Jan de Kruyf wrote: > Do you get those errors with servos Gene? or with steppers! > > I am interested, since Jon was praising that board so much. > > >> >> But I am encountering following errors after the motor has reached speed >> and moved a good distance at that speed, but don't know what to adjust that >> affects that. >> >> This is caused by requesting a greater pulse rate than the base thread can put out. One possible cause is if the pulse width setting is made too large. You want this set correctly for the motor drive, but not any larger. Then, figure out at what feedrate the error shows up. Say that is 50 IPM. And, for example, say it takes 30,000 steps to move one inch. (50 IPM / 60) X 30,000 = 25000 steps/second. Now, assuming you are using the best step generator scheme which times the pulse width, if your base thread was greater than 40 us (40,000 ns) then you can't go that fast. Or, if you set the step pulse width to 20 us, then you can't go that fast. (50% hi, 50% low, of 20us each adds up to 40 us.
So, just do the calc, and see what time is 1/step pulse rate, and then compare to your base thread time. Your base thread really needs to be MUCH higher than the fastest step pulse rate, due to the granularity. If the machine were running at a speed where every other base thread cycle produced a step pulse, then the next higher speed would require a step pulse EVERY base thread cycle, which is a 100% speed jump. LinuxCNC can certainly send pulses at that rate, but that is too large a speed jump for the motor to follow. Jon ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
