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View Full Version : Do I need a BoB when replacing a parallel port connection with a UC300 or UC400?



ian823478
11-03-2021, 09:13 PM
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

Doddy
12-03-2021, 08:20 AM
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.

A_Camera
12-03-2021, 09:49 AM
You need the BOB also for optical isolation from the drivers.

Doddy
12-03-2021, 10:09 AM
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 :-)

ian823478
12-03-2021, 12:11 PM
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)
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

Doddy
12-03-2021, 01:19 PM
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.

ian823478
12-03-2021, 01:40 PM
Hi Doddy
My fault for not giving much detail, heres a couple of pics from the manual
297092971029711

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

Ian

Clive S
12-03-2021, 01:51 PM
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)
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

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

Doddy
12-03-2021, 02:05 PM
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?

ian823478
12-03-2021, 02:28 PM
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!

Doddy
12-03-2021, 02:31 PM
Nah, you'll need a common ground in any case between the UCx00 and the interface so that's largely by-the-by. I'm surprised you had that problem - but electromagnetic is all black magic to me.

A_Camera
12-03-2021, 02:48 PM
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?

Well, that's not entirely true... The UC300 and 400 needs some sort of a BoB, because you need to split the contacts. Doing that without any BoB is possible, and as you said, most drivers have optical isolators anyway, for for that, you don't need a BoB but you definitely need some way of splitting the signals and lead them to the right contact on each driver. So "easy" is a very wide word. With a BoB it is easy, but without it is not so easy.

A_Camera
12-03-2021, 02:53 PM
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)


Be aware that many drivers also implement optical isolation the wrong way, so in reality, even if there are opto couplers on the driver PCB and they claim optical isolation, it does not mean that it provides protection when needed. I tried to google documentation about the driver the Op mentioned but I failed, so I have no idea how it is actually built.

Doddy
12-03-2021, 02:54 PM
That control box (System 4C - I've found the PDF for it) - implements the functions of the BoB across 2-3 boards. It's fine. Just don't try to power the UCx00 5V supply from it (100mA max).

Doddy
12-03-2021, 02:59 PM
Well, that's not entirely true... The UC300 and 400 needs some sort of a BoB, because you need to split the contacts.

Ah, I think I see where our thoughts are not quite joined up - I'm talking (and I'm interpreting Ian's intent here) - of connecting the UCx00 to the 25 pin D-Sub connector on the control box, using the internal System 4C components that implement the BoB and the Driver electronics. NOT, taking the UCx00 device to connect direct to the drivers.

ian823478
12-03-2021, 06:49 PM
Ah, I think I see where our thoughts are not quite joined up - I'm talking (and I'm interpreting Ian's intent here) - of connecting the UCx00 to the 25 pin D-Sub connector on the control box, using the internal System 4C components that implement the BoB and the Driver electronics. NOT, taking the UCx00 device to connect direct to the drivers.

Doddy, you have interpreted my intent correctly :friendly_wink:
So connection wise I think I'd only need a D-sub 25 pin connector to solder on to one end of my lpt cable.

I'm hoping you were meaning the main board 12V (12-24) supply for the UCx00 when you mentioned 5V.:friendly_wink:
I had realised the 12V board supply isn't rated highly enough for the UCx00, which is a pity.

Back in 2012 I did post on here a few times while I was trying to sort out the earthing faults, but it looks like that is a time that has been lost to internet history!

A_camera, sorry I didn't explain things more clearly :dispirited:. If I can manage it, I'll post the manual and assembly pdfs....
Here we go, at least they are on the site if anyone needs them..
2971329714

Ian

A_Camera
12-03-2021, 08:46 PM
I see. Thanks for clearing the confusion. Yes, that's easy to do. You just plug in the UC400 to the DB25 on the box. No need of soldering because there is a ready made ribbon cable which is delivered with the UC400, which is the obvious choice for you. Just connect that to a small psu and to the LAN and off you go. It should work immediately once you have configured it. Will you be using UCCNC as well? I think it would be the best and maybe CNCDrive has some special deal when you buy both. I got my license almost for free when I bought my UC300ETH some years ago.

ian823478
13-03-2021, 01:37 PM
Well I've spent some money...
Dean only stocks the UC300ETH and AXBB so I've ordered a UC400ETH direct from CNCDrive.
We'll see how buying from Europe works these days...
I'm expecting to have to pay the VAT when it gets over here. I think I should save about 25 compared to buying from CNC4YOU.
I didn't order the UCCNC software cos I was chugging along OK with Mach 3.
I'll let you know how it goes.....

ian823478
27-03-2021, 09:28 PM
Hi folks
I said I'd let you know how buying direct from CNC Drive went:
I placed an order for a UC400ETH
I quickly received a paypal invoice for 128 euros confirming they were in stock.
I heard nothing for a week so sent an email, it turned out they were out of stock and would be for another week.
After the week I received a DHL email with no useful on it.
I emailed Balazs and he immediately provided a tracking number which showed it was about to be picked up from CNC Drive.
- it arrived the next day! The tracking showed it was flown over.
So if in stock, delivery is super fast. I'd just email them first to confirm an item is in stock.

I've got the UC400 talking to the computer, will connect it to the mill when I've got it safely in a box.

Ian

Clive S
27-03-2021, 10:06 PM
I would be interested if you had any import or other taxes added. Thanks

ian823478
28-03-2021, 07:44 PM
Good news and Bad news............
Good, I have the mill under control from mach3 via the UC400ETH :smug:
I had to fiddle around a bit, the CNCDrive manual didn't work perfectly for me.
Bad, I've discovered I hadn't kept a backup of my mach3 machine profile somewhere other than on the computer that I used to control it (and which died a sudden death) :thumbdown:
So I am plodding through ALL the settings, including faffing with the acceleration etc.
I'm sure everyone else is much more organised than me, but if you haven't got your profile saved somewhere else, I really recommend you do it asap!

dazp1976
25-04-2021, 04:30 PM
Good news and Bad news............
Good, I have the mill under control from mach3 via the UC400ETH :smug:
I had to fiddle around a bit, the CNCDrive manual didn't work perfectly for me.
Bad, I've discovered I hadn't kept a backup of my mach3 machine profile somewhere other than on the computer that I used to control it (and which died a sudden death) :thumbdown:
So I am plodding through ALL the settings, including faffing with the acceleration etc.
I'm sure everyone else is much more organised than me, but if you haven't got your profile saved somewhere else, I really recommend you do it asap!

Good tip.

Did you have any import charges to pay when you got the goods from CNCDrive?.
I've just got my quote back for a 'couple' of bits.