On Saturday 16 August 2008, Sergey Izvoztchikov wrote: >Anyone has experience with this board ? Is it known product or new >board ? Any pros and cons ? Is is going to work under EMC2 control ? >Would it be a good choice for Sherline Mill CNC retrofit ? > >http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230280442519&ssPageN >ame=STRK:MEWA:IT&ih=013 > >There is some info about PWM signals shape. Is it enough to configure >EMC2 properly ? Here is link to board specs -
I think emc could drive this board, but I'd have some concerns. 1. The chopper frequency is fixed at 12 kilohertz. This seems a little low, and could lead to magnetic saturation of the motors, which in turn causes quite large currents to flow at the end of the on cycle when the pwm is at maximum width. And as emc itself can, on barn burner cpu's reach nearly 10 kilohertz step rates, I could envision step loss problems could be generated at high step rates. At its relatively course step rates, resonance dampers are going to be needed although the actual speed will be much (4x/8x) higher than a xylotex at its default of 1/8 step. I found dampers to be a huge help even with the 1/8 step of the xylotex. >http://www.soc-machines.com/pdfs/MC433%20Hardware%20Technical%20Manual% >20R11b.pdf > >And here are motors to go with this board - > >http://cgi.ebay.com/3-High-Speed-NEMA23-125oz-in-Stepper-Motors-SM3006B_W0QQ >itemZ330262184558QQihZ014QQcategoryZ71394QQssPageNameZWDVWQQrdZ1QQcmdZViewIt >em Which seems a little odd. Using an amplifier capable of 33 amps peak, 10 with normal cooling, with a motor this small (3Amps max) seems to be a miss-match to me. This board would be at home driving a 20x stronger nema 42 motor given good cooling. Bear in mind my experience is with the xylotex board, not this, or Gecko's, so my thoughts are colored by that. It does seem like a viable driver for bigger motors than the 125's the above link leads to. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) To be sure of hitting the target, shoot first and, whatever you hit, call it the target. ------------------------------------------------------------------------- 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
