• Not really an update

    rstevenson2309/20/2015 at 00:27 0 comments

    Hey guys,

    Not really an update but just thought I'd throw up a video of motor encoder counts being sent over ethernet.

    Still stuck on the Linux part. Found out that the hardware that i have is not compatible with RT-Net unless I create a driver for it. So i have to find some other network card that uses a e1000 or r8168 driver for linux. Any ideas where i can get such an ethernet card?

  • Progress is slow

    rstevenson2302/11/2015 at 01:59 0 comments

    Slow and steady wins the race right? I'm for sure slow but steady? Not so much.

    I am able to communicate between my linux laptop and the STM32F4Discovery board with a Waveshare DP83848 Ethernet board. The Ethernet board can be easily found on Ebay or Amazon for around $5-7ish.

    My build will be mainly geared around servo control since I want to use servos instead of steppers but could easily be modified for stepper control. It would probably be easier with steppers since you wouldn't have to send position/velocity feedback back to the PC. Either way i hope to keep this easy enough to change between Steppers and Servos or a mix of both.

    Okay, progress update. I am so far able to send to the PC X, Y, Z position from quadrature encoders. I currently only have one encoder but all three feedbacks work individually. I also am sending back X and Y axis end stop bits. The STM32F4 is receiving 3 integers for X,Y,Z duty cycle and one bit to turn the spindle on.

    When I first started this i was wondering how fast I was going to get packets to and from the STM. Well, to answer that, I am averaging 93us for a send and receive. I have been getting spikes of up to 12ms but I believe thats because I am constantly sending and receiving. I am hoping that once is switch to real time networking and sending/receiving every 1ms, I wont get the spikes of 12ms.

    My next steps are to install and fiddle around with RTNet and then integrate it into LinuxCNC. I am by no means a Linux expert so progress will be slow.