Is this the shape of thing to come in instrumentation and control? Robert Harrison, professor of automation systems at world-renowned Warwick Manufacturing Group (WMG), is working on what he describes as a 'lego' concept of flexible, modular, reconfigurable automation – systems that enable production lines to be quickly reconfigured, including from a control perspective, to suit changing requirements. Production lines and their controls are first modelled, using virtual engineering systems to establish requirements for additional sensors, tooling, etc, and new control code then generated from the revised process design.
"You will see a 3D visualisation of the production line equipment driven from the same control logic as drives the real system," explains Harrison. That will enable engineering teams of the future both to validate the system's control behaviour and to evaluate the line's ergonomics, along with machine interactions and any associated diagnostic requirements. "In fact, we can also use the virtual model to train operators on the new line, using the same operator interfaces as they will later use."
Sounds fanciful? Perhaps, but WMG is working right now with some major automotive, pharmaceutical and food industry partners on just such an approach to rapid production line redesign – including of automation and control systems. "In terms of control, we have a library of function blocks for PLCs and controllers. So by importing the existing network configuration into a database, we can capture its full functionality. Then we can do the mapping between the physical system and the simulation," says Harrison.
As for a little detail, he explains that machine automation is achieved using a flexible and modular architecture, involving independent PLCs and/or embedded controllers at each work centre. Control areas are then linked on an Ethernet network, using ProfiNet or Ethernet IP. And, with modularity right down to the function blocks, the result is highly distributed and very flexible automation.
Harrison is unequivocal. "In the virtual world, you have a lot of freedom to modify controls. You can also validate proposed processes without the cost or risk of physical models." The bottom line: system engineers get to a redesigned production line that is robust and validated, faster than is otherwise possible – meaning they can confidently adapt existing lines in realistic timeframes, and so boost plants' competitiveness.
Additionally, with work currently being undertaken by WMG on 'cyber physical' systems, if errors do occur – during installation or commissioning, for example – they can be automatically reported to maintenance, who will be offered data on fault location, history, appropriate skill sets, etc. Similarly, engineers will be able to harness 'augmented reality' to overlay relevant I/O visualisations and the like on PLC cabinets, to reveal problem connections, fault types, etc.
But WMG is far from alone in developing tools to improve the flexibility of equipment and the automation systems that govern its behaviour. Erstwhile SCADA (supervisory control and data acquisition) system developer Wonderware – initially bought by Invensys and subsequently Schneider Electric – has long since reinvented itself as a plant control systems development and visualisation software specialist.
Systems architect Paul Alcock recalls that the company climbed to stardom on the back of its InTouch software, aimed at system integrators wanting to configure PC-based HMIs (human-machine interface) for PLC or telemetry systems. Now, however, while retaining that role, it is also about enabling engineers to create much larger, software object-based distributed and redundant monitoring and control systems via the firm's System Platform environment, now at version 2014 R2.
Much grander in scope and more sophisticated in functionality, it includes advanced features such as 'situation awareness'. "Rather than all information always being provided on screen graphics, situation awareness reveals only key information that's relevant at the time," explains Alcock. "That makes operators' lives easier. They can identify faults and other issues – such as plants moving out of normal operating conditions – faster." In fact, System Platform behaviour is based on best practice screen designs for advanced alarm management, in line with EEMUA 191 (Engineering Equipment and Materials Users' Association), picking up colour codes and displaying accordingly.
However, there's much more to it. System Platform also enables advanced facilities such as auto-assigning I/O to control architectures involving pretty much any mix of controllers. That means it goes way beyond the mere logical representation of physical plant to what Alcock describes as an "operational intelligence system" that interfaces well with plant MESs (manufacturing execution systems), whatever their make-up. And that's not just for the initial set-up and commissioning. "You can maintain your original control system but extend it [in run time] by implementing a layer above, which can readily respond to plant changes, such as introducing wireless tags," explains Alcock.
It's a similar picture of rapid advancement right across the world of monitoring and control. Siemens' central technology officer Alan Norbury harks back to a time, not that long ago, when PLC manufacturers first adopted digital fieldbus technology (in place of hard-wired I/O connections) – in its case Profibus, based on the RS485 real-time multi-drop standard. A revolution in itself, it was soon to be superseded by another, with an initially shocking move to Ethernet.
Why the early misgivings? Because vanilla Ethernet, with CSMA/CD (carrier sense multiple access with collision detection, long since obsolete) did not support deterministic communications (guaranteed response in a defined timeframe – essential for automation). However, industry pressed for developments and the ensuing technology jump was to deterministic Ethernet, mostly in the form of Ethernet IP and ProfiNet. The benefits: lower cost commodity communications equipment; commonality of networks and skill sets; and easy links into business systems, where required, via Internet Explorer, etc. And users automatically get safe remote access for diagnostics and the like, since Ethernet ports go hand in glove with web server functionality.
On top of that, the ProfiEnergy option, for example, enables (typically) automotive plants not only to assess energy consumption when they are not manufacturing cars, but also to power down equipment during breaks to save energy. Other Ethernet-based machine communications options also include wireless access. On the one hand, that enables intelligent connection to remote devices (such as sensors and transmitters, but also remote controllers), where the cost of wiring would be prohibitive – for example on large process plants. But on the other, it also potentially facilitates some degree of agile manufacturing, by enabling easy additions/changes to factory automation systems.
Sounds good? Yes. However, as Norbury says, among the resulting challenges for today's systems engineers is how to migrate from older control and communications technologies to new, particularly given that some machines and plant may be 20 or 30 years old. It can be done, he insists, but the 'art' is in doing so while minimising downtime.
Is it worth the effort? That depends on several factors. Could being able to remotely access machine information, for diagnostics purposes, save money and/or improve production metrics, also reducing downtime and scrap? Might there be value in passing data to business systems to establish machine KPIs (key performance indicators) in near real time, as an indicator of potential problems and/or a basis for guiding CI (continuous improvement)?
As Mike Loughran, Rockwell Automation's business leader for architecture and software, puts it: "Customers might want to see something as simple as when their products will be despatched if they place an order tomorrow. If you're relying on older system technology, you're going to struggle to deliver that. But, by adopting Ethernet, you can do it in a secure and structured manner, leveraging standard technologies. And you can make the information available on mobile devices, too." ¦
