Fiducial corrections lost in Y? direction when board height is altered

[Greg Toman]

This is a very significant problem. Anyone using openpnp should be aware of this problem.

If you update the height of your board after doing a fiducial check, the corrections created by the fiducial check in the "Y" direction will be lost! (Note: The board I am placing is rotated -90 degrees in my board holder, so I can't be certain if Y is affected, or X is affected due to this rotation).

The problem was found because I would slightly adjust the height of the board during placement. The board is large, and for some unknown reason, sometimes the parts were placed firmly into the paste, and occasionally they would not be. (Possibly due to slight warpage of the board.)

No warning is issued. Placements following the altering the of z height of your board will be inaccurate.  This is a major problem!

Related to this, I have suggested in the past Openpnp should warn you if you start a job and have not performed a fiducial check. This warning could have a "do not warn me again" option, but this one mistake can ruin a pc board.  

Sorry to complain. I think Openpnp is great, but anything that unknowingly alters the accuracy of placements is a big issue!

Thanks 

Greg

[tonyl...@gmail.com]

Currently, if you alter any of the board's coordinates (x, y, z, or rotation) the previous fiducial check data (if any) is invalidated. We probably could allow changes to the Z component that don't invalidate the fiducial check data.  You are aware that if you have the board's Check Fids? checkbox ticked on the Job tab, a new fiducial check will be performed at the start of each job so that should alleviate most of your issue.