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Tutorial 19



JT

vidgabor@gmail.com wrote:

No. It's an 3 axis mini milling machine, with three steppers. I use step-dir interfaces.
 

Hi This email address is being protected from spambots. You need JavaScript enabled to view it.,

Have you managed to get it to work, please? I am asking because I am thinking of trying out the same set up. I have a Raspberry Pi 4B with 8 GB and real-time kernel. I have not bought a MESA 7I96S yet. But I am planning too.

Thank you and best regards,

...behai.

Yes, I was in a rush and was focusing more on the duty cycle. According to the manual of my driver, EN is 5V and Step and Dir will be pulled to ground.
 

Aciera post=313997 userid=25994Hm, as I understand it, this does _not_ give us multi thread gcode execution as that would require multiple parallel motion planners in the same linuxcnc instance. A single instance of linuxcnc cannot interpolate more than one tool path at the same time.

I could be wrong, but given the current API that linuxcnc is written on top of, this would likely require very deep work into the core of linuxcnc. AFAICT there are no tools in the API that can synchronize the threads for instance. Also the code appears to be heavily written for serial execution. What would probably need to happen otomh is that the api would need a way to have each thread run independently with a centrally controlled memory management cache to synchronize the various threads. so you would have a trajectory planner " all required code to execute motion" for each new instance of a aixs and have it run in it's own thread and then a central trajectory planner would keep the various thread in sync. 

at that point, it would probably make sense to port to a mulithreaded api that has c and c++ tools for this kind of work. Texias Instruments RTOS for there microcontrollers has this kind of capabiliy. Any newer x86 can do this easily if it is multicore. I am not super familiar with the ROTS version of the linux kernel that just sa release. But yes a multithreaded pi would be required bare minimum.

tool size was different until after the G43 H2 line which prompts for inserting tool 2.

That command does NOT prompt for 'inserting tool 2', that command activates TLO with offset values defined in the tool table for tool #2.

If you are not using TLO in linuxcnc anyway then I would recommend setting freecad up so it does not output GCODE that activates TLO. This way there are no surprises whatever offset values you have in your tooltable.

Why did the behaviour change?

Probably not the answer you want but most likely due to operator error.

Why are you getting -4V on the scope?
Are the probes reversed?

I removed the level shifter and connected the Tang directly to the Break out Board. Good news, it works. Then I measured at the drives and I get a nice 50% duty cycle. However, the motors still stall. And depending on where I stop, the Tang is sending Step Signals even without any movement. The motor just make sound.

 

 

Understand. I use freecad to generate the gcode from 3d models. The gcode header seems to be the same. I compared a file that was causing the issue with one from 2 years ago. Only the date and tool size was different until after the G43 H2 line which prompts for inserting tool 2.
This is routine as I always create a different path job for each tool so they are always tool 2 ( 1 being the default tool).
Why did the behaviour change?

Thanks @aciera
It works, so easy. Thanks again! I am also adding a new drilling video.

The INI file has not changed in the last year. Why had this not been a problem before? I do try to keep linuxcnc up to date, so an update may have triggered it.

There is no need to change the ini file to get different behavior like this.
TLO can be activated/deactivated through Gcode (G43/G49)
Tooloffsets can be changed through Gcode (G10 L1)


Sounds like you are missing some fundamental concepts of CNC control. Without a sound understanding of Gcode you are bound to get affected by all kinds of pitfalls.
linuxcnc.org/docs/html/gcode/g-code.html

@ C0bra
In this forum the personal message is deactivated.
Please send me an email to This email address is being protected from spambots. You need JavaScript enabled to view it. an i will send you the informations. 

 
 
 

This are the screenshots when I try to install r8168-dkms.I did not delete the first installation at the start of the post
           

Similar issue. Home made router with manual tool change, linuxcnc newbie. machine has been working successfully for 2 years.
About a month ago, the tool started cutting deeper than it should. Initially blamed a mechanical problem and performed many tests.
Today I discovered TLO (as I mentioned, a CNC newbie) and found the -1mm offset was in the tool.tbl file. Had ignored this file up to this point.


The INI file has not changed in the last year. Why had this not been a problem before? I do try to keep linuxcnc up to date, so an update may have triggered it.

Thank you, I read that severat times, but didn't pick up on the significance. Cut and paste examples... After reading your answer, I found it spelt out in the spindle man page. Sigh.

spindle.N.spindle-rpm float out

Current spindle speed in RPM.+ve = forward, -ve = reverse. Uses the encoder input if available. If not, uses a simulated encoder speed.