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JT wrote:

Also, from time to time the forum has high CPU usage that slows down the forum but I don't know why.

DDOS and "brute force" attacks, from what i gathered.

PCW wrote:

If it's open loop, the question becomes what is changing the analog out command?

(bottom trace second plot)
 
Fixed the varying speed.. The source was the analog speed override pots, which are 5volt, being scaled to 3.3 and lastly 8 bit converted. 
I inserted a low pass filter with gain at 0.01 after the  analogin pin, and its magically stable.
You suggested this some time back, and as ever it was a good call. Thanks

I used to work with two machines that were stuck using older Ubuntu based Linuxcnc RTAI. Both ran servos, not stepper motors. One was because I could not get newer Linux kernels to work with the ISA IO card the machine was using, the other for extreme low latency to control torque mode servos. The ISA card machine was eventually upgraded to newer Mesa hardware and moved on to current Linux/Linuxcnc releases. The other is still running older RTAI.

I still have a machine running it. Needed for a low latency control for some difficult to tune torque mode servos. (So for the time being that machine is stuck on Linuxcnc 2.7)

BigJohnT used to be me and hasn't been on the forum in a long time unless someone has hijacked that account.

I have not made any changes to anything.

I don't have 100% access to everything. I can not log into the ISP hosting panel. I can log into Joomla and to Kunena and have ssh access to the forum where from time to time I do apt update. I do not know how to create a new droplet and install a new OS. I'm also not a Joomla developer so it's a bit strange to me.

Also, from time to time the forum has high CPU usage that slows down the forum but I don't know why.

JT

Hello,I've been working on this for the last few days and now understand how to add switches graphically under user_buttons/template_main/template_main.ui (see attached photo).However, I don't know how to link the light switch to the output of my Mesa 7i76e, for example. I tried to implement net light => hm2_7i76e.0.7i76e.0.0.output-02 <= qtpyvcp.light in my postgui_hal. Unfortunately, that didn't work. What am I overlooking as a newbie? 
And in addition i´d like to have a nice looking Led right to the button. Red = off, green = on. I could not find one in QT Designer. Alternatively, the button itself could change from red to green.

Translated with DeepL.com (free version)

Thank you for taking the time to look at that.

I will clean that up.

Now that I'm using my ethercat machine daily, I'm seeing some odd issues. Sometimes on startup it will trigger error b2 on the drives rapidly. this is apparently a timing conflict with modbus. Happens every dozen start ups.

Today i had a new one. I homed that machine, and then it began triggering joint errors and limits exceeded despite being nowhere near limits. i had to reboot the computer, and then it was fine.

If the machine starts "fine", it stays fine, but there is some flakeyness with the start up sequence.

Another thing I notice is when I tune my servos perfectly in the omron (usb) software, when they start under linux they are resonating, vibrating like 1 micron in travel. I don't know if that's a linuxcnc thing, and ethercat thing, or just a stupid omron thing.

Other than these quirks though, its great and I would not switch back for anything haha.

need that jerk control......

Hello everyone,sorry for posting a year later. I had a lot going on and put my 5-axis milling machine project on hold.Yesterday I finally managed to recover the 7i95T. Since I’m definitely not the first – and won’t be the last – to flash the wrong firmware, I’ve put together a small guide describing how it worked for me.Thanks, PCW, for describing the procedure — it helped me a lot.Now I’m a bit more familiar with the Mesa cards. Nothing comes from nothing.

Best regards!   

I like the text and button hi lights. I just prefer a darker main background. Very Nice. 

You should not need ui changes for these pins to work.
There is a description on the pins on the page before this one.

Hi Rod,

I think there is a small misunderstanding about what I was trying to say. I’m not claiming that EtherCAT needs heavy tweaking to run at 1 kHz — I fully agree that with decent hardware, a 1 ms servo thread often works out of the box, and EtherCAT as a protocol is designed for that class of cycle times.

My comment was specifically aimed at the earlier “8 kHz on the host” remark. That kind of statement mixes three different layers: the drive’s internal loops (which indeed run at several kHz), the EtherCAT communication cycle, and the LinuxCNC host servo thread. Once you start talking about pushing the host loop into the few-hundred-microsecond range, things like DC setup, cycle stability, NIC behavior (EEE, IRQ coalescing, etc.) and jitter stop being details and become the main engineering problem. That was the point I wanted to make.

When I said Mesa tends to be more “KISS”, I meant it in an architectural sense, not as a value judgment. EtherCAT is a full industrial fieldbus: multi-vendor, DC, flexible topologies, designed for distributed systems — that’s a big strength. The hm2-eth approach is intentionally simpler and focused on talking to the card, with the time-critical I/O timing living in the FPGA. Different tools, different trade-offs.

I also don’t think a fully centralized-in-one-panel setup is where EtherCAT really shines. It still works perfectly fine that way, and in fact I think it’s great that many people run it like this today, because that’s exactly how the LinuxCNC + EtherCAT integration gets exercised, debugged and improved in practice. Its main advantages just show up much more in distributed architectures, with drives and I/O spread across the machine and synchronized via DC.

For context, I’m actually looking at EtherCAT for my own project because it’s a modular machine (about 2 m per module, ~16 m total), where a distributed setup makes a lot of sense. That’s exactly the kind of case where EtherCAT really shines. So my comments are not “against EtherCAT”, but about keeping the architectural layers clear and not mixing up internal drive loops with very high host loop rates.

So yes, EtherCAT at 1 kHz on LinuxCNC works fine in many setups, as you said. My concern was only about the conceptual jump to “8 kHz on the host”, which is a very different class of problem.

Hi,NWE,

That’s a fair point, and I agree: EtherCAT (and the lcec stack) has a much richer network/state model and clearly handles link loss and recovery more gracefully than hm2-eth. That kind of supervision and recovery is a real advantage of EtherCAT as an industrial fieldbus.

My earlier comment wasn’t about network robustness or error recovery, but about where the time-critical control loop lives when people start talking about very high host rates (like “8 kHz on the PC”). Those are somewhat orthogonal aspects: EtherCAT is stronger as a fieldbus and in fault handling, while the Mesa approach keeps the tight I/O timing in the FPGA and is more “KISS” on the host side. Different strengths, different trade-offs.

Thanks for the discussion, and all the best to everyone doing the hard work in the trenches.

rodw wrote:

In fact, I believe that ethercat protocol is superior to the Mesa hm2-eth protocol.
 

My experiments with the hardware support that belief. Last I tried this, I could physically unplug the network cable; hm2-eth crashes, on the other hand, ethercat lcec properly reports the affected slaves as no longer responding, I reconnect the cable and all functions promptly recover without a restart.

the fact that you get a bad spi payload is good, keep it at 32 probably

This may sound forward of me, but how long is your cable?