Asset Utilization Metrics Propel a Revival in Safety Solutions
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The document discusses advancements in safety solutions within manufacturing, highlighting a shift from hardwired systems to more effective and flexible programmable safety PLCs. It emphasizes the benefits of these new technologies, such as reduced costs, improved diagnostics, and enhanced asset utilization, while underscoring the importance of meeting safety standards to minimize workplace accidents. Recommendations are provided for manufacturers to evaluate available safety system options to optimize their operations.
Asset Utilization Metrics Propel a Revival in Safety Solutions
- 1. THOUGHT LEADERS FOR MANUFACTURING & SUPPLY CHAIN ARC INSIGHTS By Sal Spada & Dick Slansky INSIGHT# 2003-27MD JULY 16, 2003 A new generation of safety solutions have emerged that are more effective in preventing accidents, less costly to implement, more easily to adapt, more reliable than existing hard wired systems, and results in an increase in Overall Equipment Effectiveness. Asset Utilization Metrics Propel a Revival in Safety Solutions Keywords SafetyBUS, Safety PLC, Fieldbus, Automation, Machinery, OEE, Real-time Metrics, RPM Summary Health and safety in the workplace has not always been a primary consid- eration in manufacturing environments. However, there is a renewed interest in safety emanating from Europe, highlighted by the European Norm standard EN 954-1, which is garnering in- terest in Japan and North America. Safety technology has progressed considerably since the first emergency stop relay appeared on the mar- ket, and the future will bring new developments to this technology. Improvement in the imple- mentation of current safety standards is mutually beneficial for the protection of both man and ma- chine with the reduction of workplace accidents, lost output, damage to machinery, and insurance premiums while resulting in an increase in Over- all Equipment Effectiveness (OEE). Manufacturers are currently re- evaluating the safety aspects of their machines and devices so as to provide the safest possible workplace environment. Analysis Today manufacturing organizations are changing the way they think about safety systems on the factory floor. What is transpiring is a new generation of solutions designed to be more effective in preventing accidents, less costly to implement, easier to adapt, and more reliable than existing hard wired systems. Internal engineering organizations are simply changing the way safety systems are designed. Manufacturers are seeking to optimize the use of existing assets with solutions that drive toward maximal uptime and offer a greater amount of flexibility over traditional hard wired solu- tions. Accidents themselves can lead to substantial downtime. Nuisance trips are not as costly, but generally require a complete audit to identify the
- 2. ARC Insights, Page 2 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com source of the problem. Although operators have the best of intentions, there are issues associated with tampering or overriding safety systems that factory managers are addressing as well. Safety PLCs Mirror the Benefits of Standard PLCs Modern day safety solutions are mirroring similar features and benefits paved by first generation PLCs. More specifically, the primary benefit that the first generation PLC brought to the market was the substitution of hardwired relay logic with a programmable software based solution. These systems utilized the same language that electricians were already using, Relay Ladder Logic, which enabled this new technology to be readily acces- sible to end users without requiring new skills. This effectively revolutionized the way machinery was designed and electric panels were laid out. The PLC did not make inroads into operator safety circuits. Thus, the majority of safety solutions protecting operators from machine hazards are hardwired relay solutions that consume a significant amount of panel space and are costly to install as wire must be routed throughout the machinery or a work cell. The Safety PLC, being distinct from a standard PLC, is now a primary focus of engineers planning to re-engineer safety sys- tems. In the past, standard PLC controllers used in safety applications were configured in pairs. Redundancy was re- quired to provide a safe and orderly equipment shutdown in the event that the primary PLC failed. These multiple control- ler configurations also required additional I/O, custom software, and hardware to support the safety portion of the automation ap- plication. By contrast, safety systems designed around Safety PLCs take a completely different approach to the safety control issue. Rather than employing re- dundant PLCs, the Safety PLC incorporates redundant CPUs into a single PLC chassis. This integrated approach reduces the additional I/O, hard- ware count, and specialized software required for redundant safety systems. The Safety PLC is now enabling efficient solutions by substituting software for hardwired relay logic as well as employing a robust, fault tol- erant networking technology. More specifically, the safety PLC is regarded as a preferred solution over existing hardwired solutions despite the per- ception of being more costly. When considering all the factors that drive Benefits Safety PLCs replace hardwired relay logic with a programmable software solution Integrated Safety PLCs reduce redundant I/O, custom soft- ware, and hardware. Reduced cost and complexity provides lower Total Cost of Ownership Benefits of Safety PLCs
- 3. ARC Insights, Page 3 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com the Total Cost of Ownership of a safety solution, the additional initial costs are quickly negated. The benefit of radically improved diagnostics with Safety PLCs and the lower cost of interconnection versus a hardwired solu- tion are very apparent cost justifications. Machine Builders and Engineering Organizations Evaluate Safety Fieldbus Solutions Engineering groups in a broad range of industries, such as Automotive, CPG, and Metal Forming have evaluated safety architectures that are based on Safety PLCs. The general consensus on Safety PLC architectures is that: • Engineering labor costs are lower, • Deployment of systems is easier, • Capital costs are lower, • Panel space is radically reduced, and • Drives organizations to develop common implementations. In particular industries that are moving toward more modular assembly lines as opposed to long continuous assembly, the use of a Safety PLC will prove to be very advantageous. The use of an intelligent safety device al- lows for the lines to be reengineered and integrated rapidly without having to incur the high cost of rewiring an entire line. Effectively, each modular cell is monitored by a single Safety PLC. Safety functionality in machinery or production lines is very expensive to implement today with safety switches. Machine builders specifically are looking at the Safety Fieldbus solutions to implement safeguards around their machinery. Fieldbus networks are widely used for transmitting control data, but this does not include safety related data. Conventional fieldbus networks are not suit- able for safety systems, since additional error detection and avoidance mechanisms are required. An independent safety layer is necessary to detect connection or device fail- ures and react with the appropriate action such as an emergency shutdown to avoid harm to operators and as- sembly personnel. Safety Fieldbus offers significant advantages over tradi- tional hardwired safety systems. Machine safety circuits for robots, presses, and other assembly machines are less Benefits Independent safety layer provides failure detection and error reporting capability that conventional field- buses lack Provide intelligence for Asset Man- agement at the machine/device for OEE, Machine Condition Monitoring, & Diagnostic applications Better implementation of safety standards reduces workplace acci- dents, lost output, damage to machinery, and insurance premiums. Benefits of Safety Fieldbus
- 4. ARC Insights, Page 4 ©2003 • ARC • 3 Allied Drive • Dedham, MA 02026 USA • 781-471-1000 • ARCweb.com complex with fewer cables and connections, which in turn reduce design and installation costs. Additionally, where intelligence is distributed to the machine level, asset management applications such as diagnostics, machine condition monitoring, and OEE are available. This will enable a much faster reaction to fault detection and rectification, resulting in an overall improved maintenance environment. It is not only scheduled maintenance and mechanical failures that are cause for machine downtime, but operator accidents and nuisance trips of hard wired safety systems that wreak havoc on a company’s OEE metric. Standards Sought for Safety Solutions Although there are a number of solutions available on the market from ma- jor automation suppliers such as Pilz, Rockwell Automation, and Siemens, standards continue to lag. Fieldbuses employed in safety-related applica- tions are required to adhere to international standards, such as IEC 61508 for programmable safety systems or industrial specific implementations. The lack of standardization in safety networking is delaying the introduc- tion of devices that can be distributed over a safety networking architecture. Users on the forefront of implementing safety architectures are envisioning a move toward devices that incorporate safety directly to achieve a zero space enclosure. Ideally, users want standardization in pro- gramming software and networking to fulfill current in-house initiatives. Recommendations • Manufacturers evaluating implementations of current safety standards for their production operations should be aware of the various options for safety systems and the state of the current technology. • Major automation suppliers now offer safety solutions in various forms such as Safety PLCs or Safety Fieldbuses. Users need to carefully evaluate the options for best fit for their operations. Please help us improve our deliverables to you – take our survey linked to this transmittal e-mail or at www.arcweb.com/myarc in the Client Area. For further information, contact your account manager or the authors at sspada@arcweb.com or dslansky@arcweb.com. Recommended circulation: All MAS-D clients. ARC Insights are published and copyrighted by ARC Advisory Group. The information is proprietary to ARC and no part of it may be reproduced without prior permis- sion from ARC.