The following table provides an overview of which components are required for a redundant OS single station or OS pair of servers depending on certain criteria:

Connection to plant bus

Components for connection of redundant OS single stations / OS servers on the plant bus

Redundant plant bus

The Operator Systems (single stations or servers) communicate with the automation systems via the Industrial Ethernet plant bus. The following special points must be observed for redundant configurations:

• BCE communication with the 10/100/1000 Mbps Ethernet card is generally sufficient even for redundant operator stations. This allows the connection of up to 8 automation systems per server pair (AS single stations only, not AS redundancy stations). The BCE license is included for the BCE versions of the SIMATIC PCS 7 Industrial Workstation. It is also valid for an additional desktop adapter network adapter.
• Industrial Ethernet communication via CP 1623 (pre-installed in the IE version of the SIMATIC PCS 7 Industrial Workstation) or CP 1628 (with extra security functions) is required in the following cases:
  • The number of automation systems per OS is larger than 8.
  • Redundant automation systems (AS redundancy stations) are used.
• The IE versions of the SIMATIC PCS 7 Industrial Workstation are equipped with a CP 1623 and SIMATIC NET HARDNET‑IE S7 communication software, licensed for up to four CP 1623/CP 1628 (4x license). If lower-level AS redundancy stations are to be connected, however, SIMATIC NET HARDNET‑IE S7‑REDCONNECT is required. The SIMATIC NET product HARDNET-IE S7REDCONNECT PowerPack (license for 4 units) can be used to upgrade features.
• If an operator station with BCE communication is to be upgraded for operation with AS redundancy stations, a CP 1623 or CP 1628 communication module is required in addition to the SIMATIC NET HARDNET‑IE S7‑REDCONNECT (4x license).
• If the plant bus is to be designed as a redundant dual ring, you require two interface modules (2 x Ethernet network adapters 10/100/1000 Mbps or 2 x CP 1623/CP 1628) per OS single station or OS server.

The communication software for CP 1623 or CP 1628 is always supplied with the SIMATIC PCS 7 software and installed in line with the operating system.

In order to activate this communication software, you may need additional licenses for the

• SIMATIC NET HARDNET‑IE S7,
• SIMATIC NET HARDNET‑IE S7‑REDCONNECT or
• SIMATIC NET HARDNET-IE S7 REDCONNECT PowerPack communication products.

Connection to terminal bus

Redundant terminal bus

You can connect clients and servers to the terminal bus using integrated Industrial Ethernet interfaces or a desktop network adapter card.

A configuration with two separate rings is recommended for the redundant, fault-tolerant terminal bus. Communication is performed in this case using the Parallel Redundancy Protocol (PRP) in accordance with IEC 62439‑3. Each PCS 7 station should be connected to one of two Industrial Ethernet interfaces on each of the two separate rings.

The SIMATIC NET SOFTNET‑IE RNA communication software on the redundantly connected PCS 7 stations organizes communication processes based on the PRP. Therefore, SIMATIC NET SOFTNET-IE RNA communication software is required on each of the redundantly connected PCS 7 stations.

Connecting non-PRP-enabled devices

Up to 2 non-PRP-enabled devices that have only one Industrial Ethernet port, such as SICLOCK TC 400, a WLAN access point or an infrastructure computer, such as DNS, WINS, DHCP or a file server, can be integrated into a redundant, fault-tolerant terminal bus with PRP via a SCALANCE X204RNA.

Product versions of the SCALANCE X204RNA:

• SCALANCE X204RNA
  Router in plastic housing with 4 electrical ports for connecting up to two non-PRP-enabled terminal devices to redundant networks
• SCALANCE X204RNA EEC
  Router in metal housing with two electric terminal device ports and two optical/electrical combo ports for network connection of up to two non-PRP-enabled terminal devices to redundant networks

SCALANCE X‑200RNA is typically installed with the stations to be connected in a control cabinet.

For information on configuration and accessories such as cable material, plug connectors and transceivers, see section Communication, Industrial Ethernet, System Connection PCS 7 Systems.

For more information and technical specifications for the two SCALANCE X204RNA product versions, see Catalog IK PI.

For details on redundant SIMATIC PCS 7 configurations, refer to the manual "Fault-tolerant Process Control Systems".

Subsequent conversions

It is common practice to retroactively change or expand a plant. The following SIMATIC PCS 7 OS Software ConversionPacks support both retrofitting of the redundancy functionality, as well as the conversion from redundant OS single stations to redundant OS servers:

• SIMATIC PCS 7 OS Software ConversionPack 2x Single Station to Single Station Redundancy
  for converting two OS Single Stations to OS Single Station Redundancy
• SIMATIC PCS 7 OS Software ConversionPack 2x Server to Server Redundancy for converting two OS Servers to OS Server Redundancy
• SIMATIC PCS 7 OS Software ConversionPack Single Station Redundancy to Server Redundancy for converting two redundant OS Single Stations from OS Single Station Redundancy to OS Server Redundancy