SIL 4 PLC interlocking reduces lifecycle costs



New PLC interlocking with COTS safety controllers offers SIL 4 safety and reduces lifecycle costs by 30%

Consulting and engineering firm Movares has implemented a PLC interlocking based on industrial COTS (commercial off-the-shelf) hardware from HIMA Paul Hildebrandt GmbH for ProRail, the state-owned Dutch railway infrastructure enterprise.

The Santpoort Noord railway station project is the world`s first PLC interlocking for main lines that satisfies the requirements of the highest safety level, SIL 4, in accordance with CENELEC. The PLC interlocking solution is based on a HIMax® controller system and satisfies ProRail requirements for safety, availability, openness and lower lifecycle costs.

“We project that lifecycle costs will be at least 30% less than with other electronic interlocking solutions,” said Jorn Pruntel, Department Manager, Rail Signaling Systems at ProRail. The savings will be achieved through lower initial project costs, significantly lower maintenance and repair costs, lower costs for training the development and maintenance teams, and through less-expensive COTS hardware.

PLC interlocking, based on open industry standards, also addressed ProRail’s desire for a vendor-independent solution. Previously, dependence on specific vendors for component purchase, engineering, maintenance and modification led to higher costs for ProRail. “The openness of the HIMax control system introduces the possibility of implementing any established protocol and external device throughout the project’s lifecycle,” says Frits Makkinga, Director Innovation Division Rail at Movares Nederland.

The first PLC interlocking is in operation at Santpoort Noord since July 2012. In December 2012, ProRail certified the PLC interlocking solution for the entire Dutch railway network. By the end of 2014 Movares will implement a second PLC interlocking with COTS components from HIMA for ProRail at the Beverwijk railway station. This interlocking is scheduled to begin operation in 2015.

In 2011, the HIMax safety system was the first controller for main lines to receive SIL 4 certification, in accordance with CENELEC. Scalable redundancy of the HIMax system contributes to its effectiveness for railway stations and traffic hubs. As a plug and play system with hot-swap functionality, the system also makes possible cost-effective replacement of components without interrupting operation. The SILworX® engineering tool enables user-friendly and intuitive programming of the controllers and includes function blocks that significantly simplify the test and validation process for future applications. 


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Source: Movares Nederland B.V. in Utrecht


Tel: +49 2636 809955


Endcustomer: ProRail
Application: PLC interlocking based on industrial COTS (commercial off-the-shelf)
Hardware: HIMax
Safety level: SIL 4 in accordance with CELENEC