Problems with recent upgrade to Debian Stretch

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16 May 2019 11:11 #133959 by aaron
Hi All
I have recently tried to up from wheezy to stretch and with help from the forum have managed to get the machine moving again, but it is missing steps and one axis sounds distinctly wrong when running a job (it sounds fine when jogged).
My computer skills are minimal so please bear with me, and if I am double posting forgive me twice.

I am on the 4.9.0-8-rt-686-pae kernel ?
This comes up on the axis window: Axis 2.8.0-pre1-4726-g223a27736
According to synaptic I have 1:2.8.0~pre1.4728 installed

The machine has worked well on wheezy with these configs and computer for over a year.

I have attached hal and Ini files

Any help gratefully received
Attachments:

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16 May 2019 13:40 #133970 by PCW
My guess would be that the latency is worse on the Stretch/ Preempt-RT kernel

You can find out the kernel type/version with the command:

uname -a

in a terminal window

Do you get any real time errors?

I would run the latency test to check the new OS/Kernels latency on your hardware

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16 May 2019 17:26 #133987 by aaron
Thanks for your reply

uname -a
Linux foam 4.9.0-8-rt-686-pae #1 SMP PREEMPT RT Debian 4.9.144-3.1 (2019-02-19) i686 GNU/Linux

You are right the latency has almost doubled. How do I plug the results into the configuration files. I don't see how I can run stepconfig wizard again as I have two motors running one axis.

If the resulting speed is bad can I use a different kernel, or just buy another computer with better latency. What are my options?

Cheers

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16 May 2019 17:33 #133988 by PCW
You can increase the base thread period in your .ini file (currently 66666)
but this will likely result in lower maximum speeds

I dont think there are any better kernel options for Stretch.

Are you sure you have turned off all power saving options in your BIOS?

You might also try setting the isolcpus option in grub if you have a multicore CPU

What current PC hardware do you have?

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16 May 2019 21:30 #134010 by InMyDarkestHour
setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0

Is this correct ?

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16 May 2019 23:05 #134017 by Grotius
@Aaron,

I don't know if the step conf wizard has the option for double motor's on one axis already. But if not you can set it manually with
some help.

How do I plug the results into the configuration files. I don't see how I can run stepconfig wizard again as I have two motors running one axis.

For your ini setup a short example of double motors on one axis :

Warning: Spoiler! [ Click to expand ]


Your hal file for double motors on one axis in my case...
Warning: Spoiler! [ Click to expand ]


So if you edit the basic ini and basic hal file, it would work for you. This is just for info.
Edit your files to your reeds.

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17 May 2019 02:11 #134023 by PCW

InMyDarkestHour wrote: setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0

Is this correct ?


Yes its correct _if_ you are using the stepgen components "reset" mode where the steplength
is determined by the reset time, not the steplength setting
The following user(s) said Thank You: InMyDarkestHour

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17 May 2019 02:54 #134024 by InMyDarkestHour

PCW wrote:

InMyDarkestHour wrote: setp stepgen.0.steplen 1
setp stepgen.0.stepspace 0

Is this correct ?


Yes its correct _if_ you are using the stepgen components "reset" mode where the steplength
is determined by the reset time, not the steplength setting

@myself RFTM ;)

setp parport.0.reset-time 1500
So by the ini file the steplength would be 1500ns

And step the min stepspace would be determined by the base thread ?

Would increasing the reset time be of any value (thereby increasing step length?) ?

This is purely an academic question.

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17 May 2019 09:05 #134036 by aaron
Currently, the pc I am using is an old Dell Optiplex 755. I will look into changing settings in the bios. But in the mean time are there any cheap reasonably powerful alternatives with good latenocy for this kernel?
Thanks

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17 May 2019 14:30 #134050 by PCW
Dont know where you are located but HP Elite 8300 SFFs have good latency and
are in the 70 to 100 dollar range on Ebay including memory and hard drive or small SSD

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