Controlling feed with potentiometer

Is it possible to use one of the LPT-in to control the feed-override by a potentiometer?
Im a little in to electronics and it wouldnt be a problem to map the poti to a pwm-signal and input it with a small microcontroller.
But i didnt find any informations around the net and thought i will simply ask here..

Thank you,
Jan

Start your reading here linuxcnc.org/docs/html/gcode/m-code.html...daptive-Feed-Control

Thats not very specific. I know that its possible to use it but my main problem is that ive not found anything if it is possible to input pwm to the input-pins of the lpt and how to handle the signal.


Thanks anyways

you could use a cheap Voltage to Frequency converter (say a 555) and then use an
encoder component ( with just the 'A' pin) in HAL to read the frequency (encoder velocity)

you should be able to send the potentiometer output straight to the input pin, and scale it in hal I would think.

No eBay APP ID and/or Cert ID defined in Kunena configuration

DaPeace wrote: Is it possible to use one of the LPT-in to control the feed-override by a potentiometer?

It's _much_ easier to use an encoder. Something like:


One possibility for analogue input (that I have never tried) would be to use a PWM output into a filter, and then a comparator to indicate that the values are equal.
(so it needs an input pin and an output pin)

Oh ok. Didnt see potis like that.. thats really easy. so hooking up a poti like that to the lpt-input would be possible without additional hardware?
What configs do i need in the hal-files? is there a tutorial or wiki around where i could read around a bit?
Thank you

Ok maybe I was steering you wrong, it looks like the parallel port pins are digital only.

DaPeace wrote: Oh ok. Didnt see potis like that.. thats really easy. so hooking up a poti like that to the lpt-input would be possible without additional hardware?

Yes, you would use two inputs as the A and B phases to an encoder component in HAL.
linuxcnc.org/docs/html/man/man9/encoder.9.html

Hello.. its me again. Ive tried to adapt the code from here but i cant get it to work.
I can see that the hal-pins of channel a + b are changing while turning the encoder but the count is not counting and so the feed is not changing. Also tried with spindle-overwrite like in the example but thats not working too.
Any help in that case?
Maybe some code-examples?