Hi Sam, > From: Sam Sokolik [mailto:samco...@gmail.com] > Is this stepper torque? The peak torque is only at 0 rpm and drops off > substantially as you increase rpm. You would need to look a the torque > curve of the stepper and decide what top rpm you are looking for and > calculate accordingly..
The discussion started with what sort of values and driver to install for a specific Servo. Jon became involved because he sells servo drivers. And then he made a mistake with scaling units and then I made a mistake with scaling units and it's really clear a tool to figure this out would be handy. At least as a starting point and then tweaking the actual values still might be required. For example someone might not take apart their entire XY table assembly to weigh it to figure out how big a servo or stepper they need. Mostly they will look at what's out there, listen to feedback and then decide. My issue is the math still doesn't make sense. If I try 1700in/Sec^2 the servo faults instantly. MAX_ACCELERATION that works is about 40 in/sec^2 without faults. And Actually I run 20 for MAX_ACCELERATION and STEPGEN_MAXACCEL at 40 because I use backlash and it's supposed to be 100% larger. So with Jon being the Servo designer I thought perhaps he could answer why there's such a large disparity. Or is there still a math conversion problem here? John > > > Ho Jon, > > > > I've changed the subject line to be more relevant and corrected the > > gravity value. > > > > Now we have 1703 In/Sec^2 for maximum possible acceleration given the load > > and torque ratings. > > > > On my system in imperial units I have 2.5 inches/second and I randomly > > picked the accel as 3x that. Does that mean I could set MAX_ACCEL to say > > 1700 and get away with that or is that number abnormally high? I know I > > can try it but I'd like to know if the math is accurate. > > > > MAX_VELOCITY = 2.5 > > MAX_ACCELERATION = 7.5 > > What I'm trying to do with this tool is to take out some of the guesswork > > or the accidental divide instead of multiply. > > > > And second question. If someone is using metric units for their system > > what units are used to describe MAX_VELOCITY and ACCEL? > > Is it mm/minute? Or mm/second? Or meters/second? Is the weight > > specified in grams or kg? > > > > I want to be able to make the checkbox convert the imperial < = > metric > > correctly. > > > > > > > > Thanks > > John Dammeyer > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
