Is Profisafe worth waiting for?

People say that all good things come to those who wait. But after waiting a long time, you start to wonder if the thing you are waiting for can really be that good after all. Profisafe, the fail-safe fieldbus protocol based on Profibus, was starting to look as if it might never take off, despite the early signs of success for its little sister, Asisafe, the fail-safe protocol based on AS-Interface. Someone, who will remain nameless but is recognisable by his look of relief, even went so far as to say that if no Profisafe products were launched at Hanover, then Profisafe would become a bit of an embarrassment.

And now, thanks to a handful of relatively low-key launches at Hanover, we are indeed starting to see real Profisafe-compatible products becoming available. This will be very comforting for those companies who have supported the development of the protocol and who have invested heavily in developing suitable processors.

The list of compatible products is certainly not yet what you would call extensive, but it is a start. And, hopefully, it will encourage more manufacturers to launch those products that we keep being told are 'on the drawing board'. Erwin Sick, Turck and Siemens are among those leading the way with IP67 remote I/O modules, controllers, light curtains and a laser area scanner. Later this year (or early next year) Siemens will have a new processor that will reduce the cost of implementing a Profisafe system, and there should also be a Profisafe version of the Sinumerik 840D CNC controller and a series of Profisafe motor starters. Bob Squirrel, chairman of Profibus UK, reckons that several other manufacturers also have products that are not far away from being launched.

Both Erwin Sick and Turck have opted to concentrate on IP67 remote I/O modules that can be used to link standard safety components to a Profisafe fieldbus. The logic is that this is the way robot cells and similar areas of automated plant are currently wired, so there is little point in offering users a full range of safety devices with an integral Profisafe interface. Besides, it is unlikely to be cost-effective to offer all of the safety products with all of the safety fieldbus interfaces as alternatives.

Even without these new products, Profisafe is certainly no longer just a pipedream; there are already operational Profisafe installations, though they currently only use standard I/O rather than Profisafe-compatible I/O. Furthermore, at least one automotive manufacturer is rumoured to be considering using Profisafe for a press line.

Nevertheless, it seems rather optimistic to hope that Profisafe's market penetration in the UK will result from customer demand in advance of product being available. Personally, I would rather buy a house than buy the foundations and a reassurance from the architect that the walls, roof, doors and windows will be designed at an unspecified future date!

As part of the education process, Profibus UK is organising a seminar on 18 July to explain how Profisafe addresses key functional safety issues, and how a Profisafe system can be implemented. The seminar will be led by Wolfgang Stripf, chairman of the Profisafe technical committee, and delegates will also benefit from hearing first-hand the HSE's perspective on fieldbus and functional safety - delivered by Simon Brown, who heads the control and instrumentation systems section of the HSE's technology division. If any reader would like to attend, contact the Profibus Group on 01489 589574 or e-mail uk@profibus.com.

It is hard to decide yet whether Profisafe has been worth waiting for. On paper at least, it certainly has its attractions, based as it is on Europe's leading industrial network (according to a new Frost & Sullivan report). In which case, it is still difficult to comprehend why manufacturers have been so slow to launch Profisafe products. But let's hope that the few will soon become the many.