Siemens ST PCS 7 manual OS LAN terminal bus, Industrial Ethernet plant bus

© Siemens AG 2007

Communication

Industrial Ethernet

Introduction

■Design

In the various SIMATIC PCS 7 subsystems (ES, OS, AS etc.) on- board interface modules, simple network cards or special com- munications processors (e.g. CP 1613) are used as communica- tion interfaces. These are defined when selecting the respective system components depending on the requirements (for further information, refer to page 9/28).

The communication nodes are integrated into the bus with the aid of Industrial Ethernet switches. The modern Industrial Ether- net switches from the SCALANCE X range are to be recom- mended in particular. These offer scalable performance at an attractive price and support a wide variety of possible configu- rations. Further alternatives result by using the tried and tested ESM and OSM switches.

Client Client

OS-LAN (Ethernet), ring 1 OS-LAN (Ethernet), ring 2

9 Redundant servers

Redundant Industrial Ethernet plant bus (double ring)

AS 412H/

AS 414H/

AS 417H

Example configuration with plant bus and OS LAN with two redundant rings

OS LAN (terminal bus)

Client-server and server-server communication is carried out on a dedicated Ethernet LAN. The communication network identi- fied as OS LAN or terminal bus can be implemented with stan- dard SIMATIC NET components such as switches, onboard in- terfaces, network cards, communications processors (CP), cables etc.

A ring design avoids communication failures if e.g. the line is damaged or opened at a particular point. To increase the avail- ability even further, the OS LAN can also be distributed redun- dantly between two rings which are connected together by two pairs of switches (see example configuration). The switches from the SCALANCE X-400, X-300 and X-200 IRT ranges have the standby redundancy function required for this. Each of the redundant servers and clients can then be connected to both rings via two separate interface modules (redundant terminal bus adapter package). Communication is as standard on ring 1. Communication on ring 2 is only activated in the event of a fault on ring 1 which is relevant to the redundant switchover.

Industrial Ethernet plant bus

The automation systems (AS) communicate with one another and with the engineering system and operator systems (serv- ers/single stations) over the Industrial Ethernet plant bus. This can be designed analogous to the OS LAN with standard SIMATIC NET components such as switches, network cards, communications processors (CP), cables etc. In the case of small plants with up to 8 standard automation systems per oper- ator system, single stations and servers can be operated cost- effectively on the plant bus using "Basic Communication Ether- net" (BCE) and a FastEthernet network card. The CP 1613 com- munications processor is always required if more than 8 stan- dard automation systems or fault-tolerant automation systems are used.

As far as availability is concerned, ring topologies are always the first choice for the plant bus. With particularly high availability re- quirements, the plant bus can also be configured as a redundant double ring (two CPs per AS CPU and OS server). Double faults such as a switch failure on ring 1 with a simultaneous interruption in the bus cable on ring 2 can then be tolerated. The two rings in such a configuration are physically separated. The coupling partners are linked together logically when configuring with NetPro over a fault-tolerant S7 connection (4-way redundancy). One switch each takes over the function of the redundancy man- ager for each ring. The current switches of the SCALANCE X-400, X-300, X-200 IRT and X-200 ranges can be used as the redundancy manager in a ring.

Note:

Detailed information on Industrial Ethernet and on the network compo- nents can be found in Catalog IK PI, in the A&D Mall, or in Catalog CA 01 under "Communication/Networks/SIMATIC NET communication sys- tems".

9/4

Siemens ST PCS 7 · November 2007