[my comments are embedded] On 12/24/2010 2:38 PM, cogoman wrote: > I looked on the Wiki, and believe I could provide something that > would be useful. I could include more information to give a more > complete treatment of the time limiting factors of using stepper > motors. I have a few questions to try to make it more informative, and > since I've never posted to the Wiki I could use some advice. > I'm no Wiki expert but I think you can divine a lot by finding pages on the existing Wiki you want to emulate and examining their markup in editing mode. Also, see the extensive info on this particular Wiki engine at http://www.usemod.com/cgi-bin/wiki.pl > 1: Can I compose this offline using Open Office Writer, and transfer the > final form to the Wiki? Hmmm. I've never tried. When you log in to the Wiki a new "upload" link appears at the top of each page (in addition to the new "edit text of this page" link at the bottom) so I assume one can upload a file of formatted page(s) and then create Wiki links to it from existing pages. Perhaps one of the core wiki maintainers can comment. It would be a bore to have to cut-and-paste many pages between a local editor and the Wiki editor. > 2: Some tables would be helpful. How can I include tables in the Wiki? See http://www.usemod.com/cgi-bin/wiki.pl?TextFormattingRules/WikiTables or just make the table into an image and goto 3. > 3: I could use to include one or two plots from Switcher Cad (many > thanks to the folks at LT). Can I include them as .jpg or .png? See http://www.usemod.com/cgi-bin/wiki.pl?TextFormattingRules#Images for the linkage rules. I've never done it but again I assume one can upload the image files first and then create Wiki links to them in the edited page. > 4: Can you help me with the outline of what to put in there? I apologize for not responding earlier. Life has dealt me some harsh real-world distractions (not, thankfully, involving an over- or under-abundance of water!).
First, thanks for taking the time to generate this outline. I suggested you contribute an ounce and in response you're offering a pound! I haven't had time to think about the subject carefully so I'm not yet prepared to comment in detail. I am warmed by your use of words like "useful" and "more informative" :-) As a general observation, and speaking only for myself, I would expect the EMC2 wiki to emphasize practical aspects of technology as it applies to configuring, using, or troubleshooting EMC2 and simply reference other, more expository accounts, such as the nearly legendary Jones work. Taking your first topic, for example, I'd want the discussion to help me select EMC2 parameters for an existing stepper motor and driver in light of these limitations. Should I decide motor and/or driver is unsuitable, I'd look to this discussion to help guide my selection of more suitable ones. One of the things I really liked about your response to Catherine was your use of real-world numbers. Again, if good material already exists on the web, let's just link to it along with an explanation of why it's worth reading :-) I especially like your thoughts about how all this affects machining. That's what we're here for! > Perhaps it could be called "What Limits a Stepper Motor's Speed in EMC2" > 1: How inductance/voltage/current limits the max stepper motor speed > and how torque drops as speed increases. > 2: How the step/direction interface vs quadrature A/B interface affects > performance along with how discrete speed changes as you approach max > step rate can hurt performance. > 3: How resonances can reduce the maximum speed. > 4: How micro-stepping reduces torque from full step torque. > > Perhaps I could include a little discussion on how an axis getting > behind during cutting might not affect the quality of the part (when the > tool slows to take a corner, the axis can catch up). > How most machining is done at low speeds where torque in a stepper > system is good. > > Any suggestions of how to tweak this outline will be helpful. Thanks! > <remainder deleted for brevity> Again, thanks for your positive response and I look forward to further discussion after the holidays. Best wishes in the coming year. Regards, Kent ------------------------------------------------------------------------------ Learn how Oracle Real Application Clusters (RAC) One Node allows customers to consolidate database storage, standardize their database environment, and, should the need arise, upgrade to a full multi-node Oracle RAC database without downtime or disruption http://p.sf.net/sfu/oracle-sfdevnl _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
