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Originally Posted by Adam Y.
Does it affect anything that the motor is an analog device and needs an analog signal (PWM)?? It's pulse position modulation for the incoming signal not pulse width modulation. Pulse width modulation is the signal that controsl the motor.
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Adam,
That's kind of the beautiful things about this control. It is a digital signal, running from +12 to ground, that is converted to an average mechanical power with no real active circuitry. The motor does all the conversion with a little help from physics (conservation of momentum) and a little from electrical (inductance) etc.
The control signal and the output of the controller are both PWM. Pulse position signal uses the same size pulse but varies it's position in relation to a reference. In PWM the pulse width varies over the time of a single cycle but the cycle length doesn't vary. That makes it sort of self clocking in that for the most part there is a start and end to the pulse cycle. (about 2 kHz) The output PWM is not an amplified version of the input. The input pulse width varies over 255 steps where the value (width) of 127 represents no motor current at all. A "0" will make the output turn on to full 12 volts (no PWM) and a 255 will do the same but reverse the leads (+12 becomes common and common becomes +12 to the motor) which reverses the direction of the motor.