Advanced Search

For what I want to do, the script boils down to

echo 2 > /proc/irq/29/smp-affinity

I've tried this and it doesn't work. I get "permission denied" (whether or not I use sudo), presumably because folder irq don't exist. And even if I were to create folder irq, and create a folder 29 within it, I can't see how just creating a file is going to change anything. Something has to use the file, and in this case I think that that something is irqbalance, which as I've mentioned doesn't exist and can't be made to exist.

You might try this script to pin the Ethernet interrupt to the last CPU

 

chmod +x pinirq.txt

sudo ./pinirq.txt enp1s0

(might also be enp1)
 

Yes, isolcpus is set to 1.

I think that the ping test is a smoking gun.  If the results can be explained and a solution found I suspect (hope?) that everything else will fall into place.  The attached is typical:



It's beyond belief that a round trip that typically takes about 0.1 ms can sometimes take 26ms.  And note that the round trip clearly took more than 1ms quite a few times (the total test took more than the 60027ms it would have taken had there just been one bad ping).  What could possibly be causing this to happen?  It's not as if anything else was going on - apart from the test the computer was essentially idling.

I've paid my $2 Australian and have had a crack at IRQ affinity.  But the solution proposed in the forum piece is of absolutely no use to me.  irqbalance was not even active on my machine, and when I tried to install it it would not activate because the condition "CPUs=>1" was not met.  Which does make sense - if you've only got two CPU's and you're not going to allow interrupts on one of them there isn't much scope for balancing. In practice interrupts are distributed between the two CPU's (note: they are evidently NOT excluded from the isolated CPU).  See the attached file.

 

Presumably my goal  should be to tie interrupt 29 with CPU 1 and all other interrupts with CPU 0.  But how can this be achieved?  I don't even have a /proc/irq folder, and even if I did I suspect that in the absence of irqbalance creating appropriate files wouldn't do me any good.  And presumably I should also be running the ping test on the isolated CPU.  Does the 99 priority force this to happen, or is something else required?

 

It's more of a kernel/driver issue than hardware/Linux Distribution issue.

Are you using isolcpus?

 

The ones on page 9 and 10 only.

The cia402 module will do the right thing with controlword and statusword, you should not need to do anything yourself.
The drive needs to be in OP first.

You can try with 2 ms, I guess. Should work too.
 

Include all pdo entries even the ones you don't use.

Do I need to configure all pdo entries for all 7 modes? (1600 1A00, 1601 1A01, 1602 etc)

It also says the bits are unique for each operating mode; do I also need to configure the individual bits of Controlword to achieve:
"The servo must be Enabled before it can follow any command. Enable
the servo by turning on bits 1 and 2 of the Controlword (Ready to
Switch On) then turning on bits 0-3 of the Controlword (Operation
Enabled)." 
This is stated multiple times, including page 12, 13, 15 and 26

Setting "sync0Shift=700000" didn't seem to change anything that I can see

Could I just change the configuration to 2ms?


 

"As I said 2 cores may not be enough anymore"

Why does Microsoft come to mind here? Doubtless the folks at Debian would say that Bookworm is an improvement on Buster, but I'd question how a system that may require more advanced hardware to do exactly the same job can be called an "improvement". I'm quite happy with my little industrial PC. It's a perfect fit for my workshop environment (small, fanless) and experience has proved that it is quite capable of running Linux CNC. So to my mind the problem is not my PC but Bookworm, and if all else fails I'm going to simply revert to the Linux 2.8.2 Buster distribution and accept that my system will have to stand pat as the Debian world moves on. End of rant.

1. yes
2. no
3. wire the power to Mesa, wire step and dir pins from Mesa to drives.
That part is very simple, so start with that and we will help with whatever comes next.

Looks pretty cool Alan!

there are a few Intel N100 PC's put there with multi Intel NIC included. Some also have rs485 with terminal input. I would go with that in preference to the Odroid to get away from the realtek card.

Surely you can have that document as an attachment?

Hello everyone,I’m working on a LinuxCNC + EtherCAT setup and I’d like to ask if anyone has experience using the Leadshine R3EC EtherCAT coupler together with the R3-0808-N expansion module (8 digital inputs + 8 digital outputs).if so can please anyone share the XML configuration file with me ?

I have been testing LCNC on the pi with the nvme hat and PoE, until I realised that the integral RJ45 will be for the ethercat network and wont have PoE!! A bit of a misstep there. In a raspi environment the waveshare addon does complain about limited current availability and the shutdown of peripherals.

Less keen on the Rpi5 now because I realised it has integral wifi, my intention is for a product and adding wifi means I have to satify requirements of RED, so I even more so am interested in alternatives. The Odroid is looking more promising!

Hakan wrote:

You should apt remove r8168 driver or it will take that one.
Best to check though, I might not remember this right.

No keep it. It is the correct driver for the R8111
Ref: packages.debian.org/trixie/r8168-dkms

Never remove the driver, always purge it as mentioned on that link

As I said 2 cores may not be enough anymore
 

Hi everyone,I’ve been working on a CNC project for a while and I’d like some advice before committing to hardware. Here’s my situation:

• I originally built a 3-axis CNC router running on GRBL (ESP32) + a custom PCB. I used that setup for a long time and gained good experience with it.
• Later, I decided to upgrade to 5-axis by adding A and C axes to the same GRBL-based system. While it functions, I quickly discovered a limitation: ESP32 GRBL doesn’t support TCP, so the machine can’t act as a proper 5-axis system.
• Because of this, I started looking into LinuxCNC. At first I wanted to use my Raspberry Pi 5, but I read that the Pi version of LinuxCNC can’t really handle full 5-axis control.
• I then tried installing LinuxCNC on an old laptop, but since it has no parallel port, I searched for hardware solutions that use Ethernet. That’s how I found Mesa boards.

From what I’ve gathered so far:

• The 7i76 series supports 5 axes and spindle control, but its encoder inputs are only for the spindle, not for axes.
• The 7i95 series seems more suitable because it supports encoder inputs for the axes as well. My thinking was that even though steppers usually work fine, it would be good to have encoder feedback to check for missed steps.

Where I’m at now:

• When testing LinuxCNC setup, I couldn’t find any 7i95 options in PNCconf, which left me confused.
• My current hardware: 2.2 Nm NEMA 23 steppers with DM556 drivers on all axes (6 motors total, since Y has dual rails).
• I don’t have encoders yet, I was waiting to see which types are actually supported by the mesa boards.
• As another option, I do have a couple of 400 W Delta B3 servos, but not enough to equip all axes. I’ve considered using them if steppers turn out too weak, but that would mean buying more servos.
• My main goal with encoders is simply to check for missed steps on the steppers.

My questions to the community:

1. Am I on the right track with the 7i95 + LinuxCNC setup for a 5-axis machine with encoder feedback?
2. Would you recommend a different Mesa board or configuration for this?
3. Are there any guides/resources for setting up a 4+ axis machine with Mesa boards and LinuxCNC?

Thanks in advance for any advice!Ozan T.