On Thu, Jul 2, 2009 at 7:59 AM, Jeff Epler <[email protected]> wrote:
> On Thu, Jul 02, 2009 at 08:41:23AM +0200, Denis Stremplewski wrote: > > Hi, > > Does exist a way for automatically shutting off the power of the motors > at > > the end of a program (something like Mxx), in order to avoid a self > heating > > of the motors ? > > You don't want to do this. > > In a stepper system, any time you turn off the amplifier you risk losing > position. That's because when you turn the amplifier back on, even if > it powers on in the same phase as it powered off, it might pull in to a > spot +-4 full steps from where it was powered off. Furthermore, there's > no warning before an interactive jog can begin, so you can't make sure > that the amplifier has had a chance to turn on before the first step is > made. Any time the amplifier is turned off in a stepper system, you > should assume that you have lost position and need to re-home and/or > touch off again. I am using the HobbyCNC pro board which has Idle Current Reduction on the drive chip (SLA80something). I bypassed each driver's timing circuit and wired the trigger lead directly to one of the parralel port pins. I then used the Amp Enable option on the Stepconf wizard. Will this set up lead to the kind of misqued steps you note above? I personnally have not noticed any drift on my steppers, but then again, I do not use it often. Prior to bypassing the timing circuitry, I constantly had issues with the Z axis losing position with long 2.5D cuts. Thanks. Brian ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
