Another realtime delay question - Mesa card

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2 years 9 months ago #289648 by rodw
Run this and share a screen dump. It will confirm isolcpus is set
Code:
latency-histogram --nobase --sbins 100

I hve never used a 2 core machine with linuxcnc, mostly 4 core celerons J1900 and up. I kind of think the 2 cores are at the end of life  but a few people have got them going. Generally with a compiled kernel which is your next step. There was a thread recently where somebody showed how to compile the 6.6 kernel

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2 years 9 months ago #289652 by chienMouille
really? Honestly, I'm think I^m the nurdy type but this super low level stuff is a bit much still.

here is the screenshot

 

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2 years 9 months ago #289654 by rodw
Are you still getting realtime delays?
In answer to your question latency under 150000 even up to 200000  are generally OK.

You need to run the test for longer and run a few glxgears

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2 years 9 months ago #289656 by chienMouille
Ok, I'm gonna run the histogram for a while with some glxgears. I'll come back to you with the results.

In the meanwhile can we do a bit of vulgarization here?

Tell me if I get this right:
From machine to computer: The servo needs (I guess) 230V with a varied frequency to control its speed (I guess that is pulsed in some way, I really never looked into it). The servo controller supplies this to the motor, following instructions in the form of 5V DC pulses coming at high speed from the Mesa card. This timing is obviously critical, hence the dedicated mesa card. The Mesa is talking to the computer through the ethernet port. What's happening there: does the computer send straight Gcode (in binary form or something) or does it itself send pulses that are then buffered in the mesa)? What translation happens from the Gcode and where? What's the risk of a realtime delay in this communication? To miss a pulse? To miss a whole Gcode line? To crash?

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2 years 9 months ago - 2 years 9 months ago #289658 by chienMouille
So herewith is the new screenshot after a while and with 5 glxgears. So it's quite exactly 150000 right?
I still get realtime error messages.
Here is the timing in the ini file. should I change it?

Code:
[EMCMOT] EMCMOT = motmod COMM_TIMEOUT = 1.0 #BASE_PERIOD = 80000 SERVO_PERIOD = 1500000

 

Otherwise, should I compile a Kernel? I must say I like high level stuff like python coding, but words like kernel and compile together give me shivers.

Another option would be to get something like this:

www.prodimex.ch/gigabyte-brix-gb-bace-31...ace-3160-109329.html

quad core. and migrate the ssd and the ram from the one I have. Would this make sense?
Last edit: 2 years 9 months ago by chienMouille.

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2 years 9 months ago #289836 by rodw
You have not said if you are still getting real time errors. It might now be OK.

The Gigabyt N3160 is gennerally fine. I have used one for several years.
They have a realtek driver so you will probably have to install the r8i68-dkms driver.
The following user(s) said Thank You: chienMouille

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