Fengli Zhang wrote: > Hi,all > Ham trying to configure a cnc system for a stepper-based 3 axes mill > machine > using emc2. I know that the sample configure about stepper is an open-loop > one. And I intend to modify it to a closed- loop one with position and > velocity feedback. So what should I add to the sample configure ? Just > adding 3 encoders is ok ? How to add(How to modify the .hal files)? > If you have an idea ,please let me know ,thank u ! > > Yours > Fengli Zhang
"Steppers" and "closed loop" are not usually used together. In a normal servo loop (PID), if the actual position starts to fall behind, the PID loop increases the output to make it catch up. But if a stepper is starting to fall behind (too much load torque), increasing the step rate will just make it worse, resulting in lost steps. It is theoretically possible to use the lag between commanded and actual stepper position to drive the adaptive feed input and slow the whole machine down to prevent the steppers from losing steps, but this would be very much an experimental thing. More of a research project than a machine design. If you wish to do such things, you should read the HAL manual and become comfortable customizing the HAL. Regards, John Kasunich ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
