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Schematic layout in plain CAD, do you still do it?

Catwell
When it comes to schematic layout, element symbols, wirejump techniques, and other practices inside all the companies I have ever encountered, there seems to be no standards. For example, one fire protection company I worked with had real messy drawings. When you would zoom in to wire junctions, the lines did not actually meet, in many cases. It made me ask several hundred times, if that was on purpose. I discovered that many of the symbols used for various components, such as a relay, were just made up by the same person who drew lines that didn't connect. All this made it incredibly difficult to analyze. And, in an industry where people's lives will ultimately be protected by this sloppy engineer's schematics, they were all OK with it. Turns out, the resident "senior" electrical engineer was the only one drawing these schematics. It made me wonder, where was this person trained in schematic layout?

Looking back to the companies I have worked for, it seems that they all had their own slightly different way to design and draw circuits. The fire protection being the most extreme example non standard layouts, though.

Most of these odd drawing I've had the pleasure in trying to deduce, were all drawn in a basic CAD system, not OrCad or EagleCAD, which has standard symbol libraries, or hand drawn on plain old paper.

My question is, does anyone use CAD to draw their schematics? Do you draw your own symbols? And most importantly, were you trained in doing so, or like a lot of us, just learned on the fly? I know that the engineers that hand drew schematics trained for it in college. But, more recently, I do not see schematic layout as a college requirement. I find that a bit troubling.


I must admit, I still often find myself drawing some circuits in a plain CAD program.


Cabe
  • 0

    I don't design anything anymore professionally, but in my previous workplace, even we used sophisticated software for designs, I used plain cad (standard AutoCAD) to draw most of the schematics. Reason for that was in the size of design and that the more advanced software simply didn't allow me to draw the whole schematics on one sheet, but I had to make blocks, which only confused guys assembling the PCB later on image

     

     

    For personal designs, I still use the old fashioned pencil and rubber and squared paper - oddly enough, I find it faster than PC (not for a PCB layout though!)

  • 0 in reply to Former Member

    Vojtech,

     

    It's a shame that traditional drafting isn't a required class anymore. I think it's important to experience how it used to be before going into the computer aided level. It's like learning assembler before moving to higher languages.

     

    Cabe

  • 0

    As an electrical engineer I used AutoCAD with my own library of symbols, this was convienient since I could quickly generate new symbols on the fly, however as a electronic design engineer I found even a small design prototype is better simulated first (Providing you can get all the simulation models), for my Analogue Design back then Microsim was industry standard (later became OrCAD), as the simulation and PCB drafting was fast, stable and offered a quality HCI (Though not the most modern looking interface!).

    Now I am on a technical team, I notice quite a few of our customers use PCB editing only packages, some designs do not need to be simulated such as esoteric designs, small circuits, and some pure digital circuits where the main part is the coding; and so they prefer to build and test prototypes using a cheap PCB editing package.

    However sending a product out to market with medium complexity without being properely simulated first can lead to disaster, why?, prototype testing is a lengthy and costly process, advanced tests such as temperature sweeps, Monty Carlo and worst case analysis can be done on the fly during simulation, however real world testing on these is either impossible or painfully slow. Companies using simulation as a matter of routine during the design phase will have less defects during manufacture and lengthened Mean Time Before Failure (MTBF).

     

    I never had training on any package, everything has to be learnt on the fly in demanding engineering environments, unless the company is large enough to absorb the training impacts, so its important that the human computer interface (HCI) is easy to pick up and run with.

     

    Would people like to share their AutoCAD symbols on here?