EBAY USB Controllers

[ny_racer_xxx]

Isolation is overrated, until you need it.

Yah, ask me how I know!!!

[James Newton]

Isolation is overrated, until you need it.

And then it isn't enough. I would never hook my good machine up to something that could fry it. Always run from an older machine or a dedicated controller. And USB isn't isolated... nor is Ethernet really... although it's better. Just... use an old machine.

[dharmic]

Isolation and EMI tolerance are different things. Ethernet has far superior EMI tolerance to USB. Isolation is better too. Then there's the whole ground loop issue: Ethernet is a whole lot better at handling floating grounds than USB.

Switching from a YooCNC USB board to a UC400ETH was the best upgrade I've done on my machine. Still using Mach3, just popped the UC driver in and she goes like a charm. Interested in switching to the UCCNC software too at some point.

[ny_racer_xxx]

And then it isn't enough. I would never hook my good machine up to something that could fry it. Always run from an older machine or a dedicated controller. And USB isn't isolated... nor is Ethernet really... although it's better. Just... use an old machine.

Yes, I have my $30 ebay Optiplex 755 USFF that is only used for CNC.

The units on ebay say they are isolated, so I would assume its on the BOB side, no need to have on the pc interface side, as long as nothing passes the inputs/outputs on the bob.

I have nothing against a Warp 9 ESS, or the UC300ETH , just seems like a patchwork. To make it work right you need a BOB that has at least 2 parallel ports, and make safe, they need to be isolated. Gets expensive pretty quick...

Being that I run a plasma with this, from you guys are telling me, I'm better off with ESS rather than USB, that ebay unit for a 4 axis is $120... If it works..

CR

[OlfCNC]

And USB isn't isolated... nor is Ethernet really... although it's better. Just... use an old machine.

You are wrong on this one. Ethernet is isolated ... if we talking about isolated from the PC.

[dharmic]

Isolated BOBs are easy - $5 a pop on eBay, grab two if you actually need that many I/Os. They're dumb, all they do is isolate your controller and switch signal levels. And at that price, buy a couple spares in case something goes awry and you pop one.

Bang them into a UC-anything-ETH and you have a much smoother running machine than PC driven timing via LPT and you get nice connectivity to boot.

I have a great distrust for anything off eBay from China. The BOBs being so cheap are low risk, but something like that controller, well:
1. If anything pops despite the "isolation" they offer, chuck the whole thing instead of one cheap board.
2. Do you trust that they'll behave from a control point of view? That their timing spec is as advertised, that they can actually handle the voltages as advertised, that they will respond to the g-codes etc you want and do it properly, that there won't be any wonky edge cases eg with THC that they can't handle and that there's any support if things don't quite match up? I don't.

I think you're much better off running control software that's on a PC (ie easy to upgrade), that has a large user base (ie well tested) and that you can get some support for, ie Mach3 or something like UCCNC.

[ny_racer_xxx]

Isolated BOBs are easy - $5 a pop on eBay, grab two if you actually need that many I/Os. They're dumb, all they do is isolate your controller and switch signal levels. And at that price, buy a couple spares in case something goes awry and you pop one.

Bang them into a UC-anything-ETH and you have a much smoother running machine than PC driven timing via LPT and you get nice connectivity to boot.

I have a great distrust for anything off eBay from China. The BOBs being so cheap are low risk, but something like that controller, well:
1. If anything pops despite the "isolation" they offer, chuck the whole thing instead of one cheap board.
2. Do you trust that they'll behave from a control point of view? That their timing spec is as advertised, that they can actually handle the voltages as advertised, that they will respond to the g-codes etc you want and do it properly, that there won't be any wonky edge cases eg with THC that they can't handle and that there's any support if things don't quite match up? I don't.

I think you're much better off running control software that's on a PC (ie easy to upgrade), that has a large user base (ie well tested) and that you can get some support for, ie Mach3 or something like UCCNC.

I don't disagree with most of you points, but a few...

Find me $5 optically isolated bob, remember to get the most out of an ESS, you need at least two.

I paid top dollar for an "American" made Gecko G540, that was the biggest piece of crap I have ever owned, so just because it has a good following, doesn't make it a good product. Easy to setup yes, optically isolated yes, the friggin mosfets are grounded to the housing, so the housing has to be insulated and not star grounded, DUMB.

The system is only as good as the pieces you put into it, so if I buy a good ESS and a cheap BOB, if Chinese optically insulated BOB fries and sends it back through my ESS, then what did I save?

Pretty sure if I smoke something no matter where I bought it from, I'm buying a new one on my coin.

CR

[ger21]

Find me $5 optically isolated bob

5 Axis CNC Breakout Board Interface Adapter for Stepper Motor Driver pump | eBay

I have one sitting in front of me, that I'm using to test my $200 UC300.

If you want top of the line, buy a PMDX 126.

Right now, I'm leaning towards this board:
MB2 ESS ethernet smooth stepper BOB breakout out board [MB2]


This forum has been around for about 13 years. I'm not sure if I've ever read about anyone frying components from a faulty bob. This typically happens from faulty wiring, where even isolation won't usually save you.

I've been running a non isolated Xylotex board for about 7-8 years now, with no issues.

[ny_racer_xxx]

5 Axis CNC Breakout Board Interface Adapter for Stepper Motor Driver pump | eBay

I have one sitting in front of me, that I'm using to test my $200 UC300.

If you want top of the line, buy a PMDX 126.

Right now, I'm leaning towards this board:
MB2 ESS ethernet smooth stepper BOB breakout out board [MB2]


This forum has been around for about 13 years. I'm not sure if I've ever read about anyone frying components from a faulty bob. This typically happens from faulty wiring, where even isolation won't usually save you.

I've been running a non isolated Xylotex board for about 7-8 years now, with no issues.

I ordered one after I wrote this!!!

I fried output 1 on my PC from a non isolated BOB. There's no faulty wiring, just a flyback from the plasma. I imagine it would have fried the ESS if that's what was connected..

I looked at the UC300, you need a mother board also to breakout the LPT ports, the UC400 looks like a better setup. They are like a $160 here in the states..

[ger21]

With the motherboard, the UC300ETH is about $30 more than the UC400ETH, and gives you 5 ports instead of 2, and is capable of higher pulse rates. If you need more than 2 ports, the UC300ETH is a much better deal. Especially when it came with a free license for UCCNC when it was first released.

Plasma makes a big difference, when you're talking about isolation.

[ger21]

I ordered one after I wrote this!!!

Just a head up on these $5 breakout boards.
I wired up some switches, and plugged it into my UC300. The relay and outputs worked, but not the inputs.
After a little googling, it appears that the inputs do not work unless you also connect a 12V-24V power supply, in addition to the 5V. I have a 24V supply, but I'll need to go grab a cord in the morning.

[dharmic]

I have the same BOB, Gerry - or at least a BOB that looks identical to the one in the photo, and it cost me about $5 delivered.

Everything on mine works. I'm using inputs, outputs, 0-10V for spindle and PWM (on the same channel via a small FET inverter) to drive my laser. I have a 12V supply for the laser which is plugged in anyway, which is probably why I never hit your issue.

But yep: that BOB is fully opto isolated, dirt cheap, available from multiple vendors yada yada yada and mine's been running faithfully for a while now. One of those times where an ebay cheapo bargain seems to actually have been a bargain.

ny_racer_xxx... I agree on the gecko. Nifty little unit but looking at a client's I was glad I didn't succumb to the raging boner CNCZone seems to have for them - I much prefer separate drivers for each axis which have better grounding, a little more oomph and much better serviceability if anything goes runny.

The BOB we're talking about uses the same opto isolator chips that much, much more expensive BOBs use. These things tend to fail by frying the diode, so any craziness on the driver side usually blows the opto and that's it. Kinda the point of using them, if it gets exciting they protect the expensive fruit further back along the chain. I'm very, very comfortable treating these $5 BOBs as fuses for my UC400.

[ny_racer_xxx]

With the motherboard, the UC300ETH is about $30 more than the UC400ETH, and gives you 5 ports instead of 2, and is capable of higher pulse rates. If you need more than 2 ports, the UC300ETH is a much better deal. Especially when it came with a free license for UCCNC when it was first released.

Plasma makes a big difference, when you're talking about isolation.

Yup, Plasma is a whole other deal as I'm learning... The G540 was fine when I was just running the router, crapped out all the time with the plasma... The C10 has been great till I got a misfire on the Plasma and it popped the output 1 on the PCB parallel port...

I agree 110%, use the isolated $5 BOB as a fuse.

Thanks for the heads up on the powering the BOB... I have prox's for my homing switches, I believe that board will accept the voltage on the inputs.

Can you power those BOBs with a 5V PS or do you have to use the USB? Can you power the whole with 12V or do you need 5V and 12V?

That all in one on feebay is looking a lot more simpler......

CR

[dharmic]

I leave the USB disconnected. There's a couple 5V terminals down the bottom somewhere, presumably for wetting outputs or something, but they're connected straight to the USB 5V input so it'll take it from either side.

Can't remember now whether I'm running the whole shebang off 12 and there's a regulator on board, or I have a 5V supply somewhere else in my controller box (possibly even off the UC400ETH) that's doing the job. Not much use to you, I know, sorry.

[ny_racer_xxx]

Thanks for the info, I'll have to mess with it....

This is the Kelling board, looks exactly the same...

CR

[dharmic]

Yep that looks pretty much identical. No doubt these $5 cheapies are a ripoff of something that someone's made to sell for $100 a pop.

[ny_racer_xxx]

Yep that looks pretty much identical. No doubt these $5 cheapies are a ripoff of something that someone's made to sell for $100 a pop.

I have not seen these anywhere but ebay and Kelling, I think it's the opposite, I think Kelling is selling a $5 board for $30!!!! From what I'm getting from you guys is that they are kinda quirky, so maybe somebody gave up on the design and somebody else picked up the pcb design, or bought a huge lot of them.

CR

[dharmic]

Quirky? Nah - I've not had problems with mine at all. 5V for logic power from the UC400ETH, 12V for wetting input contacts enough to fire up the opto diodes (5V won't do it), plug it in and off it went.

The resellingkelling concept makes sense. Even on eBay you can pay much, much more for one of these boards - I figure some sellers are aiming for people who think "Oh, costs more, must be better".

[asuratman]

Hi ny_racer_xxx,
What motor and driver you will use with this cheap BOB? I saw a lot of cnc kit packages sold with this cheap BOB for free, such as wantai motor or long motor...

[ny_racer_xxx]

Hi ny_racer_xxx,
What motor and driver you will use with this cheap BOB? I saw a lot of cnc kit packages sold with this cheap BOB for free, such as wantai motor or long motor...

I just meant quirky on the setup, two different voltages, kinda weird, what not one voltage, dc=dc convertor???

I'm a Keling boy, they have been pretty good to me, I have KL5056 I believe they are...

CR