What is the frequency of the PWM signal for extruder and hot bed ?

Hi..

What is the frequency of the PWM signal for tjhe extruder and hot bed ?

I had some THERMAL RUNAWAY's.
Marlin stopped it. No fire :-) Thank you Marlin Makers.

Now i want to keep an eye on the PWM signal of the extruder by connecting the extruder wires to an arduino.
Before and after the connector.
Via a optocoupler. Not electrically connected.
And measure the temperature of the extruder.
To see what is going on.

But i do not know if the arduino digital input is fast enough to measure the PWM.

That is why i want to know :

What is the frequency of the PWM signal for the extruder and hot bed ?

Thanks..
Windchime

Edited 1 time(s). Last edit at 03/12/2023 03:56PM by windchime.

Looks like 1000 Hz is the default for the heaters.

This link says:

"....the PWM frequency is 7.689 Hz"

https://marlinfw.org/docs/configuration/configuration.html

I think a arduino input can be read much faster.


Windchime.

The tiepie tp5008 osciloscope shows the PWM frequency of the marlin 2.1.2 hotbed is about 7 Hertz.

Nicely long, which gives the arduino inputs a better change to do enough readings per PWM period.