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Hello there,

actually i am having a high max jitter, i tried to run linuxcnc on my raspberry pi 4 and when i run the latency test i got values of servo thread of about 88972574 and base of 50056722 like in this image drive.google.com/file/d/1Dx10cUhac0YA6R9...sK/view?usp=drivesdk, and i don't know how to solve it, is it possible?

i tired with another build and the this was the values drive.google.com/file/d/1EH_aMwVQL3exWtA...7a/view?usp=drivesdk

thanks, and sorry if i miss something

github.com/LinuxCNC/linuxcnc/blob/2.8/sr...hal_pi_gpio_demo.hal

linuxcnc.org/docs/stable/html/drivers/hal_pi_gpio.html

linuxcnc.org/docs/stable/html/drivers/hal_gpio.html

Hi everyone, I'm fairly new to this. You can say I am a noob in Linux.

We want to build a CNC machine for testing stuff. I'll be using nema 23 and 17 motors connected to TB6600 motor drivers as well as limit switches and other components down the line. This will all be connected to a raspberry pi 4 and we want to use the linuxcnc to control the motors and send gcode onto them.

I wanted to know if I would I go about the configurations on my Raspberry pi4 and the components so that the software can recognize these and give them control. i searched that i need to configure or map the GPIO pins in the HAL? any responses would be greatly appreciated. Thanks!

Last Saturday I've launched this open-source project in The Netherlands during a CNC Tech Meetup, so I opened the repository. You can find it here .



The board features:

Designed for Raspberry Pi 4 and 5 (the older version RPi 3 might also work) with SPI communication

• 3 I/O connectors:
  • each 17 pins of freely addressable inputs / outputs;
  • selectable 10 kOhm pull-down or pull-up resistor;
  • optional 5V power supply on the connector;
• 2 RS489 connectors for communication with VFD's or other peripherals (powered by Rasberry Pi);
• number of GPIO can be extended by using serial connection through the three I/O connectors (up to 64 GPIO per serial channel);
• eco-system of break-out boards designed for the HUB75HAT is under development. Currently the following boards are available:
  • BOB4STEPGEN: 4 differential stepgen drivers with ENA, DIR, PULSE outputs and ALARM input. The board also has 4 inputs for homing switches, which can be individually selected to be either NPN or PNP.
  • BOB4ENCODER: 4 differential encoders with A, B and Z (index) channels. Per channel it can be selected whether it is differential or single ended, allowing re-use of possible unused channels. This board also features connectors for serial daughter boards for expanding GPIO or attaching other sensors.

Total cost of building the HAT (excluding the Raspberry Pi, but including the 5A-75B) is around 35 Euro.

There is still some work to do in that repo, for example the board has the following issues:

• the space around the 40 pin connector of the HAT is a bit tight with the mounting points of the RPi. The solution to work with the current board is to use plastic stand-offs and cut part of these away.
• the enable signal should be inverted on the board, because the buffer Output Enable (OE) is active LOW. I rather send a HIGH signal to the board to enable it (safety).
• enable LED is not working (can also be a problem with the buffer IC, had some trouble with soldering this buffer). However, even if this LED was working, it would indicate that the board would be disabled (see previous point);
• The 3 I/O headers do not have space for shrouded headers. Instead, I chose to use colored pin headers to show the different functions of the pins;

  Raspberry Pi to drive a stepper motor, you need to connect a motor driver module such as L293D or L298N. both of these modules are suitable for 12V stepper motors. Therefore, the choice of driver module depends on you and here the L298N motor driver module has been chosen.
  L298N is a specialized driver IC, which is an H-bridge IC and differs from L293D by its increased output current and enhanced power. Its output current is 2A, the maximum current is 4A, the maximum working voltage is 50V, it can drive inductive loads, such as high-power DC motors, stepping motors, solenoid valves, etc. Especially, its input can be directly connected with the microcontroller, thus it is easily controlled by the microcontroller. When driving DC motors, it can directly control stepper motors and realize forward and reverse motor rotation, which can be realized by changing the logic level of the input.
  The above is my intercept from the information on the steppermotor website, there are many related tutorials on it.

Well, user error is the fault. Long story short, the switches were not correct hence my steps were not correct.
Got that and a few other things fixed and now my lathe is up and running! Thanks for the help!

Managed to sort the REV/FWD issue out. I think Output1 is stuck on, no matter polarity it instantly grounds my signal cable.
Changed over to use Output 4 and 5 instead, works fine now!

Next problem that has me quite stumped.
I've set my drivers to 1600 steps per revolution. They're geared 2:1(motor:screw) and for Z it uses a 5mm/rev screw.
This should equal 3200/5 = 640 steps per millimeter.
I however need to input 16000 steps to get a millimeter of movement. 
Similar on X where I need 5000 steps but should need 800.
Need to have a good long think about what could cause this.

Hola a la comunidad

He empezado un proyecto consistente en un torno CNC. De momento me estoy centrando en la estructura, la base, las patas y lo que son las guías Z del torno. Aquí tenéis mi repositorio para quien lo quiera ver: github.com/joseplluisc/torno. Tengo también fotografías. El caso es que me gustaría contactar con alguien para que me pudiera orientar LIGERAMENTE con algunos temas. No preciso que me hagan nada. Ya tengo bastante hierro comprado, el VFD, el motor de 2,2KW i algunas cosas más. Soy un entusiasta de la electrónica, arduino, raspberryPi y he hecho ya bastantes proyectos en electrónica. Soy licenciado en matemáticas e informático de profesión con 28 años de experiencia. Tengo muy claro la profundidad del proyecto, pero siempre viene bien alguna orientación puntual. Agradecería que alguien pudiera contestarme a algunas preguntas prácticas.

Mi agradecimiento por adelantado a todos y un saludo cordial
José Luis    

Stubborness pays off apparently. 
Managed to flash the mesa card using:
mesaflash --device 7i96 --addr 10.10.10.10 --write 7i96d_1pwm.bit
mesaflash --device 7i96 --addr 10.10.10.10 --reload

and then adding:
setp hm2_7i96.0.pwmgen.pwm_frequency 10000
setp   hm2_7i96.0.pwmgen.00.scale 1600 #max rpm
net spindle-output hm2_7i96.0.pwmgen.00.value
net spindle-enable hm2_7i96.0.pwmgen.00.enable
setp hm2_7i96.0.pwmgen.00.out0.invert_output true

Ontop of this I have a PWM to 0-10V module so step- of the pwmgen goes to the pwm module and then on to the VFD.
In the main hal file(if I remember correctly) I changed to 1 pwm gen and 4 stepgens.
I suspect this is the same result as selecting 7i96S and renaming it afterwards
Things seem to work now except VFD won't go into "gear", speed changes according to 'M3 Sxxx' commands if I manually ground FWD or REV on the vfd.

I can tell on the mesa card that it is switching output2 and 3 as it should, but something about my wiring must be off.
VFD ground is the same as the Mesa cards ground to make sure they're on the same level.
I'm guessing that maybe the lack of voltage difference could cause issues with SSR's or maybe I need a pullup resistor if the levels are possibly floating around a bit?


Will give 2.9.1 a try in the future! 

Use the raspberry pi image for 2.9.1 on the downloads page. There is nothing experimental about it. It uses the official Raspberry pi kernel and Debian Bookworm and linuxcnc 2.9.1

2.9.1 is in the process of being released so some parts of the website still need updating but the downloads page is solid. the image follow on from an installer I built which has been available on the forum here for a while.

If you cannot get mesact to work, what I would do is
run pncconf but select 7I96S instead of 7I96
This will allow you to setup the spindle PWM

To get a working configuration for a 7I96, you now just need to
change the card name in the ini file from 7i96s to 7i96

Yep, should've realized that way earlier, the clash of IP addresses.
Been trying to sort this out for the last few hours...

Incase the raspberry was outdated I tried running sudo apt-get update and sudo apt-get upgrade but only gave me some "see apt-secure(8) manpage" error.
Whole bunch of googling to find that "apt-get update --allow-releaseinfo-change" solved it. Could finally install all updates.

A whole lot more googling to find out how to set the ip properly.
Added the lines 'interface eth0' and 'static ip_address=10.10.10.11/8' after using 'sudo nano /etc/dhcpcd.conf'.
Now I could finally ping the mesa card and get a good response!
I've tried setting this before in the GUI but didn't seem to work, granted I may have done something wrong without realizing.

So after that I've struggled for quite a while trying to install 'Mesa configuration tool 2', took me a loooong while to see that it doesn't work on raspian 10. Still not sure how to get around that.
Trying to understand how this works. Raspian10(Buster) is based on Debian10 and is basically the operating system?
LinuxCNC gets installed with the OS and is somehow bound to it and not just a "regular program"?
The image I downloaded from linuxcnc.org/docs/stable/html/getting-st...etting-linuxcnc.html is raspian10 hence doesn't work with the MCT2. 
linuxcnc.org/downloads/ links to LinuxCNC 2.9.1 based on 'raspian 12' so that could work but then requires some experimental kernel(which I have no idea what it is)?


Downloaded the zip of configs from mesa's website hoping maybe I can use that and not need the MCT2, that's my current step, trying to flash the one with a pwm output... To be continued.

ckuecker wrote:

I've very impressed with the latency numbers - an order of magnitude better than what I was getting before.
 

Thanks. Good feedback. Getting a decent 64 bit kernel onto the pi makes quite a difference!
A lot of other installs are only 32 bit.

Found that suggestion. Got everything running now.
I've very impressed with the latency numbers - an order of magnitude better than what I was getting before.
Thanks for the help!

try running sudo menu-config
That lets you set locale and wifi