标签: safety

All of us are susceptible to attention lapses, and they can range from minor annoyances like losing your focus on a book you are reading to making mistakes in figures you are adding or forgetting that you left a pot boiling on the stove until you smell something burning.   But attention lapses while driving a car are always dangerous, and are becoming more so now in vehicles equipped with infotainment systems with multiple displays.   Much of what the driver sees in these displays is categorized as “driver aids”. They include maps for navigation, automobile engine status, weather information, distance to destination, and a camera view of the road behind you. Sometimes there is a cellphone built in, adding yet another display, or an attachment that projects a smartphone display in a vehicle's front window so you can drive and check your email at the same time. But few of them help you to keep your attention where it should be: driving and traffic conditions.And all it takes is a few seconds and sometimes much less to find yourself in trouble. Think about it: An automobile weighing anywhere from 700 to 1,200 pounds at a minimum, traveling at 60 miles an hour translates into 80 feet/second. Even on a lightly traveled freeway most cars travel closer to the car ahead than that 80 feet. And vehicles in the next lane are only a matter of five to ten feet away. Not a lot of room to avoid serious problems in the second or two (and often much less) that you have to take action.   That there have not been more vehicle deaths and serious injuries associated with such “improvements” I think is due mainly to the strengthening of the vehicle frame and the electronics built into the engine and auto body framework.   Better late than never, the U.S. National Highway Traffic Safety Administration (NHTSA) in 2010 initiated a program to take a closer look at the problem of distracted driving. One of the results was a set of guidelines in 2013 with recommendations to follow, including: - The distraction induced by any secondary task performed while driving should not exceed that associated with a baseline reference task such as manual radio tuning. - Any task performed by a driver should be interruptible at any time. - The driver, not the system/device, should control the pace of task interactions - Displays should be easy for the driver to see and content presented should be easily discernible   Risk factors due to information overload in modern automotive infotainment subsystems. (Source: U.S. National Highway Traffic Safety Administration (NHTSA))   But even these relatively modest recommendations are unevenly deployed, and where followed are open to broad interpretation.   The NHTSA also recommended that tasks/devices not suitable for use while driving should be locked out from the driver's control, including device functions and tasks not intended to be used by a driver while driving, such as manual text entry and smartphone and network activities such as texting, chatting, and internet browsing; displaying video and images, and scrolling text. It also recommended locking out the display of books and social media content.   However, on the various business trips where I have used rental cars, I have not seen any cars with the sort of “lock-outs" talked about in the report. And therein lies one of the weaknesses of the recommendations: they do not have the force of law. Another is how little attention is paid to our ability to do multitasking and task-switching in an automotive environment.   Eyes on the road We humans are good at multitasking, which is the ability to handle a mix of unrelated actions at the same time. When you eat your dinner while simultaneously carrying on a conversation and listening to music in the background, you are multitasking.   But we are terrible at task-switching. This occurs when you redirect your attention and cognitive energies from one task that requires total attention to another unrelated task that also requires total or near-total attention. When you are driving and shift your attention to the infotainment navigation display, you are less able to notice and react to changes in traffic: a stoppage of traffic ahead, a pedestrian stepping into the street, or a car that switches lanes in front of you.   One cognitive researcher who has looked hard and long at switch-tasking in particular is Clifford Nass of Stanford University , initially in the context of mobile phone users, particularly teenagers . He found that a majority of teens are routinely using three or more media at one time, even while driving a vehicle.   Nass found that as a result of such switch-tasking they had profound problems related to the ability to filter information, manage working memory, and difficulties in switching from one task to another. Each of these deficits had enormous implications for mobile phone users when driving under both normal and complex circumstances.   Concerned about the proliferation of electronic devices to distract drivers, Nass recently started a lab at Stanford that focuses on how the information environment in the car can lead to a series of “attractive nuisances” that undermine driving performance. This includes not only the entertainment systems, but the warning systems, navigation systems, and other aids and how those varying tasks and sources of content are managed or mismanaged by drivers.   It will be interesting to see what the lab comes up with. From my personal perspective, these things are not being managed very well, either by the drivers or the auto makers who continue to ignore even the NTSA's modest recommendations. Until more research emerges and more common sense is applied by manufacturers, I have taken a minimalist approach.   I own an old car that has no infotainment aids, forcing me to keep my eyes on the road and my mind on driving. It might not be as much fun as driving with an infotainment system installed, but I have much more confidence that I’ll get where I’m going in one piece.

"Ground" is one of those terms that gets tossed around so much in our profession that it has an almost mystical-like aura. It seems that whatever your design topology, you need a good, solid ground to solve your problems—except, that is, unless you really don't want a ground, and instead you need isolation. Not so simple, is it? By "ground" here, I am not referring to a signal or DC rail "common" connection (return path), which is often mistakenly called out as "ground." I am referring to a true ground that is associated with AC power lines with a direct connection to Earth. It functions as a near-infinite source and sink for excess electrons, which also can result in a near-zero voltage between chassis and another similar point—more precisely called the "potential difference." Where would we be without ground? The answer is: it depends. The dilemma is that sometimes you want to make sure everything is grounded, via solid, low-impedance connections to the Earth, for either user safety, system performance, or both. But then there are other times where that same Earth ground is something you actually don't want, in order to achieve those same objectives. Think about a basic power tool: Are you going for a product with two-wire AC-plug and using a double-insulated case, or one with a three-wire AC plug and a grounded metal case? (And where is the "ground" on that airplane, anyway?) The ground issue becomes complicated when you are trying to isolate a circuit that eventually connects to an AC line and its associated ground. The easiest way to isolate your system from the line ground is via a transformer, which is a reliable, well-understood, and well-behaved component. But there are times when you need to instead isolate your AC-powered circuit in its DC and electronics subsection, and that brings new options and new issues. It also means you have to be careful to isolate not just power, but also any signals, as a non-isolated signal path can negate the benefits of an isolated AC line. If you think the issue of grounds and grounding is straightforward, think again. There's no shortage of papers and guidelines on the subject, as well as the various electrical codes of different countries and even local municipalities to consider. The recent posting " When Good Grounds Turn Bad—Isolate! " by Thomas Kugelstadt, a Senior Applications Engineer and prolific author at Texas Instruments, shows there is always room for more insight and understanding. Back in the days when there were products that used only line-AC internally—say, a heater connected to the power line—it was easier to decide on your grounding approach. Now, even basic AC-connected products have internal electronics, AC/DC supplies, and even connectivity ports, so new challenges arise. Unless you design exclusively in the world of battery-powered, handheld, non-chargeable devices—and yes, there are lots of those—sooner or later, the issue of grounding will come up with questions such as "Do we ground?" "If so, where do we ground?" "How do we ground?" "Maybe really want isolation, instead?" Grounds and grounding may seem like mundane topics for low-voltage designers, but eventually, many of these low-voltage rails work their way up to an AC line and the real world. It never hurts to understand how Earth grounds affect your product design, performance, and safety. Perhaps you need to take a break from the world of low-levels signals, fast slew rates, and other attributes of today's circuits, and review those basics—and reexamine them in a new way. What's your experience with grounds, grounding, product safety, and product performance? Have you ever been stung, both literally and figuratively, by AC-ground problems?  

近日，TUV 南德意志大中华集团向中国航天电子技术研究院北京航天微机电技术研究所（以下简称航天所）颁发了国内首张安全继电模组功能安全证书，该款“航安”SRM 2S$20D24A安全继电模组在获得功能安全认证证书之后，可以满足SIL3, PLe, Category 4的安全等级。该证书的颁发，标志着国内安全继电模组产品完全可以满足国外苛刻的安全要求，可用于紧急停止控制和安全门的监控，能够广泛用于注塑机、数控机床、轧钢机、卷板机、包装机械、玻璃成型机、电梯等多个领域，再次证明了民族品牌完全拥有与传统外资强势品牌同台竞技的技术实力。 2011年8月3日， 北京航天微机电技术研究所在北京成功举办了其自主研发的安全继电器系列新产品发布会。T?V南德意志集团作为特约嘉宾出席，并见证了“航安”安全继电器系列产品的市场发布会。“航安”安全继电器是国内率先通过T?V功能安全认证和欧盟CE认证的安全继电器产品。 “航安”安全继电器依托航天高可靠技术积淀，借鉴国外功能安全先进理念，关注机械安全和劳动者安全保障，安全继电器产业对注重以人为本、人与机器和谐共存、可持续发展具有重要意义。与会嘉宾对新产品表示高度认可和大力支持。来自北京第一机床厂的嘉宾表示，“航安”安全继电器获得T?V功能安全认证和CE认证，具备了出口欧洲的技术条件，在今后的机床电气设计中会重点考虑采用“航安”安全继电器代替国外品牌。来自大连橡胶塑料机械股份有限公司的嘉宾对“航安”安全继电器获得T?V认证表示祝贺，希望双方加强交流，深入合作。自动化行业代表也纷纷表示愿与“航安”安全继电器一起创造中国功能安全的美好明天。 TUV南德意志大中华集团秉承多年来在功能安全领域内的技术经验，以及世界领先的第三方测试与认证机构的检验能力，圆满的完成了为航天所自行研发设计的安全继电模组产品提供认证服务任务。由于安全继电器产品对于整体开发流程，产品可靠性等方面的要求较高，早期只有少数外资品牌(如西门子、皮尔磁等)才拥有类似的产品，目前在国内也仅仅只有少数几家拥有较强研发能力的机构在进行相应的开发工作。项目正式开始前，双方经过充分的沟通与讨论，该项目进展比较顺利，国内第一张安全继电模组产品功能安全认证证书的颁发，为航天所安全产品的市场推广活动铺平了道路。双方在未来将在首张证书颁发的基础上，开展更深入的战略合作。 关于北京航天微机电技术研究所 北京航天微机电技术研究所是中国航天科技集团公司第九研究院（中国航天电子技术研究院）专业从事机电组件新产品开发、新技术孵化的专业研究所，北京航天微机电技术研究所始终关注功能安全整体解决方案。该所一方面非常重视产品研发、细化产品线;另一方面不断加大对安全产品的优化力度，深入挖掘安全光幕、安全地毯等产品的配合需求，力求为客户提供更专业的产品和个性化的定制服务。 继承航天高可靠技术的智慧精华，采纳国外功能安全领域的量化方法，北京航天微机电技术研究所承诺将以中国航天一丝不苟的钻研精神、雄厚专业的科研实力，锐意创新，不懈努力，为广大客户源源不断地提供高质量、高标准的功能安全产品。“航安”安全继电器，必将成为推动中国功能安全行业发展的强大动力。 http://www.biaet.com 关于 TUV 南德意志集团（ TUV SUD ） TUV 南德意志集团于140年前在德国成立，是全球领先的技术服务公司之一，服务范围覆盖测试、认证、检验、资讯及专家指导等多个领域。公司在全世界拥有600多个代表处，员工约15,000人，着力为客户提供技术、体系及实际运作中的优化服务。TUV 南德意志集团在中国的业务开展已有近20年历史。至今，已为10,000多家客户提供了相应服务。 TUV SUD 作为专门提供功能安全认证的第三方认证机构，为SIEMENS，ABB，Pilz，HIMA,OMRON ,E+H, 倍加福，Fisher, 基恩士，美国班纳等国际知名公司都颁发过相应产品的功能安全证书。