Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
At 12:08 AM 1/18/2003, Robert M. Wolfe wrote: Abd ul-Rahman Isn't this just really saying the silkscreen IS the defining factor No. The extents of the footprint are the defining factor in 99SE, if I am correct -- I didn't check it. Often the silkscreen is the outermost primitive. IMHO the silkscreen layer should never have been used as an indicator or ultimately the real extents of a part. There really needs to be a user defined layer that will be used at the extents of a part to check part clearance. Yes. I think that's what I wrote. And that layer does not necesarily have to be an assembly layer. There is no such thing as a P99SE assembly layer. There are only mechanical layers, which the user can personally define as assembly if desired. I have seen systems that define both actual part and real world clearances required for assembly/test/rework etc., and control over which rule pending level of technology required for design. Let me guess. What did those systems cost? And line widths really should have nothing to do with it when you are defining a clearance just center as if it were a zero width line. Yes. Again, this has all been said not only in this thread but before. Only silkscreen itself should be considered for thickness itself with respect to all other features. But part clearance should be to a dimension MMC, etc not ever dealing with the thickness of a line defining it. Of course. Now, to do it at present -- sort of -- , use a mech layer to create a clearance layer with zero width lines (yes, Protel will display them at one pixel) at MMC. Make this a part of all footprints. Do not allow silkscreen lines or any other primitive to extend outside this area. The present clearance rule will only report real collisions (assuming that all parts are rectangular in maximum extent.) This will not work perfectly, but it would work for most parts. And with the DXP additional rules, it will work even better. But it would still be better to check for line intersections between different footprints on that clearance layer. And the huge problem with this solution is that one would have to rework all footprints. Protel's way of dealing with this can of worms was to use the component extents. This was a quick-and-dirty solution, almost better than nothing. The mistake was in using true primitive extents (which goes to the outside of outlines) and/or in not allowing negative clearance. Probably better to have used line-center for the silkscreen portion of the extents instead of line-edge as they did. There isn't really a need for negative clearance except as a compensation for the first mistake DXP then adds the exception rules which allows one to disable checking for particular parts, so that, one, for example, could place one part under another while suppressing the collision error. The comment made by one writer that they would rather see 100 false error messages than miss one real problem (or something like that) misses the point. If you see 100 false error messages you are very likely to miss the one real error. What are you going to do the next revision? Check every one of those 101 errors again? This is why, in my opinion, good design requires killing all the phoney ERC reports in schematic; preferably one designs so that the error reports don't come up, but where that is impractical one suppresses them with a No-ERC Directive. In PCB one can do something like this, sometimes, with a special rule. We have asked for better special rules, perhaps a PCB equivalent of No-ERC, which is truly generic, it will suppress *any* error report. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
Can't you set a negative clearance for this problem? Work out your overlay line thickness and then set the component clearance to -(thickness/2) This should work, though it is untested I tend to turn off component clearance check too, it is annoying. And really, as long as the copper clearances are OK then your design should be alright, as long as you don't accidentally place any component under any other component. Also, there are three types of clearance checking. Quick check and multilayer check are both a bit retarded, full check is still not so great, but seems a lot better to me. As far as what a clearance of 0 should mean, I actually think that Protel is corrrect, as if the outer edges of two components are just touching, there is a clearence of 0 which is what you've specified!! Julian -- Julian Higginson - Design Engineer - Lake Technology. 502/51-55 Mountain St, Ultimo, NSW, 2007, Australia. mailto:[EMAIL PROTECTED] - http://www.lake.com.au -Original Message- From: Brad Velander [mailto:[EMAIL PROTECTED]] Sent: Saturday, January 18, 2003 6:49 AM To: 'Protel EDA Forum' Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6 . John, adding to Jami's list. 5) Do as I do, turn off the component placement DRC check completely. It just doesn't work in any usable manner. Use your eyes and personal knowledge. The component placement DRC uses any land pattern item, visible, invisible, regardless of layer to determine the maximum extent of the component. It then draws a bounding box around all these items, this constitutes the component boundary for the placement checking. Therefore any designator, comment, text string, etc. gets included with the actual desired component boundary. As you have found setting 0 allows placement down to touching but will still show a violation if items actually touch. I too think that this is a failing of Protel/Altium, a setting of 0 should allow items to touch. It probably should allow overlap as well but I wouldn't push it that far because I don't see that being really useful or a common need. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com -Original Message- From: John Branthoover [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 9:57 AM To: Protel EDA Forum Subject: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. SNIP What am I doing wrong? Any information that you can give will be greatly appreciated. Thank you for your time and have a nice day. John Branthoover: Electrical Design Engineer : Acutronic R D:Phone (412) 968-1051 640 Alpha Drive :Fax(412) 963-0816 Pittsburgh PA 15238 :Email [EMAIL PROTECTED] USA :WEBhttp://www.acutronic.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
On 09:40 AM 20/01/2003 +1100, Julian Higginson said:
Can't you set a negative clearance for this problem?
Work out your overlay line thickness and then set the component clearance to
-(thickness/2) This should work, though it is untested
No, negative clearances do not work.
I have been encouraging Altium to implement negative clearances for a while
now. However, I suspect that if they did address this it would be part of
a much more elaborate system that would link into the 3D stuff - component
clearance is after all a 3D issue in some cases. I don't know anything
that you don't about this - just a guess.
DXP has a sort-of-solution that is OK for me. The more elaborate rules and
queries allows you to turn *off* component clearance checking between just
the two (or few) affected components, without preventing clearance checking
between all the other components (and in fact between all the other
components and the two affected components). This is done by using a rule
that excludes checking between these components rather than trying to make
a rule that pertains to just these two components. In other words instead
of an ALL-ALL rule you have a rule that is something like
Not(InComponentClass('OverlappingStuff')-Not(InComponentClass('OverlappingStuff')
rule, where 'OverlappingStuff' is a component class you have set up
containing just the components that you want to allow an overlap on. If
you don't follow don't worry - it would be obvious enough to those at all
familiar with DXP.
I would prefer, though, that the DXP was modified to accept and check
negative clearances in the interim. In most cases this would be sufficient
- full 3D modelling is not required all that often. I would not expect to
see P99SE updated to accept negative clearances, whoever nice it may be.
bye for now,
Ian Wilson
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[PEDA] A Question About PCB Design Rules..... Protel 99SE SP6.
Hello All, I have two (2) position jumpers with a rectangular silkscreen drawn around them. I want to place them on my PCB such that one side of the silkscreen overlap. I created a component jumper class and added these two jumpers. In the design rules under Placement, Component Clearance Constraint I set up a rule for the jumper class to have a gap of 0 mil with scope A and B both set to the jumper class. I did this thinking that it would allow me to place the jumper side by side with the silkscreen s on one side overlapping while not affecting other components. I also left the default Component Clearance rule in place - 10 mil gap with scope A and B set to board. When I attempt this I get a violation as soon a s the silkscreen over lap. If I un-check the On-line Component Clearance check box (under Design Rule Check), I stop getting the violations. How ever, if click on the Run DRC button, I still get a violation. Of coarse this also goes away when I un-check the Report Component Clearance check box also under Design Rule Check. What am I doing wrong? Any information that you can give will be greatly appreciated. Thank you for your time and have a nice day. John Branthoover: Electrical Design Engineer : Acutronic R D:Phone (412) 968-1051 640 Alpha Drive :Fax(412) 963-0816 Pittsburgh PA 15238 :Email [EMAIL PROTECTED] USA :WEBhttp://www.acutronic.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6.
John, You are not doing anything wrong, it's just Protel. This has been a pet peeve for a long time. Every other system out there will allow this. This is the old problem of having a whole row of 0603 or some other components with a rectangular box around each one of them and Protel demanding that you add and waste additional space between components rather than simply line them up next to each other with a common silkscreen line between them. Protel doesn't understand that this is not really a Design Error, and that it is not a short, and that at worst it should only give you warning (or at least provide a standard means of allowing you to do this without having to resort to kludging something). Options: 1. Make a new component combining the two jumpers, with the silkscreen line seperating them drawn within the component itself. 2. Make a special component with one side of the silkscreen missing so that you can combine it with the other normal component. 3. Use a component that does not have an outline, and place the two of them where you want them, and manually draw your own outlines the way you want them to appear on the silkscreen (Overlay) layer. While this may be the simplest way around the problem, it is a kludge in and of itself simply because it takes extra time and everything gets screwed up if you ever try and move anything involved since the lines are not part of the component. 4. Ignore the DRC Error and overlap the edges of the component so that it does exactly what you want it to do, and then put a note in a text file stored within the database that explains the problem to the next guy who has to work on the project. While I am sure that there will be some out there that will will reply to this post that will have some way to modify some special rule somewhere, my feeling on this is that making special rules for special circumstances is something that should be anathema in EDA Systems simply because the next guy to work on the project will never find it or understand it, and then when someone else (or even you after you forget about the kludge) copies your database at a later date and modifies your file for a similar project he will now end up having a screwed up database with non standard rules that he doesn't even know about and will never find, and you will propagate the special rule for special circumstances kludge down the line ad infinitium, which is shear stupidity. Go with the fourth option above and a note. At least everyone will be able to see it (the DRC Error) and even if they do not understand it, it won't get overlooked and lost in the process. JaMi Smith - Original Message - From: John Branthoover [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Friday, January 17, 2003 9:57 AM Subject: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. Hello All, I have two (2) position jumpers with a rectangular silkscreen drawn around them. I want to place them on my PCB such that one side of the silkscreen overlap. I created a component jumper class and added these two jumpers. In the design rules under Placement, Component Clearance Constraint I set up a rule for the jumper class to have a gap of 0 mil with scope A and B both set to the jumper class. I did this thinking that it would allow me to place the jumper side by side with the silkscreen s on one side overlapping while not affecting other components. I also left the default Component Clearance rule in place - 10 mil gap with scope A and B set to board. When I attempt this I get a violation as soon a s the silkscreen over lap. If I un-check the On-line Component Clearance check box (under Design Rule Check), I stop getting the violations. How ever, if click on the Run DRC button, I still get a violation. Of coarse this also goes away when I un-check the Report Component Clearance check box also under Design Rule Check. What am I doing wrong? Any information that you can give will be greatly appreciated. Thank you for your time and have a nice day. John Branthoover: Electrical Design Engineer : Acutronic R D:Phone (412) 968-1051 640 Alpha Drive :Fax(412) 963-0816 Pittsburgh PA 15238 :Email [EMAIL PROTECTED] USA :WEBhttp://www.acutronic.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
Okay, call me dumb, but I am having a hard time understanding how the DRC even comes into play, since the clearance constraint is, by definition, a constraint on copper layers only. Since the silkscreen is not a copper layer, the clearance constraint shouldn't even be invoked... What am I missing in this equation? aj -Original Message- From: JaMi Smith [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 2:27 PM To: Protel EDA Forum Cc: JaMi Smith Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. John, You are not doing anything wrong, it's just Protel. This has been a pet peeve for a long time. Every other system out there will allow this. This is the old problem of having a whole row of 0603 or some other components with a rectangular box around each one of them and Protel demanding that you add and waste additional space between components rather than simply line them up next to each other with a common silkscreen line between them. Protel doesn't understand that this is not really a Design Error, and that it is not a short, and that at worst it should only give you warning (or at least provide a standard means of allowing you to do this without having to resort to kludging something). Options: 1. Make a new component combining the two jumpers, with the silkscreen line seperating them drawn within the component itself. 2. Make a special component with one side of the silkscreen missing so that you can combine it with the other normal component. 3. Use a component that does not have an outline, and place the two of them where you want them, and manually draw your own outlines the way you want them to appear on the silkscreen (Overlay) layer. While this may be the simplest way around the problem, it is a kludge in and of itself simply because it takes extra time and everything gets screwed up if you ever try and move anything involved since the lines are not part of the component. 4. Ignore the DRC Error and overlap the edges of the component so that it does exactly what you want it to do, and then put a note in a text file stored within the database that explains the problem to the next guy who has to work on the project. While I am sure that there will be some out there that will will reply to this post that will have some way to modify some special rule somewhere, my feeling on this is that making special rules for special circumstances is something that should be anathema in EDA Systems simply because the next guy to work on the project will never find it or understand it, and then when someone else (or even you after you forget about the kludge) copies your database at a later date and modifies your file for a similar project he will now end up having a screwed up database with non standard rules that he doesn't even know about and will never find, and you will propagate the special rule for special circumstances kludge down the line ad infinitium, which is shear stupidity. Go with the fourth option above and a note. At least everyone will be able to see it (the DRC Error) and even if they do not understand it, it won't get overlooked and lost in the process. JaMi Smith - Original Message - From: John Branthoover [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Friday, January 17, 2003 9:57 AM Subject: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. Hello All, I have two (2) position jumpers with a rectangular silkscreen drawn around them. I want to place them on my PCB such that one side of the silkscreen overlap. I created a component jumper class and added these two jumpers. In the design rules under Placement, Component Clearance Constraint I set up a rule for the jumper class to have a gap of 0 mil with scope A and B both set to the jumper class. I did this thinking that it would allow me to place the jumper side by side with the silkscreen s on one side overlapping while not affecting other components. I also left the default Component Clearance rule in place - 10 mil gap with scope A and B set to board. When I attempt this I get a violation as soon a s the silkscreen over lap. If I un-check the On-line Component Clearance check box (under Design Rule Check), I stop getting the violations. How ever, if click on the Run DRC button, I still get a violation. Of coarse this also goes away when I un-check the Report Component Clearance check box also under Design Rule Check. What am I doing wrong? Any information that you can give will be greatly appreciated. Thank you for your time and have a nice day. John Branthoover: Electrical Design Engineer : Acutronic R D:Phone (412) 968-1051 640 Alpha Drive :Fax(412) 963-0816 Pittsburgh PA
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
Well I guess that is also why when you move a Ref Des on a part that is tied to VCC or GND it take a bit of time to keep analyzing VCC under DRC. Never seen a system do that. I can see a need to specifically drc silkscreen to pads etc on the board but not every time you touch a Ref'Des. And yes you can turn off DRC bu tit still seems to do it and actually whay should you have to turn it off just to touch a silkscreen? Bob Wolfe. - Original Message - From: [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Friday, January 17, 2003 3:04 PM Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6 . Okay, call me dumb, but I am having a hard time understanding how the DRC even comes into play, since the clearance constraint is, by definition, a constraint on copper layers only. Since the silkscreen is not a copper layer, the clearance constraint shouldn't even be invoked... What am I missing in this equation? aj -Original Message- From: JaMi Smith [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 2:27 PM To: Protel EDA Forum Cc: JaMi Smith Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. John, You are not doing anything wrong, it's just Protel. This has been a pet peeve for a long time. Every other system out there will allow this. This is the old problem of having a whole row of 0603 or some other components with a rectangular box around each one of them and Protel demanding that you add and waste additional space between components rather than simply line them up next to each other with a common silkscreen line between them. Protel doesn't understand that this is not really a Design Error, and that it is not a short, and that at worst it should only give you warning (or at least provide a standard means of allowing you to do this without having to resort to kludging something). Options: 1. Make a new component combining the two jumpers, with the silkscreen line seperating them drawn within the component itself. 2. Make a special component with one side of the silkscreen missing so that you can combine it with the other normal component. 3. Use a component that does not have an outline, and place the two of them where you want them, and manually draw your own outlines the way you want them to appear on the silkscreen (Overlay) layer. While this may be the simplest way around the problem, it is a kludge in and of itself simply because it takes extra time and everything gets screwed up if you ever try and move anything involved since the lines are not part of the component. 4. Ignore the DRC Error and overlap the edges of the component so that it does exactly what you want it to do, and then put a note in a text file stored within the database that explains the problem to the next guy who has to work on the project. While I am sure that there will be some out there that will will reply to this post that will have some way to modify some special rule somewhere, my feeling on this is that making special rules for special circumstances is something that should be anathema in EDA Systems simply because the next guy to work on the project will never find it or understand it, and then when someone else (or even you after you forget about the kludge) copies your database at a later date and modifies your file for a similar project he will now end up having a screwed up database with non standard rules that he doesn't even know about and will never find, and you will propagate the special rule for special circumstances kludge down the line ad infinitium, which is shear stupidity. Go with the fourth option above and a note. At least everyone will be able to see it (the DRC Error) and even if they do not understand it, it won't get overlooked and lost in the process. JaMi Smith - Original Message - From: John Branthoover [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Friday, January 17, 2003 9:57 AM Subject: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. Hello All, I have two (2) position jumpers with a rectangular silkscreen drawn around them. I want to place them on my PCB such that one side of the silkscreen overlap. I created a component jumper class and added these two jumpers. In the design rules under Placement, Component Clearance Constraint I set up a rule for the jumper class to have a gap of 0 mil with scope A and B both set to the jumper class. I did this thinking that it would allow me to place the jumper side by side with the silkscreen s on one side overlapping while not affecting other components. I also left the default Component Clearance rule in place - 10 mil gap with scope A and B set to board. When I
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
At 03:04 PM 1/17/2003, [EMAIL PROTECTED] wrote: Okay, call me dumb, but I am having a hard time understanding how the DRC even comes into play, since the clearance constraint is, by definition, a constraint on copper layers only. Since the silkscreen is not a copper layer, the clearance constraint shouldn't even be invoked... What am I missing in this equation? The Component Clearance rules are separate from the copper clearance rules. Design Rules/Placement/Component Clearance Constraint. It is an example of where the feature was pretty obviously not run through extensive testing with real designers before being frozen. There were several possible solutions, not at all difficult, I'd think, but they didn't do it. This should have been fixed by SP6 My solution to this problem, since Protel component clearance checking is too defective to use, unless one specially designs footprints (i.e., footprints with the outline retracted sufficiently so that the *outside*, not centerline, of the outline is at minimum clearance -- I haven't done this, but it should work, maybe one would have to retract another mil), I disable the component clearance checking. (uncheck the Enabled box for all clearance rules that can cause problems, i.e., that will generate phony errors.) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
John, adding to Jami's list. 5) Do as I do, turn off the component placement DRC check completely. It just doesn't work in any usable manner. Use your eyes and personal knowledge. The component placement DRC uses any land pattern item, visible, invisible, regardless of layer to determine the maximum extent of the component. It then draws a bounding box around all these items, this constitutes the component boundary for the placement checking. Therefore any designator, comment, text string, etc. gets included with the actual desired component boundary. As you have found setting 0 allows placement down to touching but will still show a violation if items actually touch. I too think that this is a failing of Protel/Altium, a setting of 0 should allow items to touch. It probably should allow overlap as well but I wouldn't push it that far because I don't see that being really useful or a common need. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com -Original Message- From: John Branthoover [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 9:57 AM To: Protel EDA Forum Subject: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. SNIP What am I doing wrong? Any information that you can give will be greatly appreciated. Thank you for your time and have a nice day. John Branthoover: Electrical Design Engineer : Acutronic R D:Phone (412) 968-1051 640 Alpha Drive :Fax(412) 963-0816 Pittsburgh PA 15238 :Email [EMAIL PROTECTED] USA :WEBhttp://www.acutronic.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
Andrew, my understanding is that he is talking of the component placement DRC check. It checks the area bounding all portions/layers of the land pattern to the bounding area of the next land pattern. It isn't a copper check but a component to component clearance check. Like myself or a number of others, you probably have it turned off since early in the P99 days. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 12:05 PM To: Protel EDA Forum Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6 . Okay, call me dumb, but I am having a hard time understanding how the DRC even comes into play, since the clearance constraint is, by definition, a constraint on copper layers only. Since the silkscreen is not a copper layer, the clearance constraint shouldn't even be invoked... What am I missing in this equation? aj * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
Frankly, I don't even understand concerns about silkscreen and pads. The silkscreen simply will not be printed over the solder area, since the pad-mask prevents adherence of the ink to these areas. Admittedly, one might lose bits of a character or outline this way, but the person responsible for laying out a board should IMO be doing a visual check after layout anyway, and this should catch any glaring problems, ie, entire designators sitting atop ajoining pad(s)... Okay, I admit I can see a reason for DRC'ing ref-designators vs. pad holes, anwyay, at least for dense designs... aj -Original Message- From: Robert M. Wolfe [mailto:[EMAIL PROTECTED]] Well I guess that is also why when you move a Ref Des on a part that is tied to VCC or GND it take a bit of time to keep analyzing VCC under DRC. Never seen a system do that. I can see a need to specifically drc silkscreen to pads etc on the board but not every time you touch a Ref'Des. And yes you can turn off DRC bu tit still seems to do it and actually whay should you have to turn it off just to touch a silkscreen? From: [EMAIL PROTECTED] Okay, call me dumb, but I am having a hard time understanding how the DRC even comes into play, since the clearance constraint is, by definition, a constraint on copper layers only. Since the silkscreen is not a copper layer, the clearance constraint shouldn't even be invoked... What am I missing in this equation? From: JaMi Smith [mailto:[EMAIL PROTECTED]] John, You are not doing anything wrong, it's just Protel. From: John Branthoover [EMAIL PROTECTED] I have two (2) position jumpers with a rectangular silkscreen drawn around them. I want to place them on my PCB such that one side of the silkscreen overlap When I attempt this I get a violation as soon as the silkscreen over lap What am I doing wrong? * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
At 04:30 PM 1/17/2003, [EMAIL PROTECTED] wrote: Frankly, I don't even understand concerns about silkscreen and pads. The silkscreen simply will not be printed over the solder area, since the pad-mask prevents adherence of the ink to these areas. The component clearance rule is not about the silkscreen, it merely uses the silkscreen as an indicator of component extents. The idea is great, the implementation fell short. We have talked about dedicating a mech layer to a true component outline, the clearance rule would then use that layer, looking for clearance between the outlines. There are plenty of details to be worked out, such as tolerances -- part outlines would be drawn at MMC, not at nominal, and the clearance would either be centerline or the outline would compensate so that the outer edge of the outline trace was the maximum possible condition Then the component clearance rule would actually refer to true component clearance (i.e. minimum clearance) instead of to some nominal value or worse. The clearance function should look for distance between outline tracks on the component outline layer, not to the extents box, which does not work with some kinds of component shapes. The rule should also allow negative clearance, i.e., overlap (which, had it been done, would have allowed the present system to function well enough to use.) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 . Thanks....!
Thanks again everyone for the response. Again my lack of experience is showing. Oh well, I have to learn some how. I hope that every body has a nice weekend. -Original Message- From: Brad Velander [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 4:13 PM To: 'Protel EDA Forum' Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6 . Andrew, my understanding is that he is talking of the component placement DRC check. It checks the area bounding all portions/layers of the land pattern to the bounding area of the next land pattern. It isn't a copper check but a component to component clearance check. Like myself or a number of others, you probably have it turned off since early in the P99 days. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 12:05 PM To: Protel EDA Forum Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6 . Okay, call me dumb, but I am having a hard time understanding how the DRC even comes into play, since the clearance constraint is, by definition, a constraint on copper layers only. Since the silkscreen is not a copper layer, the clearance constraint shouldn't even be invoked... What am I missing in this equation? aj * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
I agree that turning off component clearance checking completely is a solution of sorts, but I myself am not comfortable doing that, since I am not quite perfect yet (almost, but not yet), and I would rather have to look at an error on the screen due to a bogus problem with Protel 99 times out of 100 (is that where the 99 came from), as opposed to look at an error in the built hardware just once because I blew it and it wasn't caught because I turned off the clearance checking. JaMi - Original Message - From: Brad Velander [EMAIL PROTECTED] To: 'Protel EDA Forum' [EMAIL PROTECTED] Sent: Friday, January 17, 2003 11:48 AM Subject: Re: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6 . John, adding to Jami's list. 5) Do as I do, turn off the component placement DRC check completely. It just doesn't work in any usable manner. Use your eyes and personal knowledge. The component placement DRC uses any land pattern item, visible, invisible, regardless of layer to determine the maximum extent of the component. It then draws a bounding box around all these items, this constitutes the component boundary for the placement checking. Therefore any designator, comment, text string, etc. gets included with the actual desired component boundary. As you have found setting 0 allows placement down to touching but will still show a violation if items actually touch. I too think that this is a failing of Protel/Altium, a setting of 0 should allow items to touch. It probably should allow overlap as well but I wouldn't push it that far because I don't see that being really useful or a common need. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com -Original Message- From: John Branthoover [mailto:[EMAIL PROTECTED]] Sent: Friday, January 17, 2003 9:57 AM To: Protel EDA Forum Subject: [PEDA] A Question About PCB Design Rules. Protel 99SE SP6. SNIP What am I doing wrong? Any information that you can give will be greatly appreciated. Thank you for your time and have a nice day. John Branthoover: Electrical Design Engineer : Acutronic R D:Phone (412) 968-1051 640 Alpha Drive :Fax(412) 963-0816 Pittsburgh PA 15238 :Email [EMAIL PROTECTED] USA :WEBhttp://www.acutronic.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] A Question About PCB Design Rules..... Protel 99SE SP6 .
Abd ul-Rahman Isn't this just really saying the silkscreen IS the defining factor IMHO the silkscreen layer should never have been used as an indicator or ultimately the real extents of a part. There really needs to be a user defined layer that will be used at the extents of a part to check part clearance. And that layer does not necesarily have to be an assembly layer. I have seen systems that define both actual part and real world clearances required for assembly/test/rework etc., and control over which rule pending level of technology required for design. And line widths really should have nothing to do with it when you are defining a clearance just center as if it were a zero width line. Only silkscreen itself should be considered for thickness itself with respect to all other features. But part clearance should be to a dimension MMC, etc not ever dealing with the thickness of a line defining it. Bob Wolfe The component clearance rule is not about the silkscreen, it merely uses the silkscreen as an indicator of component extents. The idea is great, the implementation fell short. We have talked about dedicating a mech layer to a true component outline, the clearance rule would then use that layer, looking for clearance between the outlines. There are plenty of details to be worked out, such as tolerances -- part outlines would be drawn at MMC, not at nominal, and the clearance would either be centerline or the outline would compensate so that the outer edge of the outline trace was the maximum possible condition * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
