On 5/24/20 6:29 PM, andy pugh wrote:
On Mon, 25 May 2020 at 00:17, R C <cjv...@gmail.com> wrote:
I have been following this thread. I wrote some code that runs on an
RPI that can read a quadrature encoder, I have a few of them, with
different resolutions.
Is this something different to the normal LinuxCNC software encoder
that reads GPIO?
Is there some dedicated encoder counter hardware on the Pi?
Oh I am not running linux cnc on an rpi, I run it on a server "class"
machine. I was just curious about how these encoders work, and why
they didn't
work that well with my linux-cnc setup using a db25 BOB with the 2
benchtops I have.
So I decided to use an RPI (because it is easy to use GPIO pins to read
signals) and write some code to read these encoder signals.
So I guess my answer is yes, it is different from, what linux-cnc
running on a pi does (I would be surprised if it was similar)
I setup an RPI, hooked up a 2 line LCD display to it to display rpms,
wrote some interrupt driven code that reads the encoder and displays it
on the LCD. The idea is, I want
to try and see if I can read the encoder and then send signals back to
linux-cnc that it 'could handle".
So I have a 60ppr encoder, 60 has a lot of dividers. 2, 3, 4, 5, 6,
10, and 12 So if I can "transfer" a pulse with a consistent delay
exactly when the actual n-th pulse
comes in, I could turn a 60ppr encoder into a 30, 20, 15, 12, 10, 6 or
5 ppr encoder by just skipping pulses, while raising some GPIO pins,
that I connect to the BOB, when
I read a different set of GPIO pins directly from the encoder.
But as I said earlier, I don't know a lot about the linux-cnc's
internals, and HAL, but it is something I am playing with to see if it
could work.
Ron
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