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Thanks to all
Final working version attached including debounce mods suggested because I hate googling for a fix that ends 'thank you' but keeps the fix secret.
Quite what is different I'm not sure but it works before you home stuff which is what I wanted.
Now I can get on with making the Pendant actually move things rather than move and then jump back to the start position
but that would be another thread I guess.
 

Yes - with that encoder & index signal LCNC will adjust feed while threading to compensate for spindle speed variations.

Tutorial 21



JT

It’s a gear driven lathe and I just don’t want to deal with variable speed , and frying the motor controller etc . Already destroyed a mini lathe motor control board lol. I had made an encoder for the mini with two wheels and two optical sensors. One had like 60 slits and the other had 1 so I under stand that .

For me just turning the spindle on manual and hitting cycle start Is fine for the needs.

I wasn’t sure if I would be able todo threading and Linux CNC would just adjust the feed to compensate for the spindle load etc .

Running "sudo apt update && sudo apt install linuxcnc" gives an error.

I blacklisted the Ethernet port.

Debian has no internet connection.

BTW, the system is a dual boot of Ubuntu 24.04 (my preferred OS) and Debian (for LinuxCNC)

I also unplugged the front audio and USB ports that I do not use.

(The back of the PC has a plethora of ports)

However, now the BIOS complains every boot

Whatever, I'll just press f1 every time I boot up to clear the error.

I'm Japanese and I'm posting using Google Translate. Please forgive me if the text is difficult to read.

In the past, I consulted with LinuxCNC2.8.2 about the phenomenon where the HOME_OFFSET operation starts at full speed for a short time when the homing operation starts. The servo amplifier is torque controlled and uses PID control. The servo amplifier is connected to the servo amplifier using an analog output module via EtherCAT. At that time, I was only connecting the JOINT and Encoder Index-enable in the HAL file, but I was advised to connect it to the PID Index-enable, and the problem was solved.

This time, I am using LinuxCNC2.9,3 to create a machine with a similar configuration, and the homing operation starts at full speed for a short time when the HOME_OFFSET operation starts. In the HAL file, Index-enable is connected to JOINT, PID, and Endoder. And the PID module of this version of LinuxCNC has a pin like the AT-PID version used in between. And there is no AT-PID. I remember that Index-enable didn't work well with the previous version of AT-PID. At the time I thought it couldn't be helped since it was for servo adjustment. Is it possible to fix the behavior when entering this HOME-OFFSET? I've looked through various manuals, but I haven't found anything. Is there some information I don't know? Please let me know.

Thank you.

I managed to lower the latency to about 14000ns max jitter by disabling hardware.

I also set the CPU governor to performance.

I will try to disable more hardware to further reduce latency.

Unfortunately, I am unable to modify and BIOS settings because this is an old scrap computer from my high school.
I tried to get the IT person to change the password, but the BIOS login window is broken

I'm trying to create custom GUI by pyqt5.
Is it possible to detect if pause is caused by M0 ?
I catch the program-paused-changed signal and than control the current_line of gcode_display.
it works if the machine paused after a move.
but if the machine couldnt started to move, the current_line didnt show the M0 line....

Thank guys, I'm starting to get a few of the blanks filled in. I now have a few more questions:

I read this (quickly)... linuxcnc.org/docs/html/lathe/lathe-user.html
I also watched this video on G76 thread cutting...

Links to other applicable documentation or instructional videos (specific to LinuxCNC lathe operation are welcome.

Now the follow-up questions:
1)  I don't see a problem using the G76 method in the video above except, I'm a hobby guy so it can be months between thread cutting sessions so with my present memory I would pretty much have to watch that video to refamiliarize myself with the various parameters before I could setup for a thread cut. Is there any sort of thread cutting wizard like GUI thing associated with Axis that simply lets you select the thread type for example 3/8-16, starting here, and ending there that then figures out the arguments required for G76?

2) Presently I have a derivative of the Clough42 ELS on my lathe and it uses a Omron 600 pulse/rev quadrature encoder. Assuming I use a MESA 7i96s to get that quadrature encoder signal into LinuxCNC, will the 600 pulse/rev encoder be fine (ie. not overwhelm Linux with too many pulses if operating at say 2000RPM)?

3) Looks like I will need a one pulse per rev sensor on the spindle correct? The Omron encoder I'm using has a Z output, so I will use that I guess.

4) Regarding the 7i96S, eventually I would like to use one or possibly two MPG style encoders to replicate the hand wheels for X and Z, it seems like I will have enough unused pins on the 7i96S, not sure if those inputs can be used for the MPG inputs and what would be involved in decoding the MPG inputs, possibly some logic in the HAL file? 

5) Not sure if I should get a 7i73 for the MPG(s), prefer to keep the hardware to a minimum if I can get away without the 7i73, comments?

6) Regarding X-axis servo. I measured with a peak torque sensor the required torque to do an aggressive cut with a dull HSS tool and peak torque was only 0.5Nm so I'm leaning towards a fairly small servo in the 1Nm range. Do you think this is too small?

7) Last question where can I find appropriate install LinuxCNC install file? I want to see if I can get it running on my RaspberryPi

Much appreciated

 

How does LinuxCNC determine the output of Spindle ON?

I tried the included wizard (stepconf).

The system works now.

Thank you tommylight!

However, I have pin 1 configured as "Spindle ON", but the output on the pin does not change.

What do I do now?

routerman22 wrote:

Hi, im wondering how to add index homing signals to the pncconf so i can do index homing. I cant seem to find the option to add the signal to the right io i put on the mesa 7i96s in pncconf.

I have 4 inputs. Index pulse x,y,y1,z axis. Can see the status. But dont seem to find the actual io option in needs to be to be recognized by pncconf as an index signal. What am i missing? 
if it needs to be a "full on" encoder in the 7i96s config... it only has 1 of those.

thank you,
routerman22
 

Hi Routerman,
Just in case you see this, since I just pulled the trigger on some Mesa cards (maybe not the correct ones...), did you ever get this to work?

I have Delta B2s so one step down from yours, but for index pulse, I think they work exactly the same.

Actually, and I don't want to get your hopes or those of anyone else reading this in the future, the B3 may be able to home internally to its index pulse... I a, pretty sure the A series can, but I feel like there's a chance that it's one of the things the B3 can do over B2. So, a signal would be sent from the controller to the servo drive and the drive would take over homing and it would report back once done.

[EDIT]
Homing To The Index/Z Pulse of Delta Servos - and Important Differences Between A and B series!

I am new at all this so could be wrong, but just had a look at the B3 manual and I am almost certain they can home "internally", meaning the servo drive handles the homing. Which might save the Mesa from the noise and speed issues Peter talked about earlier in this thread. So, it would work like this: The Mesa would send a signal to the servo drive to start homing and the drive would be configured to go look for the limit switch and then from there go in either direction to its index pulse whereafter it would send a signal to the Mesa, that homing was complete.
I think you can set up offsets, too - so, hit the index, then go to an offset, then signal Mesa. 
Sounds like a cleaner or at least potential alternative way to do this? 

Sadly, I don't have B3s but the "lowly" B2s which can't do this... 

I would assume the A-series, both A2 and A3 can do it as the A series are above the B series, but please look into that yourself if you are in the market for these and need this feature. 

What's the odds of getting a Module not listed working? The one in question I am looking for is not listed in the Github

EL2088 - 8 Negative Outputs | Supported
EL2889 - 16 Negative Outputs | Not Supported
EL2809 - 16 Positive Outputs | Supported

Will it be possible to get this working or does it have no drivers?

I've changed it so an internal MDI button resets the mode but external MDI should not.

JT