Page 1 of 1

Acorn Ribbon Cable Output Connection

Posted: Wed Mar 03, 2021 6:14 pm
by Threedj16
For space reasons, I cannot use the current rev Acorn's relay output board and instead have slim DIN relays (24v coil, 7ma). They were already incorporated into my setup when I changed directions and swapped to Acorn. So I've searched the forum and found a few references in the Acorn spec manual, but wanted to check, as it appears left over from the previous board. The image references below show screw terminal output, which looks like it's from the previous board, before external relay board. The spec chart also shows 24v, but that appears to also be from the previous board. From looking at the relay board itself, it appears 5v is currently used for the relay board.

So my question is can I connect to the ribbon cable header and run it to my 24v supplied slim interface relays? The concern is will the Acorn board still handle sinking 24v like the previous board? Can't find any schematic of the new rev Acorn board anywhere to verify if this is possible.

The old board would be no issue. I have an old board, just it's licensed for lathe and the new board is for my mill. So guess the option if the above isn't possible, just swap beaglebones on boards so the license types/serials match the rev board I need. The lathe can handle the space for the new relay board, though I would prefer to swap to slim DIN relays on the lathe too.

Oh yeah, the other obvious solution (not really) of using 5v slim interface relays is I cannot find any that exist. 12v seems to be the lowest coil voltage for this particular style. Not to mention at 16-22 bucks a pop x8, really can't see replacing them. So hoping the new board can still sink 24v.

Anyway, here are the only references I can find:

Link:
https://www.centroidcnc.com/centroid_di ... manual.pdf
Capture.acorn2.JPG
Capture.acorn.JPG

Re: Acorn Ribbon Cable Output Connection

Posted: Wed Mar 03, 2021 9:57 pm
by Gary Campbell
Yes you can, I do it on most every build. Split the ribbon and connect pin 1 to 24v com. Connect 2 thru 9 to the negative coil, usually A2. All positive coil connections to 24+

Re: Acorn Ribbon Cable Output Connection

Posted: Wed Mar 03, 2021 10:45 pm
by Threedj16
Excellent, much appreciated. That makes things so much easier. I'd already bought a connector and pins before realizing the new relay board operated at 5v.

Thanks

Re: Acorn Ribbon Cable Output Connection

Posted: Fri Mar 05, 2021 2:00 pm
by martyscncgarage
CNC4PC now has a terminal block that can be used to extend the distance between Acorn and the relay board or connect opto coupler relays, solid state relays etc. DO NOT CONNECT relays with coils or directly connect VFD's to the outputs. You *MAY* damage the outputs on Acorn.
https://www.cnc4pc.com/c95-breakout-board.html

Sample 5V NPN relay board:
http://www.mdfly.com/products/8-channel ... g-npn.html

Acorn specifications:
https://www.centroidcnc.com/centroid_di ... manual.pdf

Don't do it unless you know what you are doing! ;)

Re: Acorn Ribbon Cable Output Connection

Posted: Fri Mar 05, 2021 2:12 pm
by Threedj16
That terminal connector would be nice, but I've already bought pins and connectors to just make up my own cable. That spec manual is the same as I linked to in my first post. They really should update the parts I highlighted if it's indeed no longer correct.

Re: Acorn Ribbon Cable Output Connection

Posted: Fri Mar 05, 2021 2:16 pm
by martyscncgarage
Threedj16 wrote: Fri Mar 05, 2021 2:12 pm That terminal connector would be nice, but I've already bought pins and connectors to just make up my own cable. That spec manual is the same as I linked to in my first post. They really should update the parts I highlighted if it's indeed no longer correct.
Spec is correct....