April 2021

Insight April 2021 www.pwemag.co.uk Plant & Works Engineering | 11 • managing passwords properly, or avoiding them by using RFID tags and alternatives. Standard practice The ISO standard 62443 (industrial communication networks, network and systems security) deals with IT security and automation. It currently offers the best guide for both operators and device manufacturers when it comes to implementing security efficiently. However, as Eve Edwards confirmed, standards are lagging badly in this area. As technology moves forward at pace, it takes a while for standards committees and their publications to catch up. Martin Kidman gave the example of sensing devices based on radar, even though radar is not actually mentioned in most of the standards. Standards are now being drawn up so that they are almost “technology-agnostic”. They are being written around the requirements that a device needs to meet, rather than the technology employed. The requirements are the same, even if the device is actually based on a different technology. Martin Kidman observed that, historically, there has always been a perception that safety has a negative impact on productivity – put simply, stopping movement creates downtime. “When I started out as a test engineer on the Low Voltage Directive back in my early 20s, safety was seen as a cut-off device,” he recalled. “So you had thermostats for temperature fuses and for current, and the focus was basically turning everything off. Sometimes in industry, there can be a similar mentality about safety. You often get an angry production manager storming down the aisle!” But he argues that if you can design properly, you can reduce the impact of safety and can even start to get marginal gains, which can aggregate into quite large gains. “As a typical example, if we look at a mechanical press, normally you’d have a safety light curtain across the front, and hopefully, if you put your hand through, it would stop the press,” he explained. “And then you’d have to press the reset button, and you’d often see a two-hand control in front of the press to start a press cycle. “You can also speed up the cycle times by applying different techniques – such as presence sensing device initiation (PSDI),” he continued. “This is where you add additional motion control sensors such as cams, proximity switches and encoders. And this then becomes part of the safety control system.” With a more dynamic approach to safety, designers can now create systems capable of allowing continuous working. Whereas safety used to be added at the end, designers are now considering functional safety from the beginning. “We work with lots of customers in industry before even a bolt has been screwed in,” Kidman reported. “We have many customers considering concepts from the beginning – like localisation, navigation, safe, dynamic field switching, safe position, safe speed, and even wireless safety, in some cases.” He recommends reaching out to experts “from the beginning of a project, rather than just sticking safety on at the end, because nine times out of ten, it’s much more costly to do that, and much more difficult to do.” Integrated systems In the final section of the Webinar, Eve Edwards led on integrated manufacturing systems and risk assessments. She began by referring to a sightly lesser-known standard called ISO 11161, that covers integrated manufacturing systems – and is currently being rewritten. With multiple machines, large lines integrate those machines with each other. There may be converters or robots in between. ISO 11161 attempts to cover the additional level of associated risk. Users need to consider which bits of an installation can be shut down safely on their own, and which bits you can turn off while others keep running. How do they interact with each other? In most ISO standards, this is not well defined. However, people are aware of the risks and hazards of unexpected start-ups and having whole-body access across a wide area, not just around one machine. “One way of getting around this is to have presence sensing,” Edwards suggested. “You can make sure you absolutely know whether there’s someone inside that area. But that can be difficult in large areas with lots of moving parts, lots of shadows and places where you could be hidden. So you then invoke inhibit functions. This is currently only used in US standards, but is being brought over into ISO standards at the moment. “I really like the term inhibit function – it really helps understand the idea,” she continued. “It’s inhibiting the reset function. And you get both proactive and reactive inhibit functions. Proactive means giving personal control to the people going inside a large safeguard in space, maintenance, or teach mode; reactive means escape release or people stopping the machine if you are inside and you realise that the machine is starting up while you are inside!” The discussion then moved on to how to carry out risk assessments, which you can access by viewing the on-demand version of the discussion here: https://drivesncontrols.news/83c3mg The Panel Eve Edwards Commercial Manager Fortress Interlocks Eve, a machinery safety specialist, is a member of ISO TC 199 Working Group 7 – Safety of Machinery – Interlocking Devices, and sits on the ANSI Z244.1 Lockout/Tagout committee in the US. In the past 12 months, she has presented more than 80 Webinars on machinery safety topics, written a monthly newsletter, and co-starred in a YouTube video, “Eve and Malc’s Safety Show”. Martin Kidman, Market Product Manager (UK & Ireland), Safety Solutions Sick Sensor Intelligence After gaining a BEng (Hon) and MSc (Eng), Martin started his career in 1999 working for a notified body testing equipment to the Low Voltage Directive. He took a four-year break to gain a PhD at the University of Liverpool, and since 2006 has been involved in industrial automation, working for various sensor manufacturers. Martin has been with Sick since 2013 providing services, support and consultancy for industrial safety applications. Jason Reed Account Manager, Pilz Automation Jason Reed is an electromechanical engineer who has been involved in the machinery safety industry for more than 16 years, including participation in standards committees. He has experience of projects across a variety of industries and applications and is well- versed in the issues that manufacturing companies are facing and need to consider to comply with the latest safety legislation and standards.