Eric H. Johnson wrote: > The run-away problem seems to be licked, at least for relatively slow speeds. > I am, however, still getting following errors at higher velocities. These > start to occur at about 3IPS. The motors should max out at about 12 IPS. Max > step rate on the motors should be 20 RPS * 200 steps per revolution * 16 > micro-steps per step, or 64000 steps per second. At 3 IPS, it should be about > 16000 steps per second.
Yay! Thanks for the debugging work, Eric! Is this with the latest stepgen.c that I posted earlier today? > I have base period set to 25000 nsec, and servo period set to 200000 nsec. > > I assume the following error results from position-fb getting too far behind > position-cmd, but I do not know what needs to be done to resolve this problem. What are you doing in the base thread? It shouldnt be needed for this setup, as I understand it. I'm not sure how to approach this following problem. Matt Shaver reported a similar problem... I think Steve found a bug in Matt's stepgen config, but I'm not sure if fixing that bug fixed his following error. The wiki FollowingError page, <http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Following_Error>, suggests that following errors with steppers might be because ferror or min_ferror are too low, or maxaccel or maxvel might be too high. (BTW, that page has a broken picture on it.) How does emc2 decide that a following error is happening? Is it true that when emc2 interprets g-code, it makes a long array of points (in whatever axis-space the machine operates) and feeds each set of coordinates to the position-cmd pins on the controllers for the various axes? > Secondly, now that I am back to it, the PWM does not seem to be changing. It > is either off, or what seems to be close to full on. My meter reads either 0V > or 3.16V. I did find that a mirror must have gotten bumped, resulting in > apparently low output from the laser. Following a beam alignment, laser power > does look to be close to full on. > > Any ideas on how to troubleshoot this is appreciated. I think measuring a PWM signal with a voltmeter isnt reliable; it depends on how fast the meter is. Isn't there some simple RC circuit that can be placed between the PWM pin and ground to make a duty-cycle-controller voltage that can be reliably measured with a DMM? I really dont know but I think I read something like that... -- Sebastian Kuzminsky Theo: "Julian? I haven't seen you in twenty years. You look good. The picture the police have of you doesn't do you justice." Julian: "What do the police know about justice?" ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
