For quite a while now there’s been a choice between compliance with the old Machine Safety Directive and the new one. Now that choice is almost at an end it’s time to embrace the benefits of these updated regulations, says Paul Considine of Wieland Electric
Whenever new regulations are imposed on us many people tend to focus on the perceived negatives, rather than ‘accentuating the positive’. During the transition phase between old and new Machine Safety Directives this was an option, but from the beginning of next year there is no choice.
In fact, many machine operators and manufacturers have chosen to comply with the latest legislation before the deadline. And experience shows that the benefits far outweigh the downsides. So, moving forward, the important thing is to ensure those potential benefits are turned into real benefits.
The primary benefit is the improved safety that compliance with the new(ish) standards EN ISO 13849-1 or EN (IEC) 62061 brings, compared to the old EN 954-1. This is because EN 954-1 is too simple to handle the programmable electronics that are used in modern safety systems, so it has effectively been superseded by technology. Consequently, the new regulations are addressing what has become standard practice in many applications.
A further benefit of EN ISO 13849-1 is it facilitates the wider use of programmable safety relays – at a time when the cost of such relays has come down considerably. There has also been a move towards greater modularity, exploiting the functionality of these newer processing technologies – which adds cost savings.
As a general rule of thumb, a system using three to four stand-alone safety relays can be replaced by a programmable system for about the same cost. With more extensive systems the savings will be even greater – and, as noted above, all such systems offer a number of benefits.
In taking advantage of these technologies, machine owners and operators are able to reduce overheads and achieve a fast return on investment.
Flexible logic
A benefit of programmable safety relays is they can be tested in the software before any installation work begins, using a flexible logic editor to make it quick and simple to spot potential problems and eliminate them at the design stage. As a result, much less time is spent in onsite testing, reconfiguration and re-testing, compared with dealing with stand-alone relays. In our experience, when equipped with these tools, electrical engineers are more inclined to try out different solutions to arrive at the best solution, because they can save the original settings and quickly restore the system if something doesn’t work.
Installation times are also reduced because while stand-alone relays require feedback loops and interconnecting terminals, programmable safety relays are wired back to a central I/O point. There are also fewer sub-systems overall, keeping the whole system simpler and less likely to develop faults.
Time-savings can also be achieved for commissioning because any errors are highlighted in the software. And if someone decides to make adjustments during this process and they don’t work, the original settings can be quickly restored through the software.
The software also incorporates a full reporting structure linked to the technical file, so that all information is recorded without manual intervention and reports can be generated very quickly. Feedback from users indicates this ease of reporting has helped them to understand their maintenance patterns in greater depth and utilise their resources more effectively as a result.
The time-saving benefits during design, installation and commissioning are of benefit to all parties, and the machine owner can also enjoy ongoing benefits through the life of the machinery. For example, when a fault occurs in a traditional design it can take a considerable time to locate it. In fact, finding the fault often takes longer than the time to fix it! Furthermore, that time will often be consumed by specialist engineers at an hourly rate that reflects their skills.
A benefit of programmable systems is they offer the diagnostic capability to make fault-tracing much quicker. So significantly less time is consumed in rectifying faults, downtime is reduced and less money is spent on specialist skills. Often, once the fault has been identified it can be put right without any specialist input over and above that of in-house engineers.
Consequently, there are many reasons for being positive about advances in machine safety, and taking advantage of the benefits programmable safety relays offer. There is also sense in teaming up with a company to help you maximise those benefits.
