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initial automatic component placement grid is wrong/how to change it

autodeskguest

I'm using Eagle Pro 6.6.

 

I noticed a behaviour that has me very frustrated and I can't find a way

to fix it.

 

If I create a Schematic with say 64 LED's (SMD devices to created with a

grid on 0.1mm in the library)

 

And wire them up appropriately in the schematic.

 

then switch to the PCB view, the 64 LED's are automatically placed on

the board outside of the default PCB area, but they are placed in a n

array  pattern that i have no control over, and that seems to be

slightly off when I then set the PB grid to 0.1mm for placement...

 

from row to row of LED's they are slightly misaligned when i pick them

up to place them they don't line up correctly with LED's that were

dropped in the array on the line above, or to the right...

 

So I am having a devil of a job laying out my final array or LED's

according to an exact alignment as the components are off some fraction

of my grid that I can't adjust for (even with the fine grid set very

fine), and anyway that is now extremely time consuming (imaging 1000

LED's that all need to be manually aligned rather than snapping to an

exact grid.

 

Is there a fix for this initial automatic grid when initially creating a

PCB to work on ?

 

Any help or ULP's to fix this would be appreciated...

 

I even took a look at editing the .brd XML file and while is looks

possible it is too daunting of a task and possibly more manual and

probably error prone.

 

Parents

  • peter wrote on Sat, 30 August 2014 18:54

    Is there a fix for this initial automatic grid when initially creating

    a PCB to work on ?

     

    By mentioning "fix", you imply there is anything wrong with how it works

    now.  There isn't.  There is no reason to care where exactly unplaced part

    are initially put off-board, since they are, well, unplaced.

     

    Normally you wouldn't even have the sea of unplaced parts in view when

    doing placement.  All that matters is that they are out there somewhere.

    As you walk thru the schematic (I print it out, then cross off parts as I

    place them) to place parts on the board, you enter the part name and it

    shows up at the cursor.  Wherever it was previous to that is completely

    irrelevant.

     

    However, when you have a regular array of parts to place, you wouldn't do

    this manually anyway.  That would be too slow, tedius, and unreliable.

    Write a program that generates the script to place the array of parts, then

    run the script.  The original positions of all the placed parts is

    irrelevant.  If there is a error in the script or you want to change

    something, you regenerate and rerun the script.  The parts will show up in

    their new positions, this time even though they were previously placed on

    the board.  Again, the previous positions of the parts doesn't matter.

     

    There is no problem here, so nothing to fix.

    --

    Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

     

  • in reply to autodeskguest

    On 08/31/2014 04:48 AM, Olin Lathrop wrote:

    peter wrote on Sat, 30 August 2014 18:54

    Is there a fix for this initial automatic grid when initially creating

    a PCB to work on ?

     

    By mentioning "fix", you imply there is anything wrong with how it works

    now.  There isn't.  There is no reason to care where exactly unplaced part

    are initially put off-board, since they are, well, unplaced.

     

    yes and no. yes they are 'unplaced' but they are unplaced according to a

    grid that is derived from the defaults set up in the eagle.scr file.

     

    once they have been 'unplaced' they are tied to a position relative to

    the grid (initially they are on a 0.1" grid), but if I change to a 1mm

    grid they now obtain a new relative position according to their current

    position off the 1mm grid, and when moved they will maintain that offset

    from the 1mm grid, getting them back onto the 1mm grid is what I'm

    struggling with.

     

     

     

     

    Normally you wouldn't even have the sea of unplaced parts in view when

    doing placement.  All that matters is that they are out there somewhere.

    As you walk thru the schematic (I print it out, then cross off parts as I

    place them) to place parts on the board, you enter the part name and it

    shows up at the cursor.  Wherever it was previous to that is completely

    irrelevant.

     

    I have not delved into writing ULPs yet... one day when i have time.

     

    However, when you have a regular array of parts to place, you wouldn't do

    this manually anyway.  That would be too slow, tedius, and unreliable.

    Write a program that generates the script to place the array of parts, then

    run the script.  The original positions of all the placed parts is

    irrelevant.  If there is a error in the script or you want to change

    something, you regenerate and rerun the script.  The parts will show up in

    their new positions, this time even though they were previously placed on

    the board.  Again, the previous positions of the parts doesn't matter.

     

    There is no problem here, so nothing to fix.

     

     

     

     

     

  • in reply to autodeskguest

    peter wrote on Mon, 01 September 2014 05:05

     

    Normally you wouldn't even have the sea of unplaced parts in view

    when

    doing placement.  All that matters is that they are out there

    somewhere.

    As you walk thru the schematic (I print it out, then cross off

    parts as I

    place them) to place parts on the board, you enter the part name

    and it

    shows up at the cursor.  Wherever it was previous to that is

    completely

    irrelevant.

     

    I have not delved into writing ULPs yet... one day when i have time.

     

     

    Huh?  What does anything I mentioned there have to do with ULPs?  Read what

    I wrote.  This is just using Eagle commands normally.

     

     

    --

    Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

     

Reply
  • in reply to autodeskguest

    peter wrote on Mon, 01 September 2014 05:05

     

    Normally you wouldn't even have the sea of unplaced parts in view

    when

    doing placement.  All that matters is that they are out there

    somewhere.

    As you walk thru the schematic (I print it out, then cross off

    parts as I

    place them) to place parts on the board, you enter the part name

    and it

    shows up at the cursor.  Wherever it was previous to that is

    completely

    irrelevant.

     

    I have not delved into writing ULPs yet... one day when i have time.

     

     

    Huh?  What does anything I mentioned there have to do with ULPs?  Read what

    I wrote.  This is just using Eagle commands normally.

     

     

    --

    Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

     

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