Quote Originally Posted by Hatchett Job View Post
You guys have started to lose me with the Opto isolators chat, can you put it in layman's terms?
Also the relevance of the frequency?
I'm good at making stuff but electrical engineering and computers are not my strong point.
The 2 big black spider looking things are buffers.
The 5 little black things on the left with 4 legs are optocouplers.

The buffers are to smooth things out.
The optos can sometimes be slow and cause pulse problems. However, These boards don't use opto on the outputs so this is not your problem.

In a nutshell.
Optos allow 2 voltages to work together, it acts as a switch via a light diode.
So you can use say 24v limit switches into the opto and then that can signal out to your 5v parallel port without it blowing up.

Using the higher 24v on switches and the like helps to reduce false triggers as it is less susceptible to electronic interference from vfd's etc than a fully 5v system.