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Asked — Edited
Resolved Resolved by DJ Sures!

PWM Frequency Range

What is the default PWM frequency of the EZ-B v4, and is it adjustable?

I'm sorry; I should been more precise in my question. Here is what I do know;
In a conventional analog servo motor a PWM signal with a period of 20 ms is used to control the motors.
A signal of 20 ms has a frequency of 50 Hz. The width of the pulse is varied between 1 and 2 ms to control the motor shaft position.
When a voltage is applied to the circuit the inductance of L slows down the rate at which the current rises. This happens because the inductor produces a back EMF which resists the current flowing through it. ... Therefore PWM signals using higher frequencies give less time for the current to rise.
This produces greater starting torque and less heat.

I'm going to assume that this is NOT ADJUSTABLE with the EZB and the frequency is locked at the 50Hz.

Thanks for the support.. no response required.

Related Hardware EZ-B v4


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The frequency varies between 0 and 100 (percent) with increments of 1. That varies the voltage between 0v (gnd) to vcc (on ezrobot v4 I think is 3.3v)
#2   — Edited
I may be wrong (again).

I know the PWM output voltage was adjustable, like you said, but the top PWM voltage would be whatever the input voltage is that you are powering the EZB at? Doesn't the PWM control adjust the selected digital power pin?

You can power the EZB with any DC voltage from 4.5 to 16 volts.

If I'm correct, that would variy the PWM voltage between 4.5 v (gnd) to 16 volts depending what voltage you feed the EZB? 

You can use the PWM controls found in ARC to adjust your PWM. You can also use script commands to do the same thing. 

The OP did not ask this but I think it was very interesting and important when I learned it:
Actually the voltage does not change when the PWM is adjusted. PWM actually turns off and on the supplied power output rather than limiting it. The result is that the motor slows down but still has most of the torque and current it needs. You get better performance and less heat from a motor speed controlled with PWM rather then dropping the supply voltage.
My answer explains that pwm is a range between 0v (gnd) and vcc. Which on the ezb v4 is 3.3v. It’s a range between 0-100 with increments of 1
#4   — Edited
OK, Thank for answering my question.

I think what I missed (or forgot) is what I just read in the ARC Skill store:


An EZ-B can trigger a digital port ON and OFF rapidly to simulate a TTL voltage signal low (0V) and a TTL voltage signal high (+3.3V or +5V). This method is called Pulse Width Modulation (PWM). The slider controls the value of the PWM on any digital I/O pin of the EZ-B.

If you have a motor controller (H-Bridge) with an enable port, you can connect it to a Digital I/O pin and use this skill to control the speed of the motor. Alternately, you could also control the brightness of an LED with this slider.
I think I have it now.
I saw your "no response required" edit haha, but I do have a response. Whatever custom pulse width configuration you'd like can be done using an Arduino and the EZB firmware. There is no need to use an EZ-Robot controller when you can also use Arduino or many other controllers. The getting started guide explains more. View compatible EZB controllers here: https://synthiam.com/Support/Get-Started/How%20to%20Make%20a%20Robot/computer-configuration

You can customize the controller and the EZB firmware for open-source micros as much as you need. There is never a moment where "it can't be done" can be used around here:D
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Thank You for your time, again no response was required. I have learned my lesson. one email notice for the last 33 days.