Playing with mach3 - You can set the number of lines look-ahead. 20 this was the default - The spiral program peaks at 440ipm (which seems the maximum) 2 - this seems to close the current linuxcnc implementation - peaks at about 110ipm 9 - for the spiral programs line segment lengths - seems to be the minimum read ahead to peak at the 440ipm
(for reference (whatever it is worth)) sam On 9/16/2013 11:49 AM, Jon Elson wrote: > sam sokolik wrote: >> I think a larger read-ahead is the priority. >> > Yes, there are only two ways to deal with this. The safe way requires the > interpreter to sanitize the tool path before handing it to the > trajectory planner, > so there will be no surprises while moving at high velocity. > > The other way is to assume the CAM system never generates code the > machine can't follow, and if it occurs, then you have a massive velocity > discontinuity. This might make some people quite happy, as they could > do high speed contouring that you can't do now with LinuxCNC. > But, of course, it is a bit dangerous, the "trust me, I know what I'm > doing" mode of operation. > > The problem with the "larger read-ahead" is that there is no best > choice for how much read-ahead you need, and doing it in real > time gets pretty complicated. It is conceivable that you could need > 1000 blocks of read ahead in some contouring programs, and I > don't think you can have the TP do this for every line and arc > segment. My naive scheme was to have a big buffer of the > trajectory moves, and when you hit a part that required slowing > down, you could then work backwards to figure out when you > needed to begin the slowing down. There would be a velocity > for each move, and this working backwards scheme would edit > those velocities down to accommodate the need for acceleration > in the future. Not sure if this makes sense, but that was what > seemed to be the mechanism that made the problem tractable > to me. > > Jon > > ------------------------------------------------------------------------------ > LIMITED TIME SALE - Full Year of Microsoft Training For Just $49.99! > 1,500+ hours of tutorials including VisualStudio 2012, Windows 8, SharePoint > 2013, SQL 2012, MVC 4, more. BEST VALUE: New Multi-Library Power Pack includes > Mobile, Cloud, Java, and UX Design. Lowest price ever! Ends 9/20/13. > http://pubads.g.doubleclick.net/gampad/clk?id=58041151&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > > ------------------------------------------------------------------------------ LIMITED TIME SALE - Full Year of Microsoft Training For Just $49.99! 1,500+ hours of tutorials including VisualStudio 2012, Windows 8, SharePoint 2013, SQL 2012, MVC 4, more. BEST VALUE: New Multi-Library Power Pack includes Mobile, Cloud, Java, and UX Design. Lowest price ever! Ends 9/20/13. http://pubads.g.doubleclick.net/gampad/clk?id=58041151&iu=/4140/ostg.clktrk _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
