Hybrid View
-
02-11-2018 #1
-
02-11-2018 #2
It's worth highlighting the main reason opto-isolators are added to BOBs is for protection.
Using a parallel port, get something wired wrong, or have something short and connect power to pins they can't withstand, then more than likely your PCs parallel port (and likely entire motherboard) will be dead.
With newer motion controllers, the path of destruction from a wiring problem isn't likely to be as long, but it's still potentially a couple hundred pound controller that could be releasing it's magic smoke.
It's a calculated risk not using them, but at slow speeds, they shouldn't cause any problems. I certainly wouldn't be searching out a BOB without them, unless I was really going to be pushing pulse rates.
Regarding suitable motors.
A good starting point would be to try and find out the torque for the existing motors, or even a datasheet with torque curve (it's surprising what a google for the model number turns up).
You can then run a few figures and see how the various options compare. You'll likely find some suitably geared NEMA23/4s provide better performance than NEMA34s directly coupled, especially when running from lower voltage.Avoiding the rubbish customer service from AluminiumWarehouse since July '13.
-
03-11-2018 #3
-
04-11-2018 #4
adding more detail to post 7 for any one wanting to use a BOB with opto-isolated outputs and stepper drivers with opto-isolated inputs
the problem with the BOB supplied as part of the kit is ue use of the slow PC817 opto-isolators used for the outputs
I would expect the DM860A stepper drivers would have a PC817 on the enable input and a high speed isolator like a HCPL2531 for the step and direction inputs
as used on this Tormach driver input
the diagram is from
https://www.cnczone.com/forums/torma...ml#post2107952
if I used a breakout with opto-isolated outputs then I would look for a BOB like this -
https://cnc4you.co.uk/resources/Brea...ard%20HG08.pdf
or this
http://www.electronics-lab.com/proje...r-cnc-routers/
they are just two of example found
JohnLast edited by john swift; 04-11-2018 at 12:23 PM.
Thread Information
Users Browsing this Thread
There are currently 2 users browsing this thread. (0 members and 2 guests)
Similar Threads
-
Sieg X3 size conversion kits - what is available?
By men8ifr in forum Milling Machines, Builds & ConversionsReplies: 0Last Post: 13-10-2018, 05:06 PM -
eBay: Bridgeport J Series Turret Mill
By steve400 in forum Items On eBay UKReplies: 0Last Post: 24-04-2017, 04:11 PM -
Bridgeport series 1 MDI / CNC tooling
By drumsticksplinter in forum Milling Machines, Builds & ConversionsReplies: 7Last Post: 08-03-2013, 04:47 PM -
Complete conversion kits?
By leitzscope in forum General DiscussionReplies: 3Last Post: 01-05-2010, 07:57 PM
Bookmarks