Isel Fb2 and Isel CPM 3020 retrofit, works gmoccapy with laptop and Mesa 7i92

Hello LinuxCNCguys,
some time ago i purchased two older Isel milling machines/routers, an Isel cpm 3020 and an Isel FB2.
Both machines no longer run with the original controls, extensively tested with Isel Remote software.
For both machines i bought new stepper controllers leadshine M542 (FB2)and TB6600 (cpm 3020) , transformers etc.
I would like to use LinuxCNC / gmoccapy with 2 laptops in combination with the 7i92 Mesa card.
Has anyone run this combination, does it work perfectly?
If I have understood correctly, there is no real-time problem of latencies, etc when i use such a Mesa card.
Tested 5 computers with latencytest, only one of them is conditionally suitable.
Therefore, I now favor the solution with the 7i92 cards, it is more compact than desktop PCs.
Who provides the 7i92 cards in Germany at an acceptable price?

Best regards
Klaus

You would be incorrect to say there is no real-time problems when using Mesa cards. Real-time latencies are still important, it is just that the tolerances are greater.
When you are software stepping you have to meet the latency requirements of a very fast base-thread, that is running 20-50 times faster than the servo-thread. When you switch to Mesa cards you usually remove the need for a base-thread so the latency requirement is generally about 20 times looser. With those easier goals to meet most newer desktop hardware isn't a problem. But the power saving features of laptops still are, and if you can disable them on your laptop, you may run the real risk of overheating and damaging your laptop. (So yes laptops still are not recommended for Linuxcnc.)

Hello Todd,
thank you very much for your fast answer and helpful explanation.
There were some aspects that were not really clear to me. According to your statement it is the much better way to equip my desktop PCs with 5i25/6i25 or is the 7i92 ok?
If i am right, the 5i25/6i25 should be the faster/better cards, or?
The Mesa hardware isn't available here in Germany, the next shop to me is a portugese one.
I need a good, functional solution for my two machines, if possible with only one time order.
Maybe you have a good suggestion for me......

Best regards
Klaus

I only have experience using the 5i25. It is my understanding that for the typical system there is no practical difference in performance between those cards when used with the normal 1kHz servo-thread speed. I believe that the only time the Ethernet cards may be at a real performance disadvantage would be for a high performance system that requires a much faster servo thread speed than normal. In such a system I'd question if Linuxcnc is a very good choice for the control to start with.

Perhaps i should go a level down and give a new motherboard (AtomD525 from the list) a try.
For my relative small machines and only hobby use, it could be a solution.
It is a very time consuming process to find the right hardware.
What do you think?

Best regards
Klaus

Actually its very easy to find working hardware, almost any desktop PC will work
I would avoid Atoms like the D525 since they are rather ancient now and painfully slow

For small fanless systems , motherboards based on the J1800,J1900s are good as are newer
MBs using the J3355/J3455, But you don't need a new PC either, almost any older (say less than 7 years)
Desktop PC will work also.

Laptops will often work OK with Mesa Ethernet cards, but I would not suggest them for serious work
because of the reasons Todd mentioned, For example I can run Ethernet cards for days with my old Dell
E6420 _but_ it will fail instantly if you switch from mains to battery power or vice versa or adjust the
backlight brightness...

Hello PCW,

Actually i run the latency test on my MSI FM2-A55M-P33 with an APU 4000.
I disabled all the power saving stuff in the Bios, only the lpt, usb, and Apu graphics card is enabled.
Servo thread (1ms) Max Jitter is 1748100 (ns), i think this is one of the hardware examples that never can really used for linuxcnc.
Before i disabled a lot in the bios the max jitter was nearly as twice.

Second Pc i tested today was my old and slow Atom D525MW
Max jitter 50000, without any setting changes in the bios.

I orderd now online two new Atom D525MW bords for 60 bucks.
This bords are only use to run the Isels with linuxcnc, no internet, no music, no Cad, no Cam.
For the other stuff I use one of my notebooks that can't be used for linuxcnc.

Waiting for the postman................

Best regards
Klaus

lHello Andy,
this shop is in fact in Austria, not in Germany. ; -)
At first i test my two new D525 mainboards with LinuxCnc and the lpt port, perhaps it works well for me.
If not i have now a good shop, thank you very much for your help.

Best regards
Klaus