On Sun, 7 Dec 2008, Len Shelton wrote: > Date: Sun, 7 Dec 2008 10:55:50 -0600 > From: Len Shelton <[EMAIL PROTECTED]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "'Enhanced Machine Controller (EMC)'" <[email protected]> > Subject: Re: [Emc-users] microstepping stepper power drive > > If you read that whole post, you'll share everyone's disappointment. > Apparently there is a bug in that chip that causes incorrect microstep > angles and Allegro is unwilling to admit it or correct it. > >> Len
Ah yes, I got all excited when that chip came out and built a 2 axis daughter card for our Anything I/O cards (6A 50V) (the 7I41). The problem is that the chip changes current control mode depending on whether winding current is increasing or decreasing. While this may be appropriate for high speed operation, it causes major current errors while stepping slowly. So we dropped the 7I41. Allegro has a replacement the uses SPI instead of step+dir but I lost interest. We will have a low cost step motor drive based on a DSPIC some time next year. > > > > -----Original Message----- > From: BRIAN GLACKIN [mailto:[EMAIL PROTECTED] > Sent: Sunday, December 07, 2008 10:48 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] microstepping stepper power drive > > Perhaps this discussion will offer something to you. > > *New Allegro Bipolar Stepper Driver A3986* > http://cnczone.com/forums/showthread.php?t=24699 > > Opening post suggests 10A at 50V. Have not had the time to read the entire > set of posts. > > On Sun, Dec 7, 2008 at 10:23 AM, Ian W. Wright > <[EMAIL PROTECTED]>wrote: > >> >>How many wires do your motors have? >> >>Len >> >> One has 8, the other 6 so it doesn't really mater whether >> the drive is unipolar or bipolar. >> >> -- >> Best wishes, >> >> Ian >> ____________ >> Ian W. Wright >> Sheffield UK >> >> "The difference between theory and practice is much smaller >> in theory than in practice..." >> >> >> > ---------------------------------------------------------------------------- > -- >> SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, > Nevada. >> The future of the web can't happen without you. Join us at MIX09 to help >> pave the way to the Next Web now. Learn more and register at >> >> > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > ---------------------------------------------------------------------------- > -- > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. > The future of the web can't happen without you. Join us at MIX09 to help > pave the way to the Next Web now. Learn more and register at > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------------ > SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. > The future of the web can't happen without you. Join us at MIX09 to help > pave the way to the Next Web now. Learn more and register at > http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
