On Mon, 2008-09-15 at 20:25 -0600, Sebastian Kuzminsky wrote: > Hooray! My sentiments exactly!
> Hm, not sure about this one. stepgen.position-cmd is the target > position: where it wants to be at the end of the current move; > stepgen.position-fb is the current position. While in transit the two > will differ, while at rest the will be the same. > > I don't know enough about the motion controller in emc2 to say why this > is happening. I'll have to study up on this. One peculiarity of EMC1 was that it treated stepper motors (position commanded) as if they were servos (velocity commanded). The blame for this can be placed squarely at my own feet :) . I don't know what's happened in the code since then, or if this behavior has been inherited by EMC2. I may have to halscope a bunch of things to see what the problem is. > What's your stepgen.maxaccel and stepgen.maxvel? They both default to > 1.0, which is probably pretty low. Oh wait I saw in your INI file below > that you upped them to maxvel=10 and maxaccel=100. My thought was to allow the fpga stepgen all the latitude it needed to follow the commanded position and acceleration. > Huh? In TRUNK the hm2 stepgen uses u32 params for the waveform timing > and the manpage reflects this; in 2.2 the hm2 stepgen uses floats and > the manpage reflects this. Is you MANPATH taking you to an old install? Oops, sorry, you're right. My bad... > Wow, 40K steps/inch?! Here's the system details: Screw Pitch = 4 turns/inch Motor Steps = 200/rev Microsteps= 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 200 (switch selectable) Drive Maximum Step Rate = 200kHz My goals are: 1. Fastest possible rapid moves. 2. Quiet operation to be achieved by ultrasonic step rates. My first configuration was 200uSteps/Step giving: 200 Motor Steps * 200 uSteps * 4 Screw Turns/Inch = 80000 Steps per Inch (200000 Hz Max Step Rate / 80000 Steps per Inch) * 60 Seconds per Minute = 150 Inches per Minute Maximum Feed Rate This was _very_ smooth and quiet (nearly servo level quiet), but the best I could do was about 100-120 IPM before following errors killed my joy ;) . Also, I know that with the motors, drives, power supply, mechanics, etc. of this machine, the maximum rapid rate should be 200-300 IPM. I then dropped down to 100uSteps/Step which was still extremely smooth in operation, but I was dieing at about 220IPM on following errors :'( . To me, the true promise and ultimate value of the Mesa hardware is high frequency, high granularity step rates with minimum processing load on the PC. I think if we can get it to play nicely with EMC, the results will be impressive! > Your HELP_FILE disagrees with your DISPLAY (but maybe that's ok, I dont > know). I think that all the GUIs use the tkemc help file. Maybe axis has it's own(?). > Shouldnt your HAL file use variables from the INI file? (I've never > written an emc2 ini file so I dont know.) Yep, but I started out loading this HAL file from halcmd. Today I'm going to fix it up the right way! Thanks, Matt ------------------------------------------------------------------------- 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-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
