bladekel wrote:

I am using a Raspberry Pi 5 with the LinuxCNC Debian Bookworm image.
I have configured the system to communicate over SPI.
I can move all axes, but when I run a G-code file, I experience a drift in all axes.

To troubleshoot the issue, I wrote a simple G-code program that only moves the X-axis: it moves 10 cm in the positive direction and then 10 cm in the negative direction.
I set this program to run continuously in a loop. In every cycle, a small shift occurs in the positive direction.
After 20 repetitions, I observed that this drift reached approximately 5 mm.
The start and end points of the program shift slightly in the positive direction with each iteration.
I have also tested it at very low speeds, but the result remains the same.

I am certain there is no mechanical backlash or electrical interference/noise.

I am attaching my configuration files. What do you think could be causing this?
 

For those who might encounter this problem, just like me;

This problem is caused by the dir_delay. 
Solved by increasing the dir_delay value.

I am using a Raspberry Pi 5 with the LinuxCNC Debian Bookworm image.
I have configured the system to communicate over SPI.
I can move all axes, but when I run a G-code file, I experience a drift in all axes.

To troubleshoot the issue, I wrote a simple G-code program that only moves the X-axis: it moves 10 cm in the positive direction and then 10 cm in the negative direction.
I set this program to run continuously in a loop. In every cycle, a small shift occurs in the positive direction.
After 20 repetitions, I observed that this drift reached approximately 5 mm.
The start and end points of the program shift slightly in the positive direction with each iteration.
I have also tested it at very low speeds, but the result remains the same.

I am certain there is no mechanical backlash or electrical interference/noise.

I am attaching my configuration files. What do you think could be causing this?

I tried on a Raspberry Pi 4 with image "image_2026-01-21-raspios-lcnc-2.9.8-trixie-arm64"
and on a Laptop with image "linuxcnc_2.9.8-amd64.hybrid"
and unfortunately i get the same results on both, with the simplest configs i can do, even in the test/tune tab in pnc wizard it acts the same way, Sorry guys i may be missing something really basic here, do you think it might be the firmware?

config name "GG" made on the laptop

Files attached

Yeah that’s the one

I was trying to load gcode file for small engraving of size 200x150mm, gcode file size is 243MB. I tried qtdragon_HD and Axis GUI both crashes while loading the file. Even I tried disbling preview by adding (AXIS,hide) at start of GCODE. But didnt helped. Using Raspberry PI 5, 4GB RAM version.

Untested

 

 

i think NOT need this HAT, i think can build own "hat" mean connect to gpio pins shift level converter tx108 chip module, input is 3,3V and this module convert output to 5V and this 5V signal can wired to stepper driver board DM556 etc, step pin and dir pin and enable pin. but problem have how i setting rpi4 linuxcnc all gpio pins ? rpi4 and has installed linuxcnc but if looking have only config wisard and this can only setting paraller port pins, and pnconfig tool has only how setting mesa card pins, i not understand how can setting rpi4 gpio pins all step, dir, enable and all input pins home, e-stop, limits, probe, etc pendant encoder, rotary SW, axis select, scale select. i have installled linuxcnc to rpi4 and software/image working ok, but how setting gpio pins ?

Hello forum,
I have 6 x 1KW Lichuan LC20 drives and have been trying to get them to work with Raspberry Pi 4B 4GB and LinuxCNC for about 9 months.  I realised I don't have the technical knowhow to make this work.  Using this forum, youtube and Grok, I was able to get close, getting the Raspberry Pi to work as a master and I even got all 6 drives to work as slaves, but trying to get them in to OP mode proved impossible.  On one occasion, when I unplugged 5 of the 6 drives, I managed to get it to go into OP mode but have not been able to replicate it since.  And I have never been able to understand how to get them to turn using LinuxCNC, that baffles me a bit so I have never actually seen the motors work ever.
I am open to buying hardware that kinda works out of the box but I have no idea what that is.  
Can anybody on this forum work with me over time to help me to get these things to work with LinuxCNC, or even Mach???  I can't return them, and after spending $2K on them, I can't afford to buy something a little more 'out of the box'.
Any assistance would be greatly appreciated.
Andrew.
 

Is it this?  github.com/cakeslob/RRW_LAB
google does not find it but duckduckgo shows it first

Hi, I’m new to linuxcnc and I am trying to get the rrw lab board to work. I’m trying to use the SPI sd card firmware with an STM32 Blackpill. The blackpill led is flashing, but there’s no connection. I can’t seem to find anything online about setting up SPI with a pi5. Any help would be appreciated. 
Thanks.

Hi all. I've been playing with a design for a board that will allow me to read arc voltage with a Raspberry Pi. I think I've got something that will plausibly work. I'd appreciate a review of the attached schematic because circuit design is not my core competency.

Here's a quick tour:
1. Inputs are expected to be connected to the arc volt port of a blowback-start plasma power supply. 
2. Input voltage is limited to 250V by a TVS diode
3. Voltage is divided 50:1
4. RCRC filter limits frequency to 14Hz
5. Raspberry Pi reads divided voltage via ADC

Thanks!
 

Hello All,

New to the forum and first of all would like to thank you for the valuable information you guys post, it has helped so much me moving ahead with my build. id appreciate your help with my issue where it cannot activate the thc even when all the settings (that i know of) have been properly adjusted. first my setup:
-LinuxCNC QTPlasmac table
-Rpi5 with image LinuxCNC 2.9.8 Raspberry Pi 4/5 OS based on Debian Trixie
-Mesa 7176s over ethernet
-THCAD2 + 3M resistor array enclosed near the plasma source, F+/F- routed to mesaboard encoder input A with shielded microphone cable grounded at control side, also used a more simple twisted pair for testing.
-Used Pnconf for setting thcad2 trimming and ratio
Tested for correct voltage measuring for example, hooked a power supply from 39 to 56 volts and Main screen voltage readings coincide very accurately to multimeter reading.
-Flaring 65 plasma source with no cnc interface. (HF piercing) voltage probing connected to torch (-) and clamp (+) leads.
-For testing im using a straight line of 100mm at full speed so thc is not affected by speed reduction  (tested from 400 to 1800 mm/min)
-THC is enabled
-Mode 0 is used so arc ok is derived from voltage readings
-setup plasmac.arc_lost_delay =.3 as was having some issues for getting it to start cutting due to initial spike/valley.

I took the follwing HALSCOPE trace where:

 

1)torch on triggers,
2)probe voltage goes to 260 for piercing, then falls, then recovers to around 94v
3)Arc OK signal goes to true
4)Pierce delay elapses
5)Movement starts
6)THC active never goes up and of course  no correction

as Far as I can see voltage is "stable" once cut starts and there is no variation that could lead to deactivation as the tresholds are LOW=39 HIGH 990 (for testing purposes), samples 10 and threshold voltage 10.

has anyone had this issue or any lead on what to look at?

 
Hi all,

I am developing a 4-axis foam cutter using a Bigtreetech Octopus Pro V1.0.1 F429 connected to a Raspberry PI5 via SPI.
I have amended the Config.txt file, the .hal and .ini, and named the axis as X, Y, A and U.

What happens is the following:
1- X and Y axis work fine.
2- If I try to move the A-axis, then both A and U move.
3- If I try to move just the U axis, then nothing happens.

What am I missing?

I have attached the board pin mapping, the Config.txt and my .hal and .ini files, which were modified from those in the remora "ConfigSamples"  directory.

Cheers
Pier