Mach3 VFD PWM signal...

[Clive S]

Bugger, sounds about right for my luck.

But then how the heck does it manage to work at all?

Might be worth putting the 'scope on it?

A telescope won't help

[cropwell]

I think he meant a proctoscope

[Clive S]

I think he meant a proctoscope

I think you meant a endoscope

[cropwell]

I think you meant a endoscope

No I meant a proctoscope ! Happy Easter Clive..


Serious suggestion now - If you have an analogue meter these can have impedances as low as 5000 ohms per volt. All electrical measuring devices draw current from the circuit and this affects the circuit (experts can get precious here, but I am simplifying !). Having said that, I would not expect the BoB to be such a high impedance source as to have a drastic voltage drop when meter is put on it.

As Jazz says, it could be a dodgy Bob. I have never met a Dodgy Bob, but I do know a bloke called Dodgy Dave.

[Clive S]

Yep happy Easter Rob I was just jesting Avo 7 days and valve volt meters.

[Davek0974]

LOL:)

Anyways, I disconnected the BOB from the VFD and I can get sensible measurements from 0 - 10v so it seems the BOB is fine, the output is not linear though.

When connected to the VFD, no voltage again and the motor stops as soon as the meter is connected.

Very odd.

I did make a lookup table of speeds so I can easily set what i really want even though its not what it displays.

[routercnc]

If you only use a few speeds to cover your jobs I wonder if a relay module board with each relay connected to a trim pot and resistor pair from a 10v supply (each of which was fine tuned to give the right volts for that speed) could be used?
I guess you would need a gcode command in the code to switch the right relay on instead of the speed command. Just a different take on it.