EMC2 running on Raspberry Pi?

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21 Apr 2014 21:23 #46175 by ADBensi
I know nothing of your settings, but in your config file this with an appropriate value for CYCLE_TIME of DISPLAY? Did You tried to tip your X environment and open the application via SSH?

I use .25 ms over SSH and have no problems with the buttons, it is slow for activities that consume CPU and will not maintain the minimum time 2mS for signal of steps over GPIO Direct.

It is the opposite of its :D

I still have my Xenomai image on google drive if you want to test with Xenomai on this pass me the email for sharing.
Best Regards

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22 Apr 2014 00:42 #46187 by andypugh

I found that for some reason I could not drive motors at more than 1500rpm (according to my rpm meter) this would be a pulse frequency of 5000 pps, 25us should allow 20000ppst.


This could be a physical limit. 1500rpm is very fast for a stepper motor.

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26 Apr 2014 05:37 #46329 by mungkie

I found that for some reason I could not drive motors at more than 1500rpm (according to my rpm meter) this would be a pulse frequency of 5000 pps, 25us should allow 20000ppst.


This could be a physical limit. 1500rpm is very fast for a stepper motor.


Its not a physical limit unless its a driver physical limit where the driver stops sending pulses higher than a given frequency, as far as I am aware normally driver will continue sending pulses but motor will stall but it is still possible to tell that the step frequency is increasing as the vibrations can be heard increasing in pitch.

The problem I am finding is that the motors reach a maximum speed and do not go beyond that speed or stall and give any higher pitched sound regardless of the feed or jog override set in axis, I probably have not setup the hal config properly.

I will look into it further once I have fixed the usb input lockups.

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26 Apr 2014 05:49 #46330 by mungkie
I just thought I should say it looks pretty good for a 'reasonable' linuxcnc system running on the raspberry pi, where reasonable means step rates comparable to arduino based reprap printer firmwares.

I have been messing about with kernel configs and updates and it looks like the input lockups could be fixed, so I am guessing it could be only 100 hours programming and debugging to get the driver polished with gpio input and output.

I just need to do some final tests on kernel performance and latency under load so I am sure that its possible to get decent performance, then I will start a kickstarter project to fund the final development of the gpio driver.

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24 May 2014 02:18 #47265 by ADBensi

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11 Jul 2014 23:21 - 11 Jul 2014 23:22 #48658 by mungkie
I have been thinking about trying to finish off the drivers and creating a distro for linuxcnc on the rpi but cannot workout how it would be possible to fund it.

My idea is that there are probably too few people that would support development, but if I could create a full package of parts to create cnc motors and drivers with interface that any beginner could make in a few hours and would run a sherline or 3dprinter at cheap ~£75 cost, maybe there would be enough people interested.

Unfortunately getting components at a reasonable cost means higher volume bulk purchase. So I think it probably unlikely that would be funded either but I am going to try a kickstarter for it anyways.

I show below the assembly/setup of the electronics I have sourced, the motors and power supply I have not finalised with suppliers yet.

If anyone is interested in further information read the information on the youtube video page.

Video shown below:

Last edit: 11 Jul 2014 23:22 by mungkie.

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12 Jul 2014 03:23 #48666 by tenaja

I have been thinking about trying to finish off the drivers and creating a distro for linuxcnc on the rpi but cannot workout how it would be possible to fund it....

I am not trying to be a buzzkill, but when you can use a ready-to-go version of LinuxCNC on the stock beaglebone black, which is noticeably faster than the Pi, why even bother?

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12 Jul 2014 09:20 #48679 by andypugh

I have been thinking about trying to finish off the drivers and creating a distro for linuxcnc on the rpi but cannot workout how it would be possible to fund it.


One way would be to do it and simply not fund it. ie just treat it as a hobby, and give away the results. Like cross-stitch, except nobody wants cross-stitch.

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15 Jul 2014 07:43 #48788 by ADBensi
Mungkie, perhaps the lack of an interest in financing is because the RPI + LinuxCNC is limited and does not arouse the interest for commercial use. So, it is preferable go to BBB or X86 PC. This work with RPi is very important to the community. I think to call attention the board should be better than BBB.

For sample,

I am walking with ODROID-U3 + LinuxCNC + RT Kernel as a hobby. I'm using version 1 without SPI and I can say that is very close to a conventional computer (around 1.2GB of memory with full load of CPU quadr-core during a convertion: 20 seconds on Odroid and 15 minutes on RPI to convert image to Gcode) At the moment I just need hal SPI driver (the maintainer of hardkernel / ODROID released version 2 of ODROID-U3 with SPI pins, they are very understandable, I'm hoping my buy).

I'm not saying to change the board, just my point of view across your comment.

Best Regards Mungkie

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15 Jul 2014 08:46 - 15 Jul 2014 08:50 #48790 by vre
Replied by vre on topic EMC2 running on Raspberry Pi?
I haven't read the thread but this seems a better board than rp and bb
check it cubieboard.org/2014/05/04/cubietech-will...performance-mini-pc/
www.flickr.com/photos/125001602@N03/sets/72157645370517326/
Last edit: 15 Jul 2014 08:50 by vre.

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