Want to replace parallel port BOB with USB one.

Hello everyone,

I started building a DIY cnc many years ago and unfortunately life got in the way.

Control wise I got as far as assembling the stepper motor driver boards and the BOB and had the stepper motors wired up and working on the bench.

The drivers were from a kit by Lucas that I found on this forum.

(Old thread here https://www.cnczone.com/forums/open-...395-posts.html)

and these were the drivers I built THB6064 traditional description

I am in a position to restart the build but want to use a usb BOB instead of the parallel port one I have BOB4 description

I want to still use the driver boards I built.

Can anyone suggest a usb bob that might suit my needs? Or is there some sort of usb to parallel converter that works well?

Thanks for any advice.

What software will you be using?

Hi Gerry,

Thanks for replying.

I am open to suggestions.

When I had it 'working' before I was using Mach 3 and that seemed fine for what I wanted to achieve. Is that still an option? I mean I think I have the XP system with Mach 3 on it still in the workshop (garage) somewhere but I don't know if it still works. Also I wouldn't like to hang it on the web but maybe I shouldn't do that with the controlling pc anyway?

Mach 4 hobby doesn't seem too expensive.

Or maybe Linux CNC? I have some experiencing with Linux and once set up it is ok.

Could this be a solution? https://www.cnc4you.co.uk/UC100-USB-Motion-Controller

You might want to check out grblHAL. No SW license fees. It's a 32 bit version of GRBL and runs on quite a few different processors. https://github.com/terjeio/grblHAL I have a USB (and Ethernet if desired) breakout board for the Teensy 4.1 (600 MHZ ARM M7) that a number of people are using. I have a few BoBs with all the SMD components on it in my tindie store. https://github.com/phil-barrett/grbl...ster/README.md

Here's an earlier version of my system case. I'll be posting a full build description of this for my extruded AL router in the future.
Attachment 447592

Thanks. That is interesting. I am playing with grbl currently.

I have had a quick look at the drivers I made and it looks like they each want 5V on the ribbon connector. Could I break that out and power it directly from the grblHAL +5V output? Would it being enough amps (ma?) for my 4 boards.

https://www.cnczone.com/forums/attac...d=447594&stc=1

Here is my case.

https://www.cnczone.com/forums/attac...d=447600&stc=1

Yes, I think it would be fine. Maybe even powered by the USB +5V. Worst case, you would need to supply separate +5V (the BoB is set up to allow that). You should go through the exercise of adding up all the current draws for your drivers. If it adds up to more than 150 mA for your driver boards, then a separate +5V supply would be needed.

I do have one concern about your optoisolators, the data sheet seems to want fairly high current for the LEDs. While I think it would be ok, it is probably pushing the specs of the output drivers on the breakout board. The Avago data sheet doesn't seem to give the Vf value of the LED so I don't know what their forward current would be with 270 ohm resistors.

If you want to keep using Mach3, get a UC100 from CNC Drive. That's all you need.

I understand wanting to get away from the parallel port, but USB also has it's own issues. I would recommend going with Ethernet since you're upgrading and having to buy new components anyway.

or keep your BOB and go with Linuxcnc

Thanks for the responses everyone.

Hi Gerry,

I have a Mach3 controller. The old type which has DB25 parallel port and a USB to power the board. Can I use a DB25 to USB adapter/convertor and run it through USB of my laptop?

The other alternative is to buy Mach3 which is USB driven but its 4 times costly here.

Hi Tony,

Your controller sounds like mine. This is the easiest way of going from parallel to USB CNCdrive - motion controls

D

Quote:

---

Originally Posted by Tony_Stark

Hi Gerry,

I have a Mach3 controller. The old type which has DB25 parallel port and a USB to power the board. Can I use a DB25 to USB adapter/convertor and run it through USB of my laptop?

---

No, USB>>Parallel converters will not work with Mach3.
You can use either a UC100, or even better, a UC400ETH.

Thank you for reply.

It is not available in my country plus its costly . I shall buy the new mach3 usb 4 axis controller instead then.(chinese one) fits the bill and works.