Beckhoff’s control systems prove critical to smoke control in the London Underground.

As half a million Tube passengers travel through central London every day, the capital’s jam-packed train carriages are already at overcapacity. Transport for London (TfL)’s Crossrail project needed to ensure that all standards for smoke ventilation were met in tunnels and stations. To put the right smoke control system in place, Kernow Controls and Intecre turned to Beckhoff’s powerful simulation technology. With this, the proposed controls installation was signed-off first-time — a rarity in today’s strictly-regulated rail industry.

London’s Elizabeth line, which aims to serve 200 million people a year, includes ten newly built and 30 upgraded stations. These span more than 100 kilometres from Reading in Berkshire to Heathrow in the west. Kernow Controls, a buildings control specialist, was brought in to deliver the scheme design for the smoke control systems’ (SCS) automation solution at Whitechapel Station.

“A correctly-working SCS redirects hazardous smoke and fumes in the instance of a building fire,” said Drew Dorling, managing director of Kernow Controls. “The intent is to ensure a smoke free pathway for first responders, fire officials and members of the public.”

“There’s an added complexity here, as the SCSs need to be integrated with the Crossrail system-wide control centre for remote override and control. Responses to events must be co-ordinated on a system-wide level.”

Choosing automation

In the early stages of the design process, Kernow Controls selected Beckhoff Automation, the industrial automation provider, as its desired manufacturer for the Crossrail project. While the brief for the project was not specific to any product or manufacturer, it became apparent during the design development phase that the project’s demands would necessitate a robust system operation. This led the Kernow team to Beckhoff’s offering.

“Having worked with Beckhoff’s team before through Intecre Limited, we were already aware of the company’s extensive product range and its offering of supplementary software. More importantly, we knew that Beckhoff’s equipment offers flexible integration paths to third-party systems and field devices, as well as management-level equipment,” continued Dorling.

Before now, system simulation and virtual commissioning have been predominantly associated with the improvement and optimisation of systems belonging to the “smart factory”. Today, the full extent of the technology’s capabilities is being demonstrated beyond a manufacturing environment, as in this particular project.

Central platform

Building on Beckhoff’s core principle of building all automation functions into a central platform, TwinCAT incorporates a programmable logic controller (PLC), motion control, robotics, high-end measurement technology, the Internet of Things (IoT) and human machine interfaces (HMIs).

For the Elizabeth line, Beckhoff’s automation-level controllers have been integrated using industry standard protocols to the management-level HMI. At this level, intuitive touch screens provide real-time and historical data, status, alarms and graphical visualisation of the smoke control system.

Kernow Controls suggested to include automated test routines for all safety critical equipment. This was adopted by Crossrail’s Chief Engineering Group (CEG) after all initial tests were complete, and instructed across all the station’s SCSs. The enhancement was incorporated easily into the operational system software, via the use of Intecre’s modular software approach. This ensured a simpler implementation, with no rework to the core smoke control. Full regression tests of the core functionality were carried out in a simulation, and all new functionalities were tested in the same way. It was a powerful demonstration of the system’s robustness, maintainability and flexibility.

The end result provides London Underground (LU) with the opportunity to conduct regular system tests, activated manually or scheduled automatically, to ensure that all components within the system are health checked. Combined with the automated test results, this solution provides documented evidence for compliance, fault identification and reporting.

This data details compliance with relevant standards, and highlights any system faults and the health of the system in a format that doesn’t require the station manager to have specialist engineering knowledge.

Reduced costs

“By using Beckhoff’s cutting-edge technologies, with Kernow Controls’ domain expertise and Intecre’s modular software and modelling approach, we can identify issues within an environment with complex interfaces across many systems,” said Mark Lazarides, managing director of Intecre Limited. “The modelling and simulation of systems, and their physical responses, offers valuable insight before any change becomes costly.”

Intecre developed the TwinCAT software in line with Object Oriented Design (OOP) principles. While this offers many benefits for testing small units of the software, it also results in much less code being written, thereby improving the quality and maintainability.

Lazarides explained: “Crucially, we extended the concept of mocking-up test objects to build full simulations for each component that “touches the real world” — like differential pressure sensors, fans and more.

“By simulating each of these objects, we were able to quickly begin simulating whole stations with multiple controllers. We made sure that each simulation object had realistic timings and introduced a range of failure modes for each. Indeed, we needed to test failure modes to ensure the robustness of our solution.”

The Kernow Controls team was able to fully develop its SCADA systems against these simulations, and the resulting suite of software became an incredibly powerful tool. The software suite has ensured that every single alarm and feedback signal can be tested. The effects of that signal across the station systems can also be assessed, and the impact of late changes to alarm signals or equipment lists were also mitigated.

Overcoming complexity

Because the proposed system was so critical, Kernow Controls worked closely with Beckhoff throughout the design process and specification stages. By working with a specialist like Beckhoff, companies have additional support on-hand to help with any technical challenges that arise during the project.

Following the project’s success, a systems integrator for another Crossrail station subsequently procured the automation package from Kernow Controls. Intecre’s modular approach to the software has ensured a high degree of reuse of tried and tested software, which was adapted to the third-party system integrator’s requirements with consultation from Kernow Controls.

As the demand for increased rail capacity continues, complex projects like the Elizabeth line offer more than an alternative route for the half a million London commuters that rely on the Tube, every day. By choosing the right automation solutions provider, the journey to completion can be de-risked and delivered with higher quality, first time. With an optimised smoke control system in place, travellers also benefit from safer and well-ventilated train stations throughout their journey.

www.beckhoff.co.uk