rodw wrote:

Note that CNC is a small subset of Ethercat use as the majority of devices are deployed in factory automation. There are other field bus technologies mentioned in the PDF (and perhaps Mesa's hm2_eth driver) that compete but they are based on standard TCP/IP packets and while Ethercat also uses TCP/IP (perhaps TCP/IP are the wheels on the train). But Ethercat is much more efficient (lean) protocol so it performs better.

A small correction here, Ethercat does not use TCP/IP but instead uses 'raw' Ethernet frames.

Another technical reason Ethercat is fast is that the slaves use custom Ethernet chips which can handle process data 'on the fly' without introducing delays.

bobwolf wrote:

Subject: Solving the USB Latency Dogma for HMI/MPG: Technical Feedback Request

Hi all,

I’d like to open a technical discussion about a project I’ve been working on, io_decoder, focusing on the software solution I've implemented to handle USB communication within LinuxCNC.

 

+1
More hardware support for LinuxCNC.

I am very much interested in this project. I have experience with embedded mcu applications, but zero experience doing development with the USB stack. Last year I was thinking that this type of I/O via USB connection should be developed, but did not find time to start on it.

I like the mechanical format of your boards, for edge-mounting them on a DIN rail.

Ethernet is very good for EMI prone applications, however, there are plenty use cases with less EMI where USB is just fine. For example, I have LinuxCNC reading an industrial position sensor through a cheap USB to RS232 dongle going on about 10 years by now. It substitutes for an encoder, providing feedback for a relatively slow moving PID controlled axis. This is on a setworks on a lumber mill, to set board thickness. The only interference problems they've had was of a mechanical nature, when a log jams in the wrong spot and rams the $2500 USD magnetorestrictive position sensor. It gets all bent out of shape, but lasts more than 5 years.

Got it .  Spindle running and all axis running now just need to tune axis and get limits and encoders set up this is amazing after so many days I think this is going to be worth it because I have more of these conversions to do and I have learned so much it is amazing.  Without even tunning the spindle is behaving really well with no feedbac yet.  I was having trouble in uccnc wtih overshooting and taking awhile to get settled.  Has anyon e noticed smoother operation with linuxcnc vs other s when they switched?  The exciting thing for me is the prospect of ridgid tapping.  .  My liimit switches are only two wire.  Is this going to work?  I have a threee wire home swithc set up hall sensor
 

Mit dieser Anpassung sollte das vollständig durchlaufen

    #2 = [#2 + 1]
   #1 = 0
o101 endwhile

7I76EU firmware for 7I85 on P1, and 1 PWM on P3

 


After doing this I also had a thought that you could use a spare RS-422
output on the 7I85 for the PWM output, so you get a  buffered output
rather than a bare FPGA pin.

 
 Thats a dodecadon lol
I was planning to make rounded corners actually be radiuses in the gcode G2 G3, probably next week, unless you want to oblige, many thanks again Rüdiger!

Reply to PCW with:
"Yes, that's correct:

7i85 encoder card on P1 (first DB25 expansion connector)
PWM on P3 (second DB25 expansion connector) for laser

Or if it's easier, PWM on P1 and 7i85 on P3 - whichever works best for the firmware. i use all 5 stepper outputs. so any port or pin you think is best will do.

I'm a little unconvinced how changing to USB would have an affect on the "wiring nightmare or EMI issues".
At the end of the day one still has to make a connection from the input or output device on a control panel to the interface board.
The wiring nightmare and/or EMI issues will be a creation of the practices used by the person doing the work. In summary these issues are going to be site specific.
From memory Mesa did have a USB interface board, but is now listed as obsolete. It also supported EPP, only mentioned for completeness.

Ich versuche gerade eine while Schleife in einer while Schleife zum laufen zu bringen, die äusere Schleife wird nur ein mal ausgeführt,.

nc-code

F10000
#<radius> = 10
#<anzahlEcken> = 3
#<winkel> = [360 / [#<anzahlEcken>]]
#<verrundung> = 0.001
#<drehungUmC> = 60
#<wiederholungen> = 5

G10 L2 P1 R[#<drehungUmC>]
G64 P[#<verrundung>] Q0.0
#1 = 0
#2 = 0

o101 while [#2 LT [#<wiederholungen>]]
    o201 while [#1 LT [#<anzahlEcken> + 1]]
        g90 g1 x[COS[#1 * #<winkel>] * #<radius>] y[SIN[#1 * #<winkel>] * #<radius>]
        #1 = [#1 + 1]
    o201 endwhile
    #2 = [#2 + 1]
o101 endwhile
m2

ist es überhaupt möglich ?

Gruß
Rüdiger
 

I am working on integrating my first analog servo build. 7i97 and Anilam drives. I am following the steps here . I have the encoder scaling correct but when I go to enable the machine, there is a brief moment of runaway before I get two errors: 
"joint 1 following error"
"could not switch the machine on. is limit switch activated?"

I am only working on joint 1 at the moment. 
No limit switches are in use at the moment. 

I have tried inverting 'output scaling' and 'encoder scaling' in every possible combination on the configuration page. 

Any suggestions? 

Thanks! 

Do you mean 7I85 on P1 and PWM on P3  (on 7I76EU P1 is the first parallel expansion connector and P3 is the second)

Very interesting. A few points.
1. You don't say anywhere how to get the boards which are very well thought out. I'd love to test it.
2. New software to go into Master branch (2.10) which will be released in a few months.... This needs to be tested on this version (I'm finalizing a how to build linuxcnc video on my @MrRodW YouTube channel
3. Reformulate (or recreate) the git repo so this can be packaged as a PR to Linuxcnc. This would give you the best chance of success with your hardware project.
4. Your business model is similar to Mesa's so having an open source driver for your hardware in the Linuxcnc distro is not really controversial.

I revised the NC program and made the number of corners and the radius parameterizable.

Hi PCW,

I need custom firmware for 7i76EU with:
- 7i76 daughter card on internal SSerial (currently working)
- 7i85 encoder card on P2 (currently working)  
- PWM generator on P1 for 20kHz laser control



Can you create firmware combining all three?

Board IP: 192.168.1.121
5 axes: XYZAB vfd rs485 controls spindle direct on the mini pc with rs485 output

Thanks!