Re: Input Isolation / Optocouplers

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "peter_cassar"
<pjcassar@h...> wrote:

> Hi Folks,
>
> Have you any suggestions for input isolation. I'm wondering what

you

> guys are using between the PC Parallel Port and your stepper driver
> boards. Curcuit and design ideas are welcome. I plan to use some
> 4N25 optocouplers to do the job. I need to figure out how to

connect

> them up. My Driver board inputs are pulled high so it might be

tricky.

>
> Regards,
> Peter.

You could use 6n137 it's a high speed and have a high CTR , you can
have it complete isolated from the conputer including ground.
It will work with 1.6 miliamp from the paralel port.
You'll need a buffer to drive the 4n25. 6n137 no need for it.
We use 6n137 on our board to have a complete isolation from the input
including ground. http://www.maquitronic.com.br/smc1600%20english.htm