251 logic controllers

(4) On TM251MESE and TM251MESC controllers: 2 connectors connected by an internal RJ 45 switch for “Machine or Factory” Ethernet network, with LED display of exchange speed and activity.
(5) On TM251MESE controller: RJ 45 type connector for “field bus” Ethernet network with LED display of exchange speed and activity. This port can be used with the Industrial Ethernet Manager function.

TM4ES4 Ethernet switch communication module

(6) 4 RJ 45 connectors for Ethernet network with LED display of exchange speed and activity.

TM4ES4 Ethernet switch communication module

Industrial Ethernet Architecture

(1) Straight copper cords.
(2) Ethernet copper cable 2 shielded twisted pairs.
(3) ConneXium switches, unmanaged.

(1) Wireless Ethernet access.
Note: the ports of the M251 controllers and of the TM4ES4 communication module cannot be used for redundant architectures.

Industrial Ethernet Architecture

Industrial Ethernet or EtherNet / IP network architecture for Modicon M258 logic controllers, Modicon LMC058 and Modicon LMC078 motion controllers

(1) Straight copper cords.
(2) Crossed cords.
(3) Optimized twisted pair switch or twisted pair switches, unmanaged.
(3a) Twisted Pair Switches or Twisted Pair and Fiber Optic Switches.

Industrial Ethernet or EtherNet / IP network architecture for Modicon M258 logic controllers, Modicon LMC058 and Modicon LMC078 motion controllers

Transparent ready class and functions

Transparent ready class and functions

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