标签: cae

  2013 ANSYS 中国用户大会  “2013 ANSYS 用户大会”于5月22-24日在美丽的海滨城市大连隆重举行。ANSYS中国携手合作伙伴安世亚太公司联手打造年度行业盛会，大会将围绕“聚合的力量”——汇聚CAE领域最前沿的趋势与话题，积聚ANSYS及合作领域最先进的CAE信息与技术，来自结构仿真、流体分析、电磁仿真等不同领域的客户与同行齐聚一堂，开创系统级工程仿真创新发展之路。   ANSYS中国用户大会是世界领先的工程仿真软供应商ANSYS公司中国用户最盛大的节日，是各行各业、不同领域用户经验交流的互动平台，也是与世界行业专家近距离交流的难得机会。   本次会议包括：价值不菲的高级培训；最新ANSYS系列产品体验；世界顶级专家行业视点；用户深度技术交流。参会用户将借此机会全面了解ANSYS公司及技术的最新进展和发展方向，掌获仿真技术在企业创造价值的新视点。      获奖证书 在这里感谢ANSYS中国！   感谢 ANSYS 中国用户大会！

Editor's Note: This "How it used to be" piece was emailed to me by a reader named Glen. I'm still trying to persuade him to send me a pair of "Then" and "Now" photos showing him as a young engineer and as the seasoned professional of today. In the mid '80s my employer was using CAD in the drafting department for PCB layout, but the engineers still drew their schematics with a drafting table, D-size mylar, plastic symbol stencil, HB pencil, and – of course – a pencil rebooter (aka an electric pencil sharpener). The component delete function was performed with an electric rotary eraser. The move to CAE was filled with many highly-frustrating learning curve errors. Workstations that crashed and ate the unsaved schematic when one was too fast on the mouse (the 'fix' was to shut off the cursor to slow down the engineer). Components with hidden power pins that were supposed to automatically connect to power and didn't (or did, but they connected to the wrong voltage). Thousands of text warnings and errors to wade through to find one that was meaningful. Schematic sets that took three hours to print (but could at least be photocopied easily). Compiles that had to run on the same workstation that the schematic was drawn on. I could go on, but suffice it to say the early days of CAE were not easy, and all of these "features" caused a lot of trouble to engineers who were more concerned with the actual electronic design than fighting with cranky system issues. Of course, management thought CAE was a wonderful time saver. However, some things that early CAE did do well after all the compiling bugs were eventually fixed were the back annotation (re-naming reference designators to match physical PCB location), creating the BOM (electronic parts only, mechanical parts were still added by hand), and netlist generation. Especially the netlist generation. Since the drafting folks used CAD, there HAD to be a netlist – they did not look at the schematics anymore. This is how we created the netlist before CAE: First we asked the drafting department to make a set of blueprints of our D-size mylar film drawings. Then we commandeered a meeting room for several days and hung the paper schematics on the walls all around the meeting room. A bunch of engineers would walk around with yellow highlighters and trace out every single net on every sheet, identified by name. One person would sit at a table and write down (yes, by hand) all component and pin reference numbers as the engineers called them out. At the end of several days the final check was to make sure every connection on the schematics had been yellowed, and hope the transcriber had not made any errors. Checking this would have taken almost as long as the original activity. Then after the drafting department had finished the layout we had to perform back annotation. Manufacturing insisted that reference designations had to be in a sequential order on the PCB instead of randomly assigned while drawing the schematics. The drafting department would return a hand-written from/to list of all the new component reference designations which we then had to manually copy to the original schematic mylars. In one case, a colleague went to fetch the list and the draftsperson fished the only existing list out of his wastebasket ( "What the heck do you need this for?" ). The back annotation included any gate swaps that the draftsperson did to facilitate trace routing. Usually was not a problem since it normally did not matter which gate in a package was used. But this is not true for packages in which banks of buffers are tristated through control pins. Fortunately we caught this while transferring the gate swaps to the schematic. ( "But you told me I could swap gates!" ) After final layout we had drafting plot a set of Gerber films for inspection. Ever tried viewing black and clear Gerber plots through each other on a light table? Engineers did not have access to the CAD equipment to view multi-multiple layers in separate colours. Yes, early CAE had its good points as well as bad points. A humourous incident after we went to CAE was that one of the management people told the office admins to stop ordering 0.5 mm pencil leads since the engineers were now using CAE. We quickly got that situation rectified.  

Electronic components and circuits were handcrafted before the 1970s. Circuit diagrams (known as schematics) were drawn using pen, paper, and stencils. Similarly, the copper tracks on a circuit board were drawn using red and blue pencils to represent the top and bottom of the board. Any form of analysis (for example, "What frequency will this oscillator run at if I use this capacitor and this resistor?" ) was performed with pencil, paper, and a slide rule (or a mechanical calculator if you were lucky). Not surprisingly, this style of design was time-consuming, expensive, and prone to error. Computer-Aided Design (CAD) As electronic designs and devices grew more complex, it became necessary to develop automated techniques to aid in the design process. In the early 1970s, companies like Calma, ComputerVision, and Applicon created special computer programs that helped personnel in the drafting department capture hand-drawn designs in digital form using large-scale digitizing tables. Over time, these early computer-aided drafting tools evolved into interactive programs that performed integrated circuit layout; that is, they could be used to describe the locations of the transistors forming the integrated circuit and the connections between them. Other companies like Racal-Redac, SCI-Cards, and Telesis created equivalent layout programs for printed circuit boards (PCBs). Collectively, these integrated circuit and circuit board layout programs became known as Computer-Aided Design (CAD) tools. Computer-Aided Engineering (CAE) Also in the late 1960s and early 1970s, a number of universities and commercial companies started to develop computer programs known as simulators. These programs allowed students and engineers to emulate the operation of an electronic circuit without actually having to build it first. Perhaps the most famous of the early simulators was the simulation program with integrated circuit emphasis (SPICE). This was developed by the University of California in Berkeley and was made available for widespread use around the beginning of the 1970s. SPICE was designed to simulate the behavior of analog circuits – other programs called logic simulators were developed to simulate the behavior of digital circuits. Around the beginning of the 1980s, companies like Daisy, Mentor, and Valid spawned computer programs that allowed engineers to capture schematic (circuit) diagrams on the computer screen. These tools could then be used to generate textual representations of the circuits called netlists that described the components to be used and the connections between them. In turn, these netlists could be used to drive analog and digital simulators (and eventually layout tools). The companies promoting front-end tools for schematic capture and simulation classed them as Computer-Aided Engineering (CAE) . This was based on the fact that these tools were targeted toward design engineers, and the CAE companies wished to distinguish their products from the CAD tools that were originally used by the drafting department. (With hindsight – the one exact science – it would have made much more sense to use CAD to refer to the front-end design tools and CAL to refer to the downstream layout tools ... but it was not to be... Oh well, that's the way the cookie crumbles...) Designers vs Engineers If you say things the wrong way when talking to someone in the industry, you immediately brand yourself as an outsiderÿ– one of "them" instead of one of "us" (and you certainly don't want to be "one of them" (grin). For historical reasons that are based on the origins of the terms CAD and CAE, the term layout designer or simply designer is typically used to refer to someone who lays out a circuit board (determines the locations of the components and the routes of the tracks connecting them together). By comparison, the term design engineer or simply engineer is typically used to refer to someone who conceives and describes the functionality of an integrated circuit, printed circuit board, or electronic system (what it does and how it does it). Electronic Design Automation (EDA) Sometime during the 1980s, all of the CAE and CAD tools used to help design electronic components and systems came to be referred to by the "umbrella" name of Electronic Design Automation (EDA), and everyone was happy (apart from the ones who weren't, but they don't count ).