Approved safety PLC system to be demonstrated at Railtex 2013

22 March 2013

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Approved safety PLC system to be demonstrated at Railtex 2013At Railtex 2013, which takes place at London's Earls Court from 30 April to 2 May, Pilz will present an automated half barrier level crossing demonstrator in which the PSS 4000-R Safety PLC system handles the control and signalling. In addition, the company will present a seminar on the use of industrial safety PLCs for a modern, future-oriented railway infrastructure. Pilz staff from the UK and other countries will be available during the exhibition to talk about the benefits of PLC technology for the rail sector, as the PSS 4000-R has already been used successfully for numerous rail industry applications.

Previously safety systems in the railway sector have largely used proprietary, specialist technology - much of it based around relay logic; however, this has often involved a lot of work for a one-off approval, particularly with regard to rail safety standards.

Components in the PSS 4000-R system (PLC header modules and I/O modules) already have the approvals necessary for railway applications, which minimises the time and effort needed for verification and validation work. Thanks to its scalability, the PSS 4000-R system can be used for SIL 2, SIL 3 and SIL 4 applications.

Various applications can be implemented using the PSS 4000-R:

  • Control functions on rolling stock, such as track laying machinery and traction units to SIL 2/SIL 3
  • Control functions/monitoring functions in signalling, such as signal monitoring on level crossings, control and safety technology, and signal box connection to SIL 2/SIL 3/SIL 4

The PSS 4000-R system is characterised by a particularly robust design and it meets the increased requirements from the railway sector. Additional benefits include intuitive programming with standardised EN/IEC 61131-3 editors and Ethernet-based communications.

Thales Germany has been using the PSS 4000-R. Mr Norbert Howe, the company's Director of Solutions for the German Business Area, Transportation Systems, states: "Pilz offers us standardised technology for developing signalling products. Pilz supports us to evolve our relay-based rail signalling products using state-of-the-art components which meet the highest environmental requirements with regards to temperature, EMC and mechanical load. Pilz can provide standard-compliant solutions through to SIL4-capable control systems in accordance with CENELEC 5012x."

Benefits of the PSS 4000-R for the rail sector can be summarised as:

  • A commercial off-the-shelf (COTS) control system from the automation world, expanded to meet the special requirements of the railway sector - suitable for use in the track area and on rolling stock.
  • Special modules with railway approval (CENELEC, TUV) to the standards: EN 50121-3, EN 50121-3-2, EN 50121-4, EN 50155, EN 50126, EN 50128 and EN 50129.
  • Scalable for safety functions in accordance with SIL 2, SIL 3 and SIL 4.
  • Less work involved for approval, reduced acceptance procedure thanks to the approved system.
  • High level of independence and transferability due to standardised programming in accordance with EN/IEC 61131-3. Furthermore, the Block Editor in the software can be used to create customised blocks that can be encapsulated/protected and reused at any time. Areas of responsibility and authority can therefore be defined and applications expertise protected.
  • Subsequent modifications: With the PSS 4000 it is possible to adapt the architecture retrospectively - thanks to modularisation, reusability of identical components and flexible customisation of hardware and software. Existing projects can therefore be expanded or enhanced at a later date.
  • Like other common PLC control systems, the PSS 4000-R operates with a 24V power supply. However, an input module for a 60V switching level is available specifically for use in the railway sector.
  • Ethernet-based communication: The control systems are networked using the Ethernet-based safety protocol SafetyNETp, so long distances of several kilometres can easily be bridged. The control system in the railway station/signal box can therefore communicate safely with the control system on the level crossing, for example. The system also supports other standardised Industrial Ethernet protocols.

David Collier of Pilz (UK) will be speaking in a seminar on Thursday 2 May at 12:30 on the subject of Industrial safety PLCs for a modern, future-oriented railway infrastructure.

For more information about the PSS 4000-R Safety PLC system or other safety products for applications in the rail industry, email , telephone +44 (0)1536 460766 or go to and enter Webcode 8485.

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