Do I need a BoB when replacing a parallel port connection with a UC300 or UC400?

Hi Guys
I have a basic system consisting of a XP PC with parallel port connection to a DIYCNC system 4 package that controls 3 steppers on a SX2 type mill. I use mach 3 and CAMBAM.
The XP PC has packed in and I thought it would be a reasonable change to use a spare laptop which wouldn't have to live in the garage. I've been trying to learn a bit over the last few days, and get the impression ethernet might be less prone to problems than USB.
I had assumed I needed the UC300ETH, a power supply for it and the parallel cable would go straight from the UC300 into the original parallel connection on the controller. Now I've cottoned on to the UCSB BoB.
Is a BoB essential, or just a tidy way to do things?
Also, the UC needs a 12-24V PSU, is there any reason an old laptop charger rated at 19.5 V 4A couldn't be used?

Thanks
Ian

The UC300ETH could interface directly with your existing parallel BoB, provided you have a 26-way IDC to 25W-DSub ribbon cable (I think one comes with the UC300ETH - you to check). Obviously it means sorting out the physical layout to support this - you to check.

The UCSB BoB is a high quality, robust BoB, nice design but at a price. If your existing BoB works robustly with you machine then I wouldn't rush to replace. If you was in this game (of replacing) then I've suggest looking at the AXBB instead of the UC300ETH/UCSB combo to see if that would match your needs.

A laptop charge would work for the 12-24V supply.

You need the BOB also for optical isolation from the drivers.

For clarity, OP mentions a controller, previously connected to desktop. To OP, that “controller” IS a BoB. My earlier suggestion is to retain that as your Bob rather than replace. A-Camera is correct, you need a form of Bob, whether that legacy equipment or as a functional block on an integrated system? Such as the AXBB)

Just to contradict the last post. The (stepper) driver normally provides the optical isolation, rather than the BOB but the BOB typically provides the optical isolation for the sensor inputs. All good stuff.

Some BOBs do provide optically isolated outputs to the (stepper) drivers, absolutely. But I’d suggest 95% (random number, guess) of the enthusiast grade machines will have optical isolation within the driver, and adding it also to the BOB is not required (and can be detrimental)

Best thing is, get a photo of your control box and will give you a list of conflicting advice and options to play with :-)

A_camera, Doddy, thanks for replies.
I think the existing system will have the opto isolation built in,I'll try to attach Ist page of manual. (I got it in 2012 and the guys website doesn't seem to exist any more)
Attachment 29708

If I don't need a new BoB I guess the AXBB if probably overkill for my setup and I'd look at the UC400. In the UK I can only see them for sale at CNC4YOU and Stoneycnc in Ireland. Are there any other outlets you guys are aware of?

Cheers
Ian

Ian, I apologize - I had made an (I think) invalid assumption - sounds like your setup has the BoB and Drivers installled onto the single board (again, an image would help but it certainly sounds that way - and I am familiar in passing with that sort of board). But, yeah, you should be able to plug a UC300/UC400 into that without any real surprises. Again, you'd need the ribbon cable, but that's all doable.

I bought my UC300eth from CNCDrive directly with no problems (pre brexit/corvid), and an AXBB from another member of this forum, but that's for themselves to offer if the opportunity remains.

Unspoken, but going for those controllers opens up the option of replacing Mach3 with UCCNC - most people that have tried this seem to prefer it to Mach3 - I certainly do. You can download a copy of their software - without license file it only operates in a demo mode, but enough to get a feel for it.

Hi Doddy
My fault for not giving much detail, heres a couple of pics from the manual
Attachment 29709Attachment 29710Attachment 29711

I don't have motor control, just the 3 steppers.

Ian

Quote:

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Originally Posted by ian823478

A_camera, Doddy, thanks for replies.
I think the existing system will have the opto isolation built in,I'll try to attach Ist page of manual. (I got it in 2012 and the guys website doesn't seem to exist any more)
Attachment 29708

If I don't need a new BoB I guess the AXBB if probably overkill for my setup and I'd look at the UC400. In the UK I can only see them for sale at CNC4YOU and Stoneycnc in Ireland. Are there any other outlets you guys are aware of?

Cheers
Ian

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Not sure but I think Dean Jazzcnc might stock the eth version

Okay, I take it back. That's a new configuration for me. But the advice still stands - you can connect the UCx00 easily enough (though options to incorporate into the physical enclosure are a bit more limited). If that big PSU is a 24V DC powersupply for the board then why not slave the power from that?

Doddy, good idea re the power supply. Doing that wouldn't create any risks of earthing loops would it? I only ask cos I had a nightmare when I first built this kit with steppers twiddling randomly while I watched. Turned out to be entirely due to my ignorance in that I thought I was doing a better job by earthing both ends of the shielding on the stepper cables :dejection:
Edit: bugger. Power supply is 27V, just enough to exceed 24V max for UC400!