First go with Linux CNC, which Ethernet board?

[RB211]

So I'm putting together a purpose built Taig lathe for making security pins for lock picking hobby. Z and X will be small direct drive steppers, the spindle will be a 3 phase motor driven by a VFD. I'll need to order two cheap step/dir stepper drivers.
So I need an Ethernet breakout board that supports 0-10v DC out for spindle speed, relay outputs for spindle direction and aux functions. I assume they all have metric butt load of inputs.
I've only used an Acorn before.

[RB211]

Mesa is sold out with a chip shortage, no 7i76E's to be had...

[Dan Dubeau]

Any reason you're not going with an acorn again? If it were me I'd try and keep all my machines running on the same hardware/software if I could, in case of breakdowns, or troubleshooting problems come up. I don't know anything about converted machines but would like to build a CNC wood router and separate plasma table in the near future. Not criticizing your choice just thinking that was the way I was planning on tackling the problem. I was also considering using an acorn, and was wondering why you wouldn't use one again.

[RB211]

Any reason you're not going with an acorn again? If it were me I'd try and keep all my machines running on the same hardware/software if I could, in case of breakdowns, or troubleshooting problems come up. I don't know anything about converted machines but would like to build a CNC wood router and separate plasma table in the near future. Not criticizing your choice just thinking that was the way I was planning on tackling the problem. I was also considering using an acorn, and was wondering why you wouldn't use one again.

Acorn is overkill for a small Taig but I was most certainly going to use another Acorn for the 12" lathe. I might just order the Acorn and use it now for this side project, move it over to the big lathe later.

[Sparky_NY]

Mesa 7i76 is pretty much overkill for the project you have in mind. Do you have a old computer around with a parallel port? If you do, one of the super cheap breakout boards will do the trick as long as it has a 0-10V feature for your vfd. I have used a hunyang vfd with linuxcnc using the modbus interface, works great and super cheap, only need a $5 usb to RS422 adapter, gets around the need for 0-10V AND even allows access to the VFD parameters etc.

My first adventure with linuxcnc was a 7x10 lathe that I cnc'd. I put linear rails on both axis. Just used a cheap CNC4PC breakout board and the parallel port on a $15 thrift store dual core SFF computer. Later, that machine was used in a actual shop for production of small motorcycle parts with great success.

Don't get me wrong, I absolutely love MESA hardware ! My present mill has the 7i77 / 5i25 combo as did a few others I have done. Its just overkill for a small Taig lathe. I didn't go to Mesa hardware until I went to servo retrofits.

[RB211]

Mesa 7i76 is pretty much overkill for the project you have in mind. Do you have a old computer around with a parallel port? If you do, one of the super cheap breakout boards will do the trick as long as it has a 0-10V feature for your vfd. I have used a hunyang vfd with linuxcnc using the modbus interface, works great and super cheap, only need a $5 usb to RS422 adapter, gets around the need for 0-10V AND even allows access to the VFD parameters etc.

My first adventure with linuxcnc was a 7x10 lathe that I cnc'd. I put linear rails on both axis. Just used a cheap CNC4PC breakout board and the parallel port on a $15 thrift store dual core SFF computer. Later, that machine was used in a actual shop for production of small motorcycle parts with great success.

Don't get me wrong, I absolutely love MESA hardware ! My present mill has the 7i77 / 5i25 combo as did a few others I have done. Its just overkill for a small Taig lathe. I didn't go to Mesa hardware until I went to servo retrofits.

Cool, my VFD has Modbus RS485 built in, so LinuxCNC knows how to work with that, pretty cool.

[Sparky_NY]

Cool, my VFD has Modbus RS485 built in, so LinuxCNC knows how to work with that, pretty cool.

Yea, the approach might be a bit different depending on the vfd. Different VFD's, different modbus addresses etc. There is a pre-configured one for the huanyang which I used. Only 2 wires to the VFD to control everything ! Its bi-directional too, I used the one of the outputs for a onscreen spindle load meter.

Linuxcnc can interface to just about any hardware you can dream up thanks to the power of HAL. I use a video editing device (Shuttle and ShuttleXpress) for a pendant, gives me variable rate jog and mpg click increments.

[RB211]

Yea, the approach might be a bit different depending on the vfd. Different VFD's, different modbus addresses etc. There is a pre-configured one for the huanyang which I used. Only 2 wires to the VFD to control everything ! Its bi-directional too, I used the one of the outputs for a onscreen spindle load meter.

Linuxcnc can interface to just about any hardware you can dream up thanks to the power of HAL. I use a video editing device (Shuttle and ShuttleXpress) for a pendant, gives me variable rate jog and mpg click increments.

I wonder if I can get LinuxCNC to run happily on a Raspberry Pi 4 with USB to parallel port adapter?

[macona]

Beaglebone supports linuxcnc. But either raspi or beaglebone, unless you have one already good luck.

USB to Parallel port adapters do not work with CNC, they cant handle the timing.

You could get a kflop and use the included kmotion cnc software that is included or use a plugin for Mach3. Thats what I use on my cnc mill (mach3)

There is also the ethernet smooth stepper which needs Mach3/4

For the rs485 you can get cheap usb-rs485 adapters on amazon. I picked one up to configure some big power supplies I have. Worked well.

[Sparky_NY]

I wonder if I can get LinuxCNC to run happily on a Raspberry Pi 4 with USB to parallel port adapter?

Many have ran Linuxcnc on the RasPi but I don't know about the parallel port adapter. I am guessing you found the Linuxcnc forum by now, that would the place to find that info or ask.

Edit: Searched around a bit. Apparently with the RasPi most use the GPIO pins rather than a parallel port. Actually pretty much the same thing. I found this one example that might be of interest. https://forum.linuxcnc.org/9-install...ns-only#203365 (note: the last post in that thread by PCW... PCW is Peter, the owner of Mesa, one extremely sharp guy !! )
Tech evolves so that example may not be the current trick setup, I only did a quick search.

Also, hope you already have your RasPi, they are near impossible to get these days, out of stock everywhere.

[danlb]

The RasPi should be more available soon. Adafruit noted that all of their production was being scarfed up by bots as quickly as it was made available. The buyers then turned around an sold at a 400% markup (or more). Adafruit has implemented a two factor authentication to slow down or stop the bulk buyers. We should see the results soon.

Dan

[RB211]

I have my rpi 4 already.

[Sparky_NY]

The RasPi should be more available soon. Adafruit noted that all of their production was being scarfed up by bots as quickly as it was made available. The buyers then turned around an sold at a 400% markup (or more). Adafruit has implemented a two factor authentication to slow down or stop the bulk buyers. We should see the results soon.

Dan

Its not all scalpers buying to resell. I have a friend that uses RasPi's in a commercial product he sells. He uses about 1000 a month and has been going crazy searching the world to buy them and keep production going. He is flexible too, can use nearly any version and still having lots of difficulty finding them.

[Sparky_NY]

I have my rpi 4 already.

Maybe I am missing something but I just don't see any benefit to using a RasPi for Linuxcnc other than its small size. For a CNC build the size shouldn't be all that important, a SFF PC is small enough compared to the machine size and footprint that it should be a non-issue. With a standard PC there is none of the problems with special versions / installs of Linux to support Linuxcnc, standard expansion slots, sometimes a printer port and serial port available etc. Many are now going to touchscreens for Linuxcnc and there are some really trick screensets to support that, does the RasPi have enough video power to support such a thing?

All the Linuxcnc builds I did used a SFF PC, a dual core which is plenty powerful enough for Linuxcnc. Some folks just use the motherboard which makes it even smaller to stuff into a electronics enclosure with the drives and other components.

It seems like using a RasPi (or a NUC for that matter) for Linuxcnc is a step backward and actually creates problems implementing it compared to a plain old PC. What am I missing?

[RB211]

Maybe I am missing something but I just don't see any benefit to using a RasPi for Linuxcnc other than its small size. For a CNC build the size shouldn't be all that important, a SFF PC is small enough compared to the machine size and footprint that it should be a non-issue. With a standard PC there is none of the problems with special versions / installs of Linux to support Linuxcnc, standard expansion slots, sometimes a printer port and serial port available etc. Many are now going to touchscreens for Linuxcnc and there are some really trick screensets to support that, does the RasPi have enough video power to support such a thing?

All the Linuxcnc builds I did used a SFF PC, a dual core which is plenty powerful enough for Linuxcnc. Some folks just use the motherboard which makes it even smaller to stuff into a electronics enclosure with the drives and other components.

It seems like using a RasPi (or a NUC for that matter) for Linuxcnc is a step backward and actually creates problems implementing it compared to a plain old PC. What am I missing?

My spare PC needs a video card, it's setup as a headless server at the moment. Although I do have plenty of 3000 series GPU's, they are all preoccupied... The rpi is free without a job, that's all.