The PC invasion

A new report offers further evidence that the future of industrial control may yet belong to the PC. We look at how it might all happen

The European PC-based control systems market will be worth $129million by 2004, following significant up-take by end user industries. This conclusion is drawn in a new report from Marketline International called PC-based Industrial Control Systems. The report incorporates a survey of over 500 industry executives in some of the largest automation end users in Europe and reveals that automotive, food and beverage industries hold the best potential for PC-based control and that end user opinion on the prospects for the technology is highly fragmented even within similar industrial sectors.

SPECIFIC BENEFITS

According to MarketLine, PC-based systems offer specific benefits to the automotive industry, and a number of high profile manufacturers have already adopted the technology. The food and beverage industry includes many enterprises which currently have little or no automation, but see investment in such technology as a way of boosting productivity, performance and profitability. PC-based control is what many have been waiting for.

This is not to say that PC systems don’t have their disadvantages. Brian Mayne of IMO Precision Controls Says: `The snag – and it is a very big snag with major down time implications – is that conventional PCs with screens, hard disks and keyboards, tend not to withstand the vibration heat, dust and mayhem of tough industrial environments as well as PLCs. Even with office based PCs, some 80% of all maintenance call outs are down to mechanical or electrical problems rather than electronic failures.’

OUT OF ACTION

Tim Clarke at Armagard agrees, `PCs draw air through their fans and distribute it across the electronics inside. Exposure to dust, vapours, fluids, oil, grease extremes of temperature and electrical magnetic disturbance can put the PC out of action very quickly. Rough handling, tampering and theft are also serious hazards. Dust includes general dust, carbon, paper, sugar, tobacco, tea, paint, rock and many others.’

Although they agree on the problems of using PCs in an industrial environment IMO and Armagard have different approaches to solving the problem.

Armagard constructs special enclosures to protect the PC from the rigours of the environment, they providing various models for the severity of the environment.

IMO has a software solution which runs on a Intel-based industrial PC platform and which transforms the processing power of the PC into a fully functional PLC. SoftPLC takes over the running of the PC: it needs no hard disk, screen, keyboard or proprietary operating system making it (IMO says) as reliable as any of the best PLCs.

SYSTEM INTEGRITY

But can the software and operating system stability be relied upon? how often does your PC crash? Ron Higginson of Moore Products says that even systems with robust crash proof operating systems that run the control software as one task and Windows NT as another need rebooting when Win NT crashes.

Higginson’s solution is to put the PC inside the robust, real-time controller environment keeping the benefits and controlling the weaknesses. You keep the PC’s strong points. MMI, data archiving user friendly configuration tools and lose the instability because it is monitored via a watchdog and restarted fully automatically or at least without interrupting control tasks.

It is different from a PLC, a DCS and a PC running SCADA in that the cost of the PC reduces to that of a few chips on a card when it is an embedded device within another machine, and the real time controller provides elegant PLC style sequencing functions and powerful DCS style continuous control, and the MMI function is handled through an embedded PC.

MarketLine consultant Martin Atherton says, `There is little doubt that the future of industrial control lies in the hands of the PC, but the current market situation is extremely complex. Many end users are not yet convinced that PC-based control can, or ever will, offer them the same functionality and reliability currently provided by proprietary solutions. In the long run, it will be the end-users who decide, but their task is not made any easier by the myriad of solutions, opinions and debates surrounding the issue.