Upgrading a Chinese 3040t

[Richard Tymko]

I have a standard Chineses cnc 3040 from about 2017 and want to upgrade it to work with USB from a Raspberry Pi or a Beaglebone Blake. Any suggestions on what I would need or what you would recommend.

Thanks

Richard

 

[jcdammeyer]

I've run my mill with a Beaglebone Black and a cape that emulates a parallel port. There have been discussions on the LinuxCNC forum on using a Pi4. What specifically are you trying to accomplish and why one of those processors? What's wrong with the original controller?

 

[Richard Tymko]

So I want to upgrade because I do not have a pc with a parallel port and I lose some functionality using a usb to parallel adaptor. I can not get all the features I want with my current system. Also I would like to use something other than mach 3.

So you are going from your PC USB to your BBB parport then to the controller? Which cape are you using for your BBB. what controller board are you using?

 

[jcdammeyer]

http://xylotex.netfirms.com/OSCommerce/catalog/product_info.php?cPath=33&products_id=146

MachineKit is the LinuxCNC port used with this. The parallel port connection should plug into your existing Breakout Board (BoB)

If you don't have a BoB and just stepper drivers then you have all sorts of choices beyond a Beagle or Raspberry with LinuxCNC and something like the MESA 7i92H. LinuxCNC runs on lots of different surplus PCs. I bought two from BC Government Asset recovery. Dual boot with WIN-XP/MACH3 plus LinuxCNC. PMDX-126 BoB. But there are cheaper ways than a PMDX-126.

 

[Janger]

Another possibility... I bought the centroid acorn board mainly to get the software Cnc 12 that runs on the pc. It’s Ethernet based. When Linux gets complicated it’s complicated so I wanted to avoid that.

 

[Janger]

Pictures Richard of your machine?

 

[jcdammeyer]

Another possibility... I bought the centroid acorn board mainly to get the software Cnc 12 that runs on the pc. It’s Ethernet based. When Linux gets complicated it’s complicated so I wanted to avoid that.

I'll second that. LinxCNC, regardless of what anyone may say is complicated. Unless you buy all the hardware from one place and they provide the .ini and .hal files tailored to your hardware. And although there's lots of stuff out there on the web, some of it is old and some of it won't apply but you won't know that because you don't know what you don't know.

That's why I set up my mill as dual boot. But I must admit I'm leaning towards LinuxCNC. Once I can get the python apps for wizards and tool touch off installed and working. Haven't attempted that yet. And that's an example of why MACH3/4 is easier to use.

 

[Richard Tymko]

Well, I just decided to go the simplest route for me and that was to buy a PC with a parallel port. the PC can dual boot so I will just play with linux and mach3 to see what I can make work best for me.

Any comments on my thought process?

Thanks!

 

[Richard Tymko]

Pictures Richard of your machine?

This is my machines ...

 

[jcdammeyer]

Well, I just decided to go the simplest route for me and that was to buy a PC with a parallel port. the PC can dual boot so I will just play with linux and mach3 to see what I can make work best for me.

Any comments on my thought process?

Thanks!

Look inside the box and see if there's anything similar to a Breakout Board. (BoB). There are lots out there for not a lot of money. They allow you easily connect a parallel port to the stepper motors, relays and limit switches.

For my CNC Router I have a:
https://www.pmdx.com/PMDX-125
which has been replaced with the:
https://www.pmdx.com/PMDX-126
which I used for my Mill Conversion.

Although expensive the up side is the USB or Ethernet Smooth Stepper plugs into the top ribbon cable connectors or you can plug a parallel port cable from a PC directly. The photos show a smooth stepper and an expansion board.

It optically isolates the inputs but expects the outputs to be connected to stepper motor drivers that have their own isolation. It also has two relays, one that could be used for coolant (mist or floor) and one to run power to the spindle.
The second port only supports some of the I/O where the rest is dedicated to PMDX special I/O cards.

It also supports the Charge Pump feature which means if the PC crashes or during boot your spindle won't come on or stay on. Major safety issue feature and supported by LinuxCNC too.

In either case it's not really all that cheap. The PMDX-126 at $174 plus about $180 for a Smooth Stepper and $10 for cables almost makes
https://www.pmdx.com/PMDX-340
at $387 more attractive since it appears to include everything although I don't know if it works with LinuxCNC and it's out of stock at the moment anyway.

I'm running the MESA 7i92H
http://store.mesanet.com/index.php?route=product/product&product_id=303
into the PMDX-126 with LinuxCNC.

MESA has a few other Ethernet based BoB units with terminal strips etc. But they are all LinuxCNC only products.

Hence I went the simple way with the parallel port option.

 

[kevin.decelles]

Confused as to why a PMDX-#### is required at all for a smooth stepper? From the smoother stepper site, they show a direct ethernet/USB connection. I run the MESA 7i76e directly with linuxcnc. I'm missing something elementary here, someone point out the obvious for me? Thx!

 

[jcdammeyer]

The PMDX is my Break Out Board. The Smooth Stepper sits on standoffs above it as there are holes specifically for that. Ethernet into one side of the SS. Two 26 pin ribbon cables for the two parallel ports out another side running under the SS into the PMDX.

The elementary thing is that the SS only has ribbon cable connectors just like the MESA 7i92H. The down side of the PMDX is that it doesn't support the second port DB-25 pins 2..9 which are generally stepper outputs on the first parallel port. These pins are used for the custom I/O expansion. At the moment there is no custom MESA file to deal with the custom hardware.

If I knew for sure that I wanted to use LinuxCNC adn was starting from scratch then the MESA 7i76e is a much better deal since it includes the BoB. If you are running a PC with WIN-XP and MACH3 and you are happy with MACH3 and already have a BoB then the SS is a better choice.

And if you want to try LinuxCNC with your existing motor/limit switch/spindle power/ESTOP wiring then the MESA 7i92H is only $89US compared to $199US while the Ethernet SS is $180US.

Since Richard has an existing box that probably has a BoB that connects via parallel port cable to his PC it comes down to which OS he wants to use. I wanted to be able to swap back and forth.

But, if Linux is the destination with no looking back at MACH3/4 then the 7i76E is a better starting point since it includes not only the BoB but a 26 pin header that duplicates the pin out for a DB-25 pin parallel port to plug into an existing BoB.

One just has to know they want LinuxCNC.

 

[kevin.decelles]

Perfect , that explains it. My #1 criterion was no windows xp. I went limuxcnc which made the card selection easy.


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[jcdammeyer]

Maybe Richard could post some pictures of the inside of his control box? I'm curious what's inside that black box.

 

[Richard Tymko]

I will post pictures this week and look into those suggestions.
Thanks...

 

[Richard Tymko]

So finally had time to take some photos of my controller...

hope this helps with some suggestions.
I’m assuming that that is the BB (breakout board) that some of you have refunded?

do I need something better?

 

[jcdammeyer]

OK. Thanks for the pictures. The Break Out Board in yours also serves as the stepper motor driver board for all three axis. It's how they've kept the cost down. The power supply looks pretty straight forward with a toroid transformer and probably a bridge rectifier and capacitors for the stepper supply. Max 32VDC max maybe? A second winding on the transformer providing 8V to 12V for the 5V supply used for any logic signals that feed the ESTOP and limits back to the PC.

The building blocks are the same regardless of the packaging. PC parallel port to stepper driver and optically isolated switch inputs. Normally on the bigger systems the stepper drivers are separate modules. Depends on the needs of the motors.

Higher voltage to the motors usually means faster stepping with decent torque. Lower voltage just means slower max step rates.

So if you decide to upgrade I'd suggest you buy stepper motor drivers with high voltage ratings even if you start with your existing transformer/power supply. In the future you may upgrade the power supply.

 

[Richard Tymko]

OK. Thanks for the pictures. The Break Out Board in yours also serves as the stepper motor driver board for all three axis. It's how they've kept the cost down. The power supply looks pretty straight forward with a toroid transformer and probably a bridge rectifier and capacitors for the stepper supply. Max 32VDC max maybe? A second winding on the transformer providing 8V to 12V for the 5V supply used for any logic signals that feed the ESTOP and limits back to the PC.

The building blocks are the same regardless of the packaging. PC parallel port to stepper driver and optically isolated switch inputs. Normally on the bigger systems the stepper drivers are separate modules. Depends on the needs of the motors.

Higher voltage to the motors usually means faster stepping with decent torque. Lower voltage just means slower max step rates.

So if you decide to upgrade I'd suggest you buy stepper motor drivers with high voltage ratings even if you start with your existing transformer/power supply. In the future you may upgrade the power supply.

Thanks for that, My PC is all setup with Linuxcnc, now to get it configured to run my 3040. Fingers crossed.

 

[jcdammeyer]

Perhaps these will help?

I'm using a PMDX-126 BoB. It's set up so I can move between Parallel port WIN-XP MACH3 and Parallel port LinuxCNC.

John

 

[Richard Tymko]

Perhaps these will help?

I'm using a PMDX-126 BoB. It's set up so I can move between Parallel port WIN-XP MACH3 and Parallel port LinuxCNC.

John

Awesome, thanks. I will try them out.