Controlling feed with potentiometer
13 Jun 2015 02:23 #59758
by DaPeace
Controlling feed with potentiometer was created by DaPeace
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
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
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13 Jun 2015 02:48 #59759
by alan_3301
Replied by alan_3301 on topic Controlling feed with potentiometer
Start your reading here linuxcnc.org/docs/html/gcode/m-code.html...daptive-Feed-Control
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13 Jun 2015 02:53 #59760
by DaPeace
Replied by DaPeace on topic Controlling feed with potentiometer
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
Thanks anyways
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13 Jun 2015 03:00 #59761
by PCW
Replied by PCW on topic Controlling feed with potentiometer
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)
encoder component ( with just the 'A' pin) in HAL to read the frequency (encoder velocity)
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13 Jun 2015 03:34 #59762
by alan_3301
Replied by alan_3301 on topic Controlling feed with potentiometer
you should be able to send the potentiometer output straight to the input pin, and scale it in hal I would think.
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13 Jun 2015 03:35 #59763
by andypugh
It's _much_ easier to use an encoder. Something like:
www.ebay.at/itm/291487578363
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)
Replied by andypugh on topic Controlling feed with potentiometer
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:
www.ebay.at/itm/291487578363
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)
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13 Jun 2015 03:43 #59764
by DaPeace
Replied by DaPeace on topic Controlling feed with potentiometer
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
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
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13 Jun 2015 03:47 #59766
by alan_3301
Replied by alan_3301 on topic Controlling feed with potentiometer
Ok maybe I was steering you wrong, it looks like the parallel port pins are digital only.
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13 Jun 2015 03:51 #59769
by andypugh
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
Replied by andypugh on topic Controlling feed with potentiometer
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
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25 Jun 2015 23:13 #60132
by DaPeace
Replied by DaPeace on topic Controlling feed with potentiometer
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?
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?
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