> The basic question I guess is would EMC be able to provice the same tool > path quality as the (lower end) Siemens or Heidenhain controllers?
You should run EMC in simulator mode, and use halscope or halstreamer to record all the joint positions to disk. Then you can analyze this data later for correctness/smoothness. It is fairly easy to "choke" the EMC interpreter/traj-planner with G-code which consists of many many short G01-segments. It could be argued that these should be filtered to longer lines, arcs, biarcs or NURBS G-code, but if you have a CAM-program that only outputs these short G01-segments this could become a problem. Even with a hobby mill this is an issue. We have 5m/min rapids on our machine and when programming a contouring operation at say for example 2m/min feedrate, if the CAM-program outputs lots and lots of short G01-segments the EMC interpreter/traj-planner will not handle it well and the actual feedrate may be 1m/min or even lower. You should be able to test for this in simulator mode (see above). Improving the trajectory-planner is not an easy task. I think the consensus reached last time we were discussing this is that it is a very hard task indeed _unless_ some restrictions are added. For example restricting traj-planner to only 3-axis trivkins and/or restricting feed-override to 0-100% (not >100%). Also I think there is a restriction of one G-code block (or canon-command) per servo thread cycle. If you run a normal servo-thread at 1ms that means 1000-lines of G-code per second (in theory). If your CAM-program outputs more than this you will get the slowed down feedrate I mentioned above. As mentioned by other posters this is a problem you rarely encounter with hobby-grade machines because it only occurs with "bad" CAM-code which consists of the many many small G01 segments and with high-speed machinery where you want to cut at 5m/min or 10m/min (or more!). When you have this kind of cash invested in the machine, the tooling, and are under time-pressure to have to run your machine at 10m/min then suddenly I think investing another 10k or 20k in a pro controller is not a problem... (contrast to sitting down, learning all the innards of emc2, learning trajectory-planning math/geometry, and attempting to write a high-speed traj-planner for EMC2) Anders ------------------------------------------------------------------------------ This SF.net Dev2Dev email is sponsored by: Show off your parallel programming skills. Enter the Intel(R) Threading Challenge 2010. http://p.sf.net/sfu/intel-thread-sfd _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
