This thread has some good information about this https://sourceforge.net/p/emc/mailman/message/34363029/
For interest sake I set my mill up to turn 1 RPS with my 60 tooth non-symmetrical encoder (4mm slots, 2.5mm teeth) and then ran the power tapping G-Code to see what the knee Z axis would do. What I found is that it moved in short spurts. Putting my finger on the knee and against the column it still appeared to move rather slowly with less of a jerk. All this makes sense of course. My servo period is 1000000 nanoseconds or 1 ms. At 1 RPM that's one tooth every second or 4 encoder edges per second meaning one edge every 250mS. That's 250 servo periods. What I think I'm seeing is that every 250 servo periods the system detects the encoder edge and knows it's moved 1/240th of the 20 TPI thread. (0.000208333") So it tells the Z axis to move that same distance and I suspect the velocity setting of 0.0002083333/250mS. Does that make sense? Is there a way to log each Z axis speed/distance command so I can see what it's doing? Or have I misunderstood how the power tapping synchronized motion is done. Thanks John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
