On Thu, 2008-04-17 at 18:21 -0400, John Kasunich wrote: > Kirk Wallace wrote: > > On Thu, 2008-04-17 at 14:30 -0700, Curtis W. Moore wrote: > >> My HobbyCNC board says it is a "Unipolar Chopper Control" > >> > >> It does 1/2, 1/4, 1/8, 1/16 microstepping. Uses 6 wire (2 common) > >> steppers. > >> > >> C > > > > Thanks Curtis. Thats looks close. Too bad it has a 3 Amp max. I need > > around 8 Amps with slightly more voltage (45 V). > > > > If you are thinking about replacing the drives, I'd go with Geckos. > They are bipolar, but you can set use your 6-wire motors in series or > half-winding configuration. > > Do you know your motor's rated current and voltage (not supply voltage, > winding voltage, determined by multiplying the rated winding current by > the winding resistance). > > Regards, > > John Kasunich
There is no data attached to the motors. I measured 1.1 Ohms across each coil, with 1.0 Ohms across the leads, so the coils are somewhere around .1 or .2 Ohms. The 8 Amp figure comes from the driver circuit board where the current limit potentiometer indicates an 8 Amp max. Is any of this useful? I scoped the driver board inputs again and corrected my signal diagram on the schematic. The gray traces are the result of the coil input and it's inhibit. I confirmed this with scoping the far side of the input optocoupler. I played with the axis speed and noticed the inhibit gets smaller and goes away around half speed. The trace leads me to believe the designers were trying to soften the low speed steps, with a brief half step, so that the motor would not overshoot and degrade the surface finish. If this is the case and not for some sort of electrical reason, I can switch over to EMC2 right away, and not worry about blowing out a board. Of course Stepgen doesn't have this inhibit signal available, so I may need to find another way, maybe using selective and adjustable delays in HAL. If step overshoot is a common stepper problem, is there a common way to fix it? -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending Craftsman AA 109 restoration Shizuoka ST-N/Bandit CNC) ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
