I want to control a geared DC motor for a wire feeder.
I want to use PWM to control the speed and I need to be able to significantly adjust the pwm frequency.
With PWM, you usually adjust the pulse width and keep the frequency the same. The Arduino gives a range of widths from 0 (Off) to 255 (Fully on). Is that 'significant' enough for you?
I thought it would be relatively simple to do, but when I realised the delay command messes all other timings, it got complicated.
Embrace the concept used in 'Blink Without Delay.'
I would be open to using a large stepper instead of the geared 24v motor, but i dont know how easy it would be to fit into machine (might be easy, i suppose).
That would be for you to determine, as we can't see your machine.