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Hi,

Just wanted to share the control panel I've built for my VM32 CNC conversion project. The aim was to get away from a typical PC+Monitor setup and build an all-in-one control panel for LinuxCNC which can be mounted on the mill cabinet and control the mechanics through MESA board. I published the resulting models for this build in a Github repo:  github.com/belovictor/linuxcnc-control-panel
You can also find the panel build video on my YouTube: 

Best regards,
Victor Belov
 

Hi everyone,
 
I'm experiencing cumulative axis position shifts (mostly Y, some X) during helical boring operations generated by Fusion 360 Personal Use. The shift happens between passes, not during cutting. I've done extensive testing to isolate the cause and I'm stuck — hoping someone with trajectory planner experience can help.
HARDWARE:
- 3-axis mill, 1204 ballscrews
- Mesa 7i96s ethernet card
- Teknic ClearPath CPM-SDSK-2311S-RQN servos (step/dir mode)
- 75VDC PSU
- Raspberry Pi 5 running Debian Bookworm
- LinuxCNC Master (2.9)

THE PROBLEM:
When running a Fusion 360 helical bore operation (3 passes: rough, semi-finish, finish), the machine shifts position during the helical arc cutting itself. The first boring pass starts correctly, but position drifts during the operation. The shift is cumulative across passes — each subsequent pass is worse. I initially thought the shift was only happening between passes during repositioning, but after extensive testing I've confirmed it also occurs during the actual G3 helical arc execution.

WHAT I'VE RULED OUT:
1. NOT mechanical: Dial indicator shows <0.01mm backlash. Coupling and ballscrew are tight.
2. NOT motor faults: ClearPath LEDs stay green, no faults. (Note: HLFB is wired but not yet configured in HAL — this is on my to-do list.)
3. NOT lost steps during linear moves: I wrote a test program doing 20 cycles of G91 G1 Y50 F1000 / G1 Y-50 and Y returns perfectly. Zero shift.
4. NOT electrical noise / VFD: Shift occurs with VFD off, spindle off, no tool, air cutting only.
5. NOT step timing: Tested DIRSETUP/DIRHOLD at 2000, 5000, and 10000ns. 5000 was slightly better but didn't solve it.

WHAT I'VE FOUND:
The problem appears related to how the trajectory planner handles the G-code Fusion 360 Personal generates. Key factors:
A) Fusion 360 Personal Use converts ALL G0 rapids to G1 moves. This means repositioning between bore passes (retract, XY travel, approach) are G1 moves subject to G64 path blending. The machine blends through the repositioning corners instead of making exact stops.
The bore operation uses helical arcs (G3 in XY with simultaneous Z) — this is the exact pattern described in GitHub Issue #426 (Arc Blending Bug).
C) I tested ARC_BLEND tuning parameters:
ARC_BLEND_ENABLE = 1
ARC_BLEND_FALLBACK_ENABLE = 1
ARC_BLEND_OPTIMIZATION_DEPTH = 50
ARC_BLEND_GAP_CYCLES = 4
ARC_BLEND_RAMP_FREQ = 100
D) ARC_BLEND_ENABLE = 0 did NOT fix the second file either.

G-CODE STRUCTURE:
The problematic repositioning sequence between bore passes (02.ngc):
N635 G1 X-77.844 Y12.6 (exit move)
N645 Z5. (retract - G1, should be G0)
N650 Z15. (retract more - G1, should be G0)
N655 Z4. (approach - G1, should be G0)
N660 Z2. (approach to cut depth - G1)
N665 X-80.544 Y13.2 (XY reposition AT cut depth - G1, gets blended!)
N670 G3 X-81.144 Y12.6 ... (arc cutting begins)
My INI Snippet:
[EMCMOT]
EMCMOT = motmod
SERVO_PERIOD = 1000000
ARC_BLEND_ENABLE = 1
ARC_BLEND_FALLBACK_ENABLE = 1
ARC_BLEND_OPTIMIZATION_DEPTH = 50
ARC_BLEND_GAP_CYCLES = 4
ARC_BLEND_RAMP_FREQ = 100
 
[JOINT_0] (X)
MAX_VELOCITY = 50
MAX_ACCELERATION = 150
STEPGEN_MAXVEL = 62.5
STEPGEN_MAXACCEL = 250.0
DIRSETUP = 5000
DIRHOLD = 5000
STEP_SCALE = 200.100
 
[JOINT_1] (Y)
MAX_VELOCITY = 50
MAX_ACCELERATION = 150
STEPGEN_MAXVEL = 62.5
STEPGEN_MAXACCEL = 250.00
DIRSETUP = 5000
DIRHOLD = 5000
STEP_SCALE = 200.460
 
G-code preamble: G64 P0.005 Q0.005

QUESTIONS:
1. Is there a known interaction between Fusion 360 Personal's G1-only rapids and the trajectory planner's arc blending that could cause multi-millimeter position shifts?
2. Is there a recommended set of ARC_BLEND parameters for helical boring operations where G1 repositioning is mixed with G3 arcs?
3. Would modifying the linuxcnc.cps post processor to insert G61 before repositioning moves and G64 before cutting moves be the correct approach?
4. Should I be looking at something else entirely?
I can attach the G-code files if helpful. Any guidance appreciated — I've been chasing this for a while.
 
Thanks!

Marcos wrote:

@RODW,

Have you tried Ventoy?

I've tried a number of tools and the only one that has never let me down is balena etcher. It even works with raspberry pi images!

Hello everybody!
I am new to this forum, so first I want to thank everybody for all the information posted here.
I want to replace my old 32-bit computer running a 3-axis stepper cnc via a parallel port. 
What I succeeded in:

1. I bought a Raspberry Pi 4 and a Mesa 7i90 card.
2. I used my old computer with parallel port, connected to the 7i90 and programmed the 7i90_spi_svst4_8.bit firmware using mesaflash.
3. I downloaded the LinuxCNC disk image for the RPi 4 and installed it.
4. I connected the 7i90 to the Raspberry Pi (about 3 inch flat-cable, all ground lines connected). I can read the device configuration using mesaflash without problems (well after a new install of mesaflash from the git repository).

Now I want to start ``linuxcnc linuxcnc/configs/by_interface/mesa/hm2-stepper/7i90-rpi-spi.ini``. The GUI pops up and everything seems fine.
But when I press F1 to reset the estop latch nothing happens. Up to now I did not connect any drivers or switches to the 7i90.
I changed 'DEBUG = 0x7fffffff' in the ini-file and added a 'show' to the end of the ini-file. I attach the output when running the linuxcnc. I marked what happend when I pressed F1 by '******' in the text.
If you need more information (ini-file, hal-file) let me know.
Many thanks for any support, H. Hermes

masawee wrote:

but normal need use WHITOUT this expensive hat , only gpio pin out and shift level converter can use 3,3V gpio pin to out 5V and traight to driver step and dir and enable pin.
how this made if ewer newer not has understand anything code nd not understand what need doing code, understand only good all hardware how connect and build,
i have rpi4 and SD card have linuxcnc rpi4 image, working and boot ok, (whit HDMI display) but not boot whit pi hut mikro HDMI to vga cable.
how make this gpio pins can take out gpio pin to driver DM556. were can download setting hal and ini file or what need add to rpi4, normal peoples NOT can understand and write hard code to rpi, hal or ini or what possiple need doing, not know.
i just buy rpi4, paraller port BOB, cheap chinese 10$ board, encoder, rotary SW, shift level converter modules, 3,3V to 5V, all buttons, DM556 drivers, nema 23 470 OZ/3Nm motors, lot hardware but not can made code anything.

help need send to me files what need copy and paste to rpi4 linuxcnc and were folder need add. not know were and what and how.

I have not tried connecting a BOB to a Raspberry pi. I think it could work but it will not be easy. You will have to write the hal and ini files.

How will you connect BOB to the Raspberry pi? The connectors are quite different.

If you could use your BOB connected to a pc that has a parallel port that will be a lot easier. I might be able to help. Then you could use stepconf to create your configuration.

but normal need use WHITOUT this expensive hat , only gpio pin out and shift level converter can use 3,3V gpio pin to out 5V and traight to driver step and dir and enable pin.
how this made if ewer newer not has understand anything code nd not understand what need doing code, understand only good all hardware how connect and build,
i have rpi4 and SD card have linuxcnc rpi4 image, working and boot ok, (whit HDMI display) but not boot whit pi hut mikro HDMI to vga cable.
how make this gpio pins can take out gpio pin to driver DM556. were can download setting hal and ini file or what need add to rpi4, normal peoples NOT can understand and write hard code to rpi, hal or ini or what possiple need doing, not know.
i just buy rpi4, paraller port BOB, cheap chinese 10$ board, encoder, rotary SW, shift level converter modules, 3,3V to 5V, all buttons, DM556 drivers, nema 23 470 OZ/3Nm motors, lot hardware but not can made code anything.

help need send to me files what need copy and paste to rpi4 linuxcnc and were folder need add. not know were and what and how.

have anybody make rpi4 working linuxcnc, what need doing gpio pins config, this hal,demo and html not help anything what need doing, not understand what must make, ewer not has written and understand code, only test run "blink" code and working.

just buy rpi4 and encoder wheel, buttons, rotate switch, shift level converter 3,3V to 5V and stepper motor drivers DM556 and nema 23 470 OZ/ 3 Nm motors, and install rpi4 linuxcnc image to card and run image, ok, but were is config wisard gpio pins ?
config wisard has only paraller port pin config.
pnc config has only ower expensive mesa card config.
how config all pins to rpi4 gpio ???? has anybody make this and can tell step by step or send config files what need rpi4 working whit this linuxcnc rpi image.
image boot and run ok, step conf wisard no help how gpio pins setting.

what this is, not understand lot say hal need write code but not understand anything what code need write, not easy help, lot has only english plaa plaa plaa but no say how use gpio pins linuxcnc rpi4 stepper drivers pins step and dir and enable, paraller port has simple easy but why not rpi4 have same system can add pins and step/dir, number. etc, pin 17 is x axis step, pin 13 is x axis dir, were this is, or not have why not.

i just install rpi4 linuxcnc image to my rpi4 but step conf wisard not have gpio pins can config, how make this, i looking today pnc config but has only mesa card config, no working if need only gpio pins output to stepper driver board DM556. i use gpio pns and shift level converter 3.3V to 5V convert and then 5V can use output to stepper driver, but how config all gpio pins what i need use. step conf wisard not can, pnc config wisard no can its only mesa card conf. how peoples has made rpi gpio run drivers and inputs.

rpi4 boot ok linuxcnc 2.9.x whit my HDMI display but not old VGA display say only out off range 1. rpi used mini HDMI to vga cable and working good normal image raspian, but not whit linuxcnc image .

I was thinking of building a new image for the Raspberry Pi 5. It will feature 2.10 to get scurve planner and be on Trixie and use the 6.12.74 RT kernel
Is there any reason not to use our current installer framework? 
Is there anything that desperately needs changing?

It just seems to be still the best way forward and I have the template to start with.

Hi LinuxCNC community,I am running a Mesa 7C80 via SPI on a Raspberry Pi 5. Because my main axes and spindle are handled over EtherCAT, I am not using the standard StepGens.I need to drive three linear coil motors that require a standard 5V hardware PWM signal. Could I please request a custom bitfile that replaces the first three StepGens with PWM Generators?Specific Routing Request:

• TB7 (Normally StepGen 0): Replace with a PWMGen.
• TB8 (Normally StepGen 1): Replace with a PWMGen.
• TB9 (Normally StepGen 2): Replace with a PWMGen.

Ideally, I would like the primary pin on each of those terminal blocks to act as the PWM output, and the secondary pin to remain available as a standard GPIO so I can use it for the Direction signal.Thank you in advance for your time and all the support you give this community!

T3 ist das Netzteil für das Raspberry Pi. Ist das offizielle also hatte ich gehofft die Qualität ist etwas besser. Die Buskabel sind hochwertige von Lütze mit Siemens Profinet Steckern. Benutzen wir auf der Arbeit auch so.

Unter dem Metallsteg sitzen das Hauptschütz wo 3 Phasen und Neutralleiter dranhängen, ich tippe, dass das Probleme macht. Ist zwar suboptimal mit dem Metallsteg aber solange es funktioniert... Kommt eh ein Deckel drauf.

Mit dem RCD muss ich noch gucken, ich muss eh die Elektroinstallation neumachen da ich in der Werkstatt noch keinen Drehstrom habe. Hoffe wenn ich da einen extra RCD für die Maschine setze ist der Ableitstrom nicht zu hoch. Als ich so getestet habe (einfach temporär in der UV abgegriffen) hat der RCD ausgelöst aber da kamen ja noch ableitströme vom restlichen Haus dazu.

 

So sieht meine Steuerung mit EtherCat aus. Servos von Lichuan über AliExpress und StepperOnline über deren Website gekauft. Nutzen alle das cia402 Profil, lassen sich also identisch ansprechen. Einzig die vid (Vendor ID) und pid (Product ID) sind anders, müssen also in der ethercat-conf.xml angepasst werden. Man kann die Treiber meines Wissens entweder direkt am Gerät einstellen oder über die ethercat-conf.xml mit SDOs. Letzteres habe ich aber noch nicht ausprobiert. 

Als IO nutze ich Beckhoff Module (EL1018, EL1008 und EL2008 sowie Potentialverteilermodule) weil ich das besser finde als die IO Pins der Motortreiber zu nutzen. Brauche eh mehr als die Treiber bieten. 

Als LinuxCNC Rechner und EtherCat Master läuft ein Raspberry Pi5 8GB. Das größte Problem hatte ich mit EMV, EtherCat scheint deutlich anfälliger zu sein als was ich von Profinet auf der Arbeit gewöhnt bin. Deshalb habe ich im mittleren Kanal einen geerdeten Metallsteg eingesetzt, so scheinen die Probleme behoben zu sein. War leider im Platz etwas begrenzt, sonst hätte ich das Schütz -Q1 nicht direkt unter die IO-Module gepackt. 

hi, can this image use traight to gpio too, rp4b board and i made 3,3V to 5V output level converter board use traight gpio output to stepper motor drivers DM556,
and same i build optocouplr board all input opto to gpio can use safety all gpo, not used BOB card or other board, i made diy own in/out gpio to 5V convert board, hope image can use straight all step/dir, enable, signal out to gpio pin. its easy use level converter module can convert 3,3 rpi output to 5V input by stepper driver controller etc, DM556.
same i think can easy use optocoupler module all input gpio pins. 5-24V in to opto and then 3,3V safety to in rpi gpio.

I have also implemented support for MDS-B-SVJ2 Servos via ethernet. That's the first test. X/Y/Z and the spindle are ok (the video only shows X/Y). I will make some other videos within the next weeks. For a test it's connected via USB ethernet adapter to my notebook (I will move it to a raspberry PI within th next days)

Still quite some way to go .. tool changer, lubrication system, chip conveyor and so on. My Meldas M65 controller had issues with the battery 3 times in a row (and we bought them original from Mitsubishi), everytime the settings are gone we would have to drive to Mitsubishi to put the options in... I'm done with that and move the system to LinuxCNC now.