At 09:19 PM 2/5/2002 +0000, Steve Wiseman wrote: > > Elsewhere I described an alternate method of doing a virtual short, that > > is, a jumper footprint that appears as open to DRC but is actually shorted > > in plot. This alternative involves placing a track, as part of the VS > > footprint, on an otherwise unused mech layer. > >I used to do this, and still do sometimes for jumper links. However, it's >extra steps at photoplot time, and extra steps = extra opportunities for >mistakes. Since, by the time a board this complex goes out, I've normally >been working 20-hour days for a week, the simpler I can make things, the >longer the PCB shop will let me sleep before phoning for clarification :)
It is one extra step, which does not need to be repeated. This is one great feature of the CAM Manager: you can set up individual parameters for each plot if you want, and then all [enabled] plots will be generated at once. Usually we don't need to do this, but making such a shunt is a case. I also use this feature to generate formal drawings, merging a different mech layer. Remember, if you *do* forget to short the part, it is not a big disaster, if you have made the parts properly. You might even do both: a virtual short and a shunt. That is, take your current virtual shorts and add mech layer track to short them. If we had layer associations it would help. (Top is associated with Top Overlay, so when you flip the board, the overlay flips with it. That doesn't happen with the mech layers, which is a Protel deficiency. Tango DOS had top and bottom assembly layers in addition to the legend layers, they flipped with the part....) Thus one should make a top layer shunt and a bottom layer shunt, and they should not be flipped in design. Protel should, in general, fix the photoplot routines so that WYSIWYG, without *any* deviation except the unavoidable one of roundoff error. There is little reason for aperture matching in times when the plotters can handle D-codes to D999. I'd make aperture matching an option that defaults to zero. *Maybe* I would accept minimum aperture matches that represent only the minimum difference resulting from unit shifts (mm-mil). But I think not. By the way, it's pretty obvious why the rotated pads did not plot. The plot routine quite properly does not draw pads or any other primitive with a zero aperture unless zero is the actual size of the primitive. The programmer trapped it out, it would lead to lockup. [EMAIL PROTECTED] Abdulrahman Lomax Easthampton, Massachusetts USA * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
