View Full Version : Breakout Board Comparison

25-03-2012, 11:26 PM
Dear all,

Does anyone have any experience of the OPPB and UNIPORT breakout boards available from diycnc.co.uk? I'm a noob and just starting out looking at what equipment I need. The two boards on this site look good but I'm not really sure what you get for the extra money when you buy the OPPB board.



26-03-2012, 06:34 PM
I have a UNIPORT, just like the one in the picture. I couldn't get the charge pump (PC present signal) to work with LinuxCNC, I think I had the same trouble with Mach 3 too. Apart from that there is not much more I can say, totally faultless, transparent in operation, in fact I just had to check to make sure it was still there :wink:

The UNIPORT is powered from the PC by a USB cable, or some other 5v supply.

It looks like the OPPB requires a 15v or above power source - you can see the big heatsink which probably cools the onboard 12v regulator. It has outputs providing 12v and 5v if you need them.

The UNIPORT has five optical isolated inputs, you can see the row of little 6 pin chips. Optical isolation helps protect the board and you PC from any nasty external voltages.

It looks like the OPPB has optical isolation on all connections back to the PC (?) and not just the five external inputs, a full 17 little 4 pin chips in fact!

So, OPPB has more flexibility with respect to power supply and provides the attached PC more protection. I think.

John S
26-03-2012, 08:53 PM
We had exactly the same problem with the Uniport.
Had to go down to Droitwich and take the board out and send it back with a Dell computer that it wouldn't run with.
Roy had to modify the board and rob one of the inputs to amplify the signal.

Then had the same problem on the System 1 board and 3 or 4 had to go back and have the same thing done.
Managed to get Roy down and sort this at our place so that saved a trip.

Then had a problem with the spindle speed board not putting out 10 volts when the cable was about 6 feet long. This time Roy wouldn't come down even though the machine was due to go right up north.
had an electronics guy look at it and the 12v to 12v DC convertor was the smallest available. Changed this to a larger unit [ cheaper as well !! ] and that cured the fault.

So my experiances haven't been that good. I now have my boards made for me, not cheap but 110% reliable.

26-03-2012, 09:45 PM
Hmm, this all sounds a bit iffy to me. Can anyone recommend a good breakout board that will get me going and that I can get in the UK? I'm probably looking in the 50 to 60 price range. Is the UIM2901-5A MACH3 breakout board available from Zapp any good?

John S
27-03-2012, 12:28 AM
Looks a decent board from the spec, nearly bought a couple the other week then found a stack of C11G boards in a drawer so decided to get rid of these first.
I'm waiting for Gary to have another 20% off weekend, last one was end of February so next one will probably be end of May when his VAT's due again. :whistling: