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By Joe Lazzara, President & CEO, Scientific Technologies Inc.
What are some of the key future trends that will be significant drivers of the machine and automation markets? What will be changing the shape and practices of the machine safety and guarding industry? Well, get out your crystal ball, your Ouija board and sit down for a séance ‘cause here we go…
Trend: Globalization of US Standards
As we have in the past few years, we will continue to see the trend of globalization and the rapid pursuit of common, international standards for machine safety. Clearly, Europe has been driving this effort. The U.S. is still lagging in the trend toward harmonization of U.S. and International, or should I say, European standards. European standards, typically EN documents, have become a virtual farm league, or proving ground for the international standard bodies, such as IEC. Of course, this transition from EN to IEC gives the European machine builders a jump over their non-EU competitors.
The trend of U.S. progress toward standard globalization falls into the category of two steps forward, and one step back. For example, there are likely to still be standards, such as the U.S. National Electric Code that may never be fully harmonized internationally. This could leave machine builders with the dilemma of continuing to manufacture separate domestic and international version of their products, or abandon the international market altogether to those competitors supported by lower valued currencies, such as the Euro.
Trend: Earlier Safety Integration in the Machine Design Cycle
Looking beyond the standards globalization issue to more specific technological practices, is the trend of earlier safety integration into the machine design cycle. Clearly, the risk and safety considerations of a machine are being evaluated and mitigated earlier and earlier in the design cycle. The days of "We are almost finished, let’s throw the safety guards on" or worse, leaving the safety issues for the customer to resolve are certainly over. With this trend, safety becomes an integral part of the machine control – and we will see how technological advances are making this process almost seamless. Another benefit of an earlier safety design cycle is improved accessibility and machine esthetics, which means cleaner designs with better maintainability.
Trend: More Intelligent Safety Controls, Less Safety Relays
Next is the trend of more intelligent safety controllers, such as safety PLCs, which will reduce the usage of the electromechanical safety relay modules. These modules have been the backbone of safety control design for decades. They are easy to use, have predictable failure modes, and are offered with a wide variety of functions. Unfortunately, they are mechanical devices, consume energy, panel space and often require that all safety devices, such as safety interlock switches, be wired back to a central panel. Customers have welcomed the availability of solid state safety devices, safety PLCs and safety rated communication buses. From STI’s perspective, all of our new safety light curtains are available with solid state outputs. It is very convenient and cost efficient, especially when the light curtain is connected directly to a safe PLC, and thus eliminating the need for several mechanical relays.
Trend: Safety Rated Buses
From the next industry trend will emerge the use of safety rated communication buses or networks. I believe the emergence of these safety rated control networks will decrease the popularity and usage of the safety relay module. It will also be a major force in the further integration of safety and the machine controls into one seamless control system. Let’s look at an overview of these safety networks.
In order to understand the impact of the safety networks, let me first explain how safety devices are typically installed. Usually, they are individually hard-wired, or alternately daisy chained in series back to an emergency stop system or to a machine primary contact or motor starter. Series-wired, or "daisy chained" wiring, saves on installation costs, but are difficult to troubleshoot. For example, which mechanical guard may not be fully latched? Like their non-safety brethren, the beauty of the safety rated control network is that with less wiring, a specific device can be identified and the problem diagnosed.
Unfortunately, early versions of these such as Safety Net from the United Kingdom, were not integrated with a machine’s control bus, and were not supported by the global automation suppliers. These factors resulted in little market acceptance.
The newest versions of safety networks have integrated the safety and control system as one common unit – there is no need for a separate safety bus, or safety PLC. This saves costs in design, materials and installation. ASI bus, sponsored by Siemens and others, is one version of a safety rated bus, and is called "Safety at Work." ASI stands for actuator-sensor-interface. Two such buses, ASI and ProfiSafe are currently available for sale, with others, such as Device Net Safety from Rockwell and CANOpen Safety from a European consortium, still under development. All of these were adopted from existing control networks, with the safety functions added on through extended system architecture and hardware.
Trend: More Intelligent Safety Devices
The trend of more intelligent safety devices is a natural component of the safety control bus evolution. The use of a safety bus requires more intelligent safety devices with capabilities beyond the simple on/off or open/close outputs. Specific versions of common safety devices such as interlock switches, e-stop or emergency stop push buttons and light curtains would be available with the appropriate bus communications protocol and thereby provide improved diagnostics. No longer on a large, complex machine or manufacturing cell would a maintenance employee have to dash around trying to determine which gate or guard was not fully closed, or which e-stop was pulled. This increased intelligence and diagnostic capability translates into less machine downtime and, therefore, higher productivity.
Trend: More formal risk assessments/risk reduction
The next trend involves a more formal risk assessment and risk reduction program. There are two fairly recent standards, which espouse the advantages and methodology of risk assessment. The new robot standard, RIA 15.06-1999, is a good example. The ANSI B11 technical report on risk assessment, TR3, is still under development, but is close to completion. I have heard from those associated with the TR3 Committee that this work has taken a somewhat different, and they believe better, approach than the European based standards on risk assessment. There are also differences between the robot standard and the ANSI TR 3 standard as well. Unfortunately, this again means that the U.S. standards are not completely harmonized with the international standard IEC14121 on risk assessment, although they are similar. The trend of doing a more formalized risk assessment program will help ensure that machines are designed with the safety and integrity of the machine in mind at an early stage in the machine's development.. However, we are making progress and I view the movement toward a formal risk assessment as a positive trend.
Joseph J. Lazzara is President and CEO of Scientific Technologies, Inc ("STI"), the largest provider of automation safeguarding solutions in North America.
Joe is the Chairman of the Safety, Health and Environmental Committee for the Association of Manufacturing Technology (AMT). He is also a member of the Board of Directors of the American Electronics Association (AEA), the nation's largest high-tech trade association.
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