Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: NosmoKing on November 19, 2021, 03:43:52 PM

Title: Mach3 PWM stability under Windows
Post by: NosmoKing on November 19, 2021, 03:43:52 PM

For those that have 'scoped the PWM signal, how much fluctuation was seen, either frequency or pulse width.
If so, at what set frequency?

Title: Re: Mach3 PWM stability under Windows
Post by: joeaverage on November 19, 2021, 06:19:30 PM

Hi,
PWM stability is pretty good if you use an external motion controller like an ESS, but not so good with a parallel port.

PWM is handled by dedicated hardware with an external motion controller whereas a parallel port is relying on a interrupt driven timer.
Windows makes extensive use of interrupts for its internal use and consequently interrupt driven timers fare poorly.

Craig