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Long story short.

The current machine is really not suitable for the most recent version.
Maybe if you elaborate on the issues we maybe able to provide a solution.
Usually if the machine is operating fine and doing the job without any issues there is no real need to upgrade.
There are many machines out there still running early versions of Linuxcnc without any issues.

if my math is right and I am reading ferror right, I am running 36000mm/m which works out to 600mm/s and an ferror of 5 (well 4.94ish, but close enough).

5/600 = .008333333 But I am running my loop at 500000 if I have configured things right so 2 round trips should be .001ish... makes me think that something else is up in that lag....

Does EtherCat time code movements so that multiple axis would all move at the right time to each other and be at the right place regardless of what LinuxCNC sees back as the time delay?

Thanks

Hi everyone,

I’ve read through a lot of forum threads and would like a sanity-check before I start converting a large manual lathe (≈ 7 m between centres, three controlled axes: X, Z and spindle) to CNC.

Outline: IPC running LinuxCNC  →  Beckhoff EK1100 EtherCAT coupler.

1) Spindle (big induction motor that must stay)
   • Ideal: EtherCAT-ready VFD.  
   • Fallback: keep the old VFD and drive it with ±10 V from an EL413x analogue-out.  
   • Right now I only need the spindle to reach the commanded RPM.  
     Do I really need extra feedback (index pulse or full encoder), or is open-loop ±10 V enough for a first-cut retrofit?
     I can add an EL5101 / EL5042 later if it saves headaches.

2) Linear axes (X, Z)
   • Replace the old drives with EtherCAT servo drives; current & velocity stay inside the drives, LinuxCNC closes the position loop.  
   • New linear scales will be fitted. Where should their signals go?
       – straight into the servo drives, or  
       – through a Beckhoff encoder terminal (EL50xx) so LinuxCNC sees raw position, or maybe both.  
   • I’m after whatever gives the most reliable closed loop without over-complicating wiring.

3) Limit switches
   • Where do people usually land these in an EtherCAT setup?  
       – dedicated digital-input terminal (EL1004 / EL1008),  
       – directly into the drive I/O and pass the state via PDOs,  
       – or something else?

4) Still unsure about
   • Pitfalls when driving an older VFD from a Beckhoff analogue-out terminal.  
   • Best practice for scale feedback on a long machine: drive only, EL50xx only, or split to both.  
   • EtherCAT servo brands that work well for retrofits (good low-speed torque, reasonable cost, easy integration).  
   • Cleanest way to wire limit switches in an EtherCAT chain.

Thanks a lot for reading. I’m grateful for any advice, success stories or warnings you can share!

Kind regards,
vformi

Hello, we have a machine with a rotary axis, in some corners the cutter does not reach the corner completely and makes a rapid movement on the rotary axis. I tried to reduce the error with G64 but lowering the P value makes it worse.

Machine is running analog servos, old yellow cap fanuc.

The error is consistent int the same place.
Attached a pic.

Thanks
 

Things I noticed in stable version .


Would it be possible to add a confirmation dialog box prompting the user before initiating another homing cycle .

When I run the program and want to pause it midway through the G-code execution to clean the machine from chips, it doesn't allow me to manually move the axis.
I believe the program should allow pausing, during which I should be able to manually move or return the axis. When I choose to resume the program, the machine should automatically return to the position it was in before the pause and continue execution from that point.
Also, if I stop the spindle and start it again, the speed is much lower than before.

When you're in the G-code editor, it's possible to start the program execution, but if you exit the editor, the program stops .

1. download Ubuntu 10.04 with LinuxCNC from here
www.linuxcnc.org/iso/ubuntu-10.04-linuxcnc3-i386.iso
2. write it to USB drive, google howto with Rufus
3. boot the PC from that USB
4. click on "try Ubuntu"
5. open a file folder, on the left find the internal HDD and click on it, on the right find /home/whatever_user_name_was_on_it/EMC2/configs
6. copy that config folder to another USB drive or a phone or external HDD
7. open that configs folder on the internal HDD, open the config inside, right click on the file with .ini extension, choose "open with" and type emc2, press enter
8. does the machine run?
If all is OK, remove the other USB or phone or external HDD, and proceed to install Ubuntu.
After restarting use the other USB or phone or external HDD and copy the configs folder where it was, start it as in point 7, or use the CNC menu and click on "create desktop shortcut" after you choose your config in the config picker.

Alright, it seems to running ok now and the tuning worked exactly how you described.
FF1 is just right at 1 and the p ended up about 5x what it was before.
Thank you

Try another network cable, kinked or nicked or stepped on cables can cause issues. Also some cheap cables will cause a lot of headaches, sometimes even not so cheap ones as i had a brand new never used cable that would absolutely not connect to Mesa. I did cut it into many tiny pieces Over 30 of the same brand worked fine.

Pinned for easy finding.
Thank you.

Ok,I will give it another shot.
I appreciate the help.

Set ferror and min ferror to 5 or so and then tune FF1 then P.

Note that if previous PWM scale was 10 (so the output would be scaled in volts)
changing it to ~50 makes the P term need to be 5 times higher for the same effect

For tuning, use halscope and plot  joint.n.ferror and joint.n-vel-cmd
if FF1 is too low, the following error during a constant speed jog
will be in the same direction as the velocity, if FF1 is too high, the
following error will be in the opposite direction of the velocity.

For P, I would just increase until you get oscillations, then back off about 50%

 

4GB ram would be be better.

Is 800MHz the fastest RAM the system can use?

If I set output_scale to 52, I immediately get following errors even with a ferror of .5.
The motor wants to drift.
I had it working, but not great with the output_scale at 10.


[JOINT_1]
TYPE = LINEAR
HOME = 0.0
FERROR = 0.5
MIN_FERROR = 0.05
MAX_VELOCITY = 5
MAX_ACCELERATION = 10.0
P = 0.1
I = 0
D = 0
FF0 = 0
FF1 = 1
FF2 = 0
BIAS = 0
DEADBAND = 0.003
MAX_OUTPUT = 0
ENCODER_SCALE = 960
OUTPUT_SCALE = -52.35
MIN_LIMIT = -3.0
MAX_LIMIT = 300.0
HOME_OFFSET = 0.0
HOME_SEQUENCE = 3

Older hardware generally needs an oldish OS.

An OS 10 years younger than the hardware seems to be a good rule of thumb.

www.linuxcnc.org/iso/ubuntu-10.04-linuxcnc3-i386.iso

www.linuxcnc.org/iso/linuxcnc-2.7.14-wheezy.iso

That PC sounds like E-waste.

Make sure RAM is dual-channel.

Just a buy new (possibly used) a PC with ethernet.

Are there PS/2 port(s)?

PS/2 keyboards are still good, arguably better than USB.

Did you know that laptops touchpads, even modern ones, are usually PS/2?