Software forcing POS values to Negative

[jgaro]

Hi all, I'm having an issue where the Liteplacer SW is (seemingly arbritarily) changing values in my POS file from positive to negative during an upload. Here's an example:

Code: Select all

# Ref     Val                 Package                                    PosX       PosY       Rot  Side
FID1      RESET               SW_SPST_FSMSM                          149.7840     5.9940   00.0000  bottom
FID2      RESET               SW_SPST_FSMSM                          149.7840    99.1108   90.0000  bottom
FID3      RESET               SW_SPST_FSMSM                           18.1610    78.0034   90.0000  bottom
R2        10k                 R_0805_HandSoldering                    56.7500   -73.0000   90.0000  bottom
R9        10k                 R_0805_HandSoldering                    36.7500   -26.5000   90.0000  bottom
R10       10k                 R_0805_HandSoldering                    34.7500   -25.0000   90.0000  bottom
R12       10k                 R_0805_HandSoldering                    23.7500   -19.5000   90.0000  bottom
R13       10k                 R_0805_HandSoldering                    40.5000   -51.5000   90.0000  bottom
R14       10k                 R_0805_HandSoldering                    36.2500   -59.5000  270.0000  bottom
R31       10k                 R_0805_HandSoldering                    77.7500   -33.7500    0.0000  bottom
R33       10k                 R_0805_HandSoldering                    88.7500   -34.0000  180.0000  bottom
R37       10k                 R_0805_HandSoldering                    22.7500   -72.0000  180.0000  bottom
R38       10k                 R_0805_HandSoldering                    22.7500   -74.0000  180.0000  bottom
R57       10k                 R_0805_HandSoldering                    38.5000   -51.5000   90.0000  bottom
R60       10k                 R_0805_HandSoldering                    38.2500   -47.5000    0.0000  bottom
## End

(these are all either left or right aligned in the file)

When I import, all of the X values change to negative. Any ideas?

[JuKu]

That is how the software handles bottom side of a board. Please see http://www.liteplacer.com/double-sided-boards/.

[jgaro]

For this file, I get an error when trying to load without selecting the Bottom check box. It is indeed a bottom file, but do I then need to re-zero from the top? When I try to move to a location with the negative value, I get an error since it's outside the bounds of the machine.

[JuKu]

If a file does not load correctly, I'd like to get a copy, so I can fix it. Assuming that the file loads correctly but the results are not usable: It looks like your software produces the bottom position data differently than the software expects, and you might need to play with the board offset values and if bottom checkbox needs to be set or not.

This is how LitePlacer thinks the data is: The coordinates in the pick and place file are as you see them on your screen, for both top and bottom side parts. Origin is at bottom left. For example, you have a board 100mm wide, and there is a component far right, 90mm from left. The X coordinate for this part is 90.00, regardless if it is a top or bottom side part. When placing the bottom side, the board is flipped left to right. The origin goes 100mm to right. Y coordinates are not affected. To find parts, you need to tell the software where the origin is now. So, you but 100mm to the board offset X. Also you check the bottom box when loading the data. This tells the software to invert X coordinates. So, the origin is now 100mm from the nominal PCB zero. The above part is still 90mm from the origin, but to the left. The software finds it by taking first the 100mm offset, then adding it the X coordinate, now -90mm. The result is 10mm, which is where the part is.

Your software clearly has a different idea, as there are negative Y values. Maybe the origin is somewhere else than low left? Or, it may be that the idea here is that the board is flipped front to back, so Y coordinates change, X's stay the same, and the bottom position data is produced with coordinates already inverted for you.

You might be able to use the data by not checking the bottom box and setting the board offset Y. If my software and your CAD are indeed incompatible, I'm willing to add the support for that. (Which CAD is this, btw?) For this, I will need a description of how the data is supposed to be interpreted, and maybe some samples. I can talk to the CAD program technical support people also. (I have done this a couple of times already, and software companies are very helpful to get their package supported, although sometimes a bit slow).