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General Mach Discussion / Help Please with PWM Spindle Motor Speed
« on: November 16, 2014, 07:23:09 AM »
I suspect you may have a couple of basic problems. First it is likely that the PWM speeds controller you have need a voltage between, probably, 0 and 10 v to set motor speed. However to confirm this you need to provide more than a photo, we need to have its specification or a link to one.
Second, you don't say how your PC is connected to the controller. Assuming you have a breakout board, the PWM output from this is just a train of 5 volt (usually) pulses of varying mark/space ratio, which needs converting to the control voltage. Again, we need to know details of the BoB to confirm this. Unless it does the conversion internally you would need something between it and the controller to do it, it's only a simple circuit and several have been published.
Third, the PWM base frequency you have set is far too high by a factor of 100. Something like 25 to 50 Hz is better to get smoother control.
Once you have this working the pulley ratio is irrelevant as your spindle doesn't have pulleys.
Please give us more information, on the breakout board type and controller type!
Sent from my iPad using Tapatalk
Second, you don't say how your PC is connected to the controller. Assuming you have a breakout board, the PWM output from this is just a train of 5 volt (usually) pulses of varying mark/space ratio, which needs converting to the control voltage. Again, we need to know details of the BoB to confirm this. Unless it does the conversion internally you would need something between it and the controller to do it, it's only a simple circuit and several have been published.
Third, the PWM base frequency you have set is far too high by a factor of 100. Something like 25 to 50 Hz is better to get smoother control.
Once you have this working the pulley ratio is irrelevant as your spindle doesn't have pulleys.
Please give us more information, on the breakout board type and controller type!
Sent from my iPad using Tapatalk