Perhaps a more significant advantage of the servo drive described by John Dammeyer is that it has a current control loop running inside of the LinuxCNC velocity control loop. Pretty fancy to do that on an 8-bit microcontroller. That ATTiny has an on-chip analog comparator.
> On Oct 15, 2020, at 10:03 PM, Jon Elson <[email protected]> wrote: > > On 10/15/2020 09:49 PM, John Dammeyer wrote: >> The theory is that if the PWM signal is high the H-Bridge is switched to say >> turn the motor clockwise. If the PWM signal is low the H-Bridge is switch >> to turn the motor counter clockwise. Therefore with 50% the motor is first >> asked to turn one way and then the other. That results in the motor >> essentially being locked in place. Change the PWM on either side of 50% and >> the turns in the subsequent direction. > This is called synchronous antiphase. The advantage is there is no dead zone > around zero. > The DISadvantage is it causes a triangle-wave current in the motor which can > be quite substantial, > and causes excessive heating of the motor and power transistors. > > Jon > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
