WHAT THE F*CK??
I went refining a more precise test- now you just do at most 8 decimation steps and it will always get you an exact number- to the microsecond- with no guesswork.
THIS IS AMAZING!!!
OK, at first I was really happy I got an exact number for the TCON/TCOFF. Then I went experimenting and every single new thing I thought to test just blew my mind!!!
First off, high-speed and high-res raster image quality went through the roof.
My common SG7110 scan head is rated for 7000mm/s rapids. But vendor info on Aliexpress only rates it for 5000mm/s marking.
Well, I just scanned 1.5mm tall SHX fonts at 7000 mm/s. It is flawless under high magnification, it looks nothing like I’ve ever seen at this level. Everything is straight, the corners meet up dead-on, there’s very little “overburn”, and no “matchsticking”
I dove down that rabbit hole and I see the problem. You MUST have TCON/TCOFF set precisely- to the microsecond- or all subsequent cals will be “off” and it creates a confounding problem with the other parameters.
The ramifications here are pretty profound. We haven’t been calibrating these correctly- no one, apparently. With the right test, getting precise cal is easy.
It appears that the only reason galvo heads aren’t recommended to be used at anywhere near their max speed is actually due to lack of accurate calibration routines.
The TCON/TCOFF does NOT change with speed or q-pulse. You cal once at max speed and it will be valid at lower speeds. The reason people saw the cal needed to change for higher speeds was that it was always “off” by quite a bit but the consequences just aren’t as significant at lower speeds
Now I understand more about the galvo’s motion control- Overscan now seems unnecessary, in fact I suspect LB may not even be able to tell it to do that as that level of handling comes from hardware