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For axample:
Aluminium extrusion profile L=1200mm (2.9 kg) vs aluminium 50x50x2 tube L=1200mm (3.6kg)

I must say that the weight comparison seems very counter intuitive.

[edit]

you are comparing aluminium extrusion profile to  50x50x2 steel tubing (8000kg/m3).

The most likely problem is that you have 'anglejog.current-scale' = '0'.

Note that the 'anglejog.scale-in' value is only sampled when 'anglejog.enable-in' is false. (See 'Notes' in the man page linked above)

You may want to have a look at the anglejog sim config :
configs/sim/axis/anglejog

 

Thanks, well spotted! I was hoping that 1/3200 microstepping would work.
Perhaps I will have to do a 1/3 reduction later. For now I think I'll try how this works.

The goal is to get linuxcnc up and running first and try to configure everything properly



The point of the 80x40 extrusion profile I certainly do not agree with as a mechanical engineer.
The 80/40 extrusion profile has a much higher stiffness compared to a normal tube. Especially compared to an aluminum tube.

For axample:
Aluminium extrusion profile L=1200mm (2.9 kg) vs aluminium 50x50x2 tube L=1200mm (3.6kg)

Comparison of Bending Resistance
ProfileDirection (axis)                                        Section Modulus (W) 

80x40 extrusion
Major axis (80 mm high) → bending about        X = 8,898,884 mm³ 
Minor axis (40 mm high) → bending about        Y = 120,303 mm³

50x50x2 mm box
Any axis (symmetric) → c = 25 mm                    X and Y = 5,912 mm³

Key Differences:

In the x-axis, the 80x40 profile has ~1500× higher section modulus (1500x stronger!) and is 20% less heavy than the 50x50x2 box.

In the y-axis, it still has ~20× higher section modulus (20x stronger!).

Agreed on the gear reduction or machining a smaller pulley. I think they make htd in 3mm pitch so you can reduce pulley size.

The goal with plasma is to accelerate as fast as possible to the desired cutting speed to minimize slag...... That's basically the entire goal..... The less time you are in-between stopping and cut speed the less slag you will have. So keep all motion components as light and strong as possible. That 80/20 t slot extrusion is heavy and weak (for the weight), use square tube instead.

Also 3d printed parts are fine for a prototype/hobby machine but you are building a machine that shoots sparks everywhere and makes things very hot. Plan for machining the parts out of AL if you want to use it in an industrial environment.

Hope that helps

A guess:

setp hal_gpio.pin-40-out-invert true

Running LinuxCNC and then running:

halcmd show all | grep invert

in a terminal window should give the the exact naming syntax

 

1 No double posting
2 most VFD's can do 0-5V or 0-10V settable, see manual
3 to invert pins on LinuxCNC it is as simple as :Should be similar for RPI, but i do not use RPI so no way of confirming from my side, give it a try.

Hello everyone,

I'm setting up a PWM-controlled spindle for my LinuxCNC machine. My analog DC motor controller requires a 0-10V input, which I'm generating with this specific PWM-to-analog converter: www.amazon.co.uk/Digital-Analog-Module-C...&smid=A2BXCFIGGD7VDT.

The PWM signal is sourced directly from a Raspberry Pi 5's GPIO, routed through our custom-designed isolator board HAT, V1.1, which you can find details about here: github.com/data124001/Isolation/wiki. We're running LinuxCNC version 2.9.1 and using the hal_gpio library.

The core issue is that this specific PWM-to-analog converter appears to invert the control signal: a 100% PWM duty cycle from the Pi (and hal_gpio) results in zero motor speed, while a 0% PWM duty cycle results in full motor speed. This means my spindle speed control is completely reversed from what's expected (higher LinuxCNC speed command = lower motor RPM).

We have confirmed that the PWM signal generated by the Raspberry Pi 5's GPIO (whether directly or via our custom isolator board) is behaving correctly in terms of duty cycle interpretation (e.g., 50% duty cycle is "half on"). However, without this specific PWM-to-analog converter in the loop, we have no meaningful 0-10V speed control for the motor controller, only basic on/off, as the raw PWM is unsuitable.

Therefore, the problem lies squarely with the inversion introduced by the Amazon PWM-to-analog converter itself when converting the standard Pi PWM.

My question is: What are the most effective and robust methods within LinuxCNC's HAL configuration to invert the hal_gpio PWM signal before it reaches this converter? I'm looking for a HAL-based software solution to achieve the correct 0-10V spindle speed control (where a higher LinuxCNC spindle.0.speed-out value corresponds to a higher analog voltage to the motor controller and thus higher motor RPM).

I will be attaching my HAL and INI files to this post to provide full context of my current setup.

Any specific HAL configurations or example code would be incredibly helpful!

Thanks in advance.

 

OK so it looks like the hardware works.

When testing you should have a halshow WATCH tab setup like this:


 


When you set b-index-enable true (yellow) with the "Set" button, it
should go false (red) when you move the encoder past the index position.

Typically, if step/dir outputs are damaged is means there may be a
grounding or EMI issue, or the step/dir outputs have accidentally
contacted a voltage outside the 0 to 5V range.

If you use shielded cable make sure the shield is terminated to the
7I96S's GND pin (and unterminated at the drive end)

I appreciate the response, I didn't even know differential existed. I am using shielded Ethernet cables from the mesa to the drivers.

For now I've solved the issue by using another step/dir output and modifying the HAL to those pins.

But it does make me worried that this has happened and may happen again making the board useless for this machine if I loose another one.

U5 = MC74ACT540DTR2G

U7 = MC74ACT541DTR2G

Digikey has these
 
You could also do a test to verify that the card is generally OK
by moving one axis to stepgen.04 (on TB2) because this STEP/DIR
channel uses a different driver chip (Stepgens 00..03 use U5,U7)

to test this you would have to edit the stepgen numbers in the hal file
or make a new configuration using stepgen.04 for say the x axis

He medido los voltios otra vez ahora me da 4,8v antes de encender linuxcnc y lo mismo cuando lo enciendo pero cuando le doy a mover cambia a zero voltios para un lado y y para el otro cambia muy poco

O si crees que es lo mismo u5 y u7 saves quien me la puede arreglar? O donde pedir los componentes 

Gracias 

slowpoke wrote:

Aciera wrote:

For jogging there is the 'anglejog' component:
linuxcnc.org/docs/stable/html/man/man9/anglejog.9.html
 
Thank you, and this is what I love about LinuxCNC, it seems that whatever somewhat custom idea you dream up LinuxCNC has the handle to make it happen. It's a tinkerer's  candy store.
 

I need a little assistance with anglejog please.
I added anglejog to the real time thread so I can see the parameters in HAL.
I was hoping to just do a little test jog from HAL before connecting coscounts and sincounts to the servos in HAL.
However both those outputs seem to have really large numbers. Please see attached.
is there anything obvious that I'm doing wrong?
   
 

So, when I insert the wire into pin 13, the signal is on “Fasle” and when I remove it, the signal is on “True”. Without connecting Z to GND

I'm doing the test again today