Optical isolate Xylotex issure

[monte55]

I plan on using the Xylotex 4 axis driver for my project. I have read where people connect them directly to the computer with no problems. But if you do
have a problem then we have no protection. Correct? I also have read where
it was suggested to optically isolate the driver from the computer. It makes since to me. But by doing so does this complicate the wiring much? Has anyone done this? What are your thoughts? I believe I'll also have homing and limit switches if I can figure it out. Also what isolator board would
work well with this driver. Thanks ...........Nick

[Torchhead]

Optical isolation has two functions: first to keep voltage coming back from the drives from causing problems with the PC parallel port. Highly unlikely unless there is a major failure of the on-board logic on the Xylotex. There have been very few reports of Xylotex step and dir connections causing any problem with the parallel port on a PC.

Second function is to isolate the grounds to eliminate possible conducted noise across a common connection. That requires that both sides be running on separate power supplies and that the xylotex supply is not referenced to the PC ground side.

Isolation for logic inputs to the parallel ports (e.g. home and limit switches, etc) is more important from a noise and voltage perspective.

An equal amout of protection for the Step and Dir inputs from the parallel port can be had by putting in a stage of "buffereing" between the PP and the Xylotex inputs. The buffers in the breakout will take the punishment rather than the port.


The Mini-io we sell has a direct ribbon cable connector to the Xylotex Driver cards and has the buffered Step & Dir, drivers for relays and 5 opto isolated inputs for homes and limits. On board split supply with separate grounds for the isolators.

Tom Caudle
www.CandCNC.com