As pointed out in https://www.robotshop.com/letsmakerobots/changing-pwm-frequencies-arduino-controllers the frequency of the PWM for the motor controller might be an issue.
I am using this motor controller: Dagu 4 Channel 5-12V, 2A Brushed DC Motor Controller https://www.robotshop.com/en/dagu-4-channel-brushed-dc-motor-controller.html actually it looks a bit different:
but I assume that both are the same.
I was not able to find technical data, what frequency for PWM input this motor controller can use. Is there some more technical description of this controller?
The Spider Robot Controller uses e.g. 490.2Hz on pin D44, D45, D2, D3, D5. 976.5Hz on D4. At least that’s what I have tested. Are there pins with higher frequency that I should avoid? Is there some technical description mapping frequency to pins (factory setting)?
I connected the current channel of the 4 Ch Motor controller http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/4%20Channel%20instruction%20manual.pdf with the analog input of the Spider controller and measured with e.g. 90 PWM duty cycle “41”. Did I understand that correctly that this is 41 * (5V/1024 (= 10Bit resolution)) = 0,2001953125A which means the motor draws 0,20A with this PWM duty cycle?
If the motor runs forward at PWM duty cycle 30 it shows 0.09A this way. PWM 30 -> 0.10A backward PWM 200 -> 0.23A forward PWM 200 -> 0.25A backward and so on.
If it stalls it shows max 0.12A with PWM 30. As far as I understood the whole thing the current measurement with the 4 Channel Motor controller should go up to 2.5A . Is the stall current measurement different for different PWM duty cycles because of PWM?
