Industrial Ethernet

Typical configuration example for redundant plant bus

The plant bus and the terminal bus for multi-user systems with client/server architecture are implemented with Industrial Ethernet, a powerful area and cell network for industrial applications in line with the international IEEE 802.3 standard (Ethernet). Bus structures with optical rings are particularly suitable for this because of their interference immunity and high availability.

In medium-sized and large plants with high requirements, SIMATIC PCS 7 relies on modern FastEthernet and Gigabit technology. This combines the high reliability of optical rings with the scalable performance of switching technology and high transmission rates of up to 10 Gbps.

Ethernet is now the number 1 network technology in the global LAN environment. Ethernet offers important characteristics that can give you significant advantages for your application:

• Fast commissioning through simple connections
• High flexibility since existing networks can be extended without any adverse effects
• High availability thanks to redundant network topologies
• Almost unlimited communications performance because scalable performance is available through switching technology if required
• Networking of different application areas (e.g. office and production)
• Investment security through continuous compatible further development
• Plant-wide clock system permits exact assignment of events within the entire system

Ethernet technology for industrial environments

With Industrial Ethernet, SIMATIC NET expands Ethernet technology with future-proof network components with special features and capabilities for use in industrial environments, for example:

• Rugged design, suitable for harsh industrial environments
• Fast local assembly using the FastConnect cabling system
• High fault tolerance due to redundancy and fast redundancy switchover, from bumpless redundancy through PRP and HSR to ring redundancy with MRP
• Continuous and central monitoring of network components with a simple yet effective signaling concept, and network management software

The following Ethernet communications interfaces are used in the various SIMATIC PCS 7 subsystems (ES, OS, AS etc.):

• Interface modules integrated onboard
• Simple network adapters
• Special communications modules, e.g. CP 1623 and CP 1628

They are defined when selecting the respective system components, depending on the requirements. You can find more information in the section "System connection of PCS 7 systems".

The communication stations can be integrated in the terminal bus and the plant bus using Industrial Ethernet switches of the SCALANCE X product family. These switches offer scalable performance at an attractive price and support a wide variety of configuration options.

Configuration example for plant and terminal bus

Terminal bus

Client-server and server-server communication is carried out on a dedicated Ethernet LAN. The communication network identified as a terminal bus can be implemented with standard SIMATIC NET components such as Industrial Ethernet switches, onboard interface modules, network adapters, communications processors (CP), cabling, etc.

A ring design avoids communication failures should the line become damaged or disconnected at a particular point. To further increase availability, it is also possible to distribute terminal bus communication over two redundant rings. Each PCS 7 station is connected to one of two Industrial Ethernet ports on each of the two separate rings. The SIMATIC NET SOFTNET‑IE RNA communication software on the PCS 7 stations organizes communication processes based on the PRP. Non-PRP-enabled terminal devices that have only one Industrial Ethernet port can be integrated in the redundant terminal bus via SCALANCE X204RNA.

According to IEC 62439-3, the Parallel Redundancy Protocol (PRP) is based on double transmission of message frames over two separate networks (Ring 1, Ring 2). On the sender side, the SOFTNET-IE RNA software or SCALANCE X-200RNA network access point duplicates the message frame arriving from the sender and feeds one message frame to Ring 1 and the other to Ring 2. On the receiver side, the software or network access point forwards the first incoming message frame to the recipient. The second message frame from the second LAN is discarded. Transmission of the message frame is thus always ensured without delay if an error occurs.

Industrial Ethernet plant bus

The automation systems (AS) communicate with one another and with the engineering system and Operator Systems (Servers/Single Stations) over the Industrial Ethernet plant bus. This can be configured in a similar way to the terminal bus, using SIMATIC NET standard components such as Industrial Ethernet switches, network adapters, communications modules (CP), cabling, etc. For small plants with up to 8 standard automation systems per Operator System, Single Stations and servers can be efficiently operated on the plant bus using "Basic Communication Ethernet" (BCE) and a FastEthernet network adapter. The CP 1623/CP 1628 communications module is always required if more than 8 automation systems or redundant 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 requirements, 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 high-availability S7 connection (4‑way redundancy). One switch each takes over the function of the redundancy manager for each ring. The current switches of the SCALANCE X‑500, X‑400, X‑300 and X‑200 product lines can act as redundancy manager in a ring.

Note:

Detailed information on Industrial Ethernet and network components can be found in Catalog IK PI, in the Industry Mall, or in Catalog CA 01 under "Industrial Communication".