pwm schematic help required please?

[Tel 27]

Hmmm, looking at that you might want to take up Italian cooking, to make sense of that spaghetti :). <-- intended with tongue in cheek

Okay, I don't know your BoB - but looks pretty generic. That makes me think that the "outputs" from the controlling PC will be buffered with the two large chips (74HC244s?) - they'll be able to drive the PWM output low enough to activate the opto-isolator, and so *should* work (or at least not blow anything up). Suck it and see. My other comment was thinking that if, and I don't know about this, but if the BoB doesn't output the standard PWM pin out, but instead only provides the resulting analogue drive, then instead of trying to route the standard PWM, use the other outputs that are associated with the typical 4/5 axis drives on the BoB - as these are easily available (and from within Mach its easy to remap the PWM output to any pin).

My conversation about arduinos is simply to take an unknown (mach) out of the equation to help better understand how to drive the speed controller, but I'm presuming - perhaps too much - that that's in your interest/comfort zone. It's nothing to do with CNC but would be a great way to test the board in (almost) isolation.

Truth be told the whole electrical thing is outside my comfort zone!

I've no problem with programming and machining, (been doing that since I left school in 79') but electrics are a mystery to me!

This is a sketch of how the potentiometer was previously wired up - I think its incorrect, looking at previous comments, there is NOTHING going to wire 3 (this was merely cut off), and it sounds like wire 3 is the ONLY way the PWM output can connect to the controller board? (with or without the potentiometer in the circuit)

I'm at a bit of a loss here - is there anyone in the UK who could take a look at it for me?