[FrankG]

I've been scanning for a few hours and haven't seen a clear outline of what I want to do (Already posted)...

I've built a couple of the "Generic" 5804 based controllers and worked out all the typical issues of Parallel port lines (TurboCNC is near perfect...), motor wiring and even did the Voltage boost to 12V w/Current limiting resistors...

My existing mill (3 Axis) has logged hundreds of hours, mostly because it's so damn slow... To improve it's performance, I could replace the 12V supply with a 24V unit, but I want to avoid the additional heat & wasted energy... Are there any basic parameters that a "Chopper" curcuit should follow???

I assume that it is a PWM (Pulse Width Modulator) that varies the current in some relationship to the "Duty Cycle" of PWM... I'm thinking a basic 555 timer and a few MOSFets arrayed...

Or am I being niave and missing some major component... Freq of the above PWM??? would 2Khz be too low???

Also is the performance of Steppers improved with a 5804 based controller with a faster PC... Currently I'm using an old 486DX/2 66Mhz...

These issues are not neccessarily for my existing mill as it's been slow for over a year but does it's near daily work fine otherwise, But I'm almost to the point of having to start into the electronics for a larger machine. The area that it will have to cover will definately need superior speed and likely torque for the heavier moving components...

Any advise, or comments are greatly appreciated.