Quote Originally Posted by Robin Hewitt View Post
If you want to reduce electrical interference put in a fast diode to VCC to dump any big spikes and look for current rather than voltage. (To look for current stick in an opto isolator)

OK. But i will need separate power supply for that optocouplers, yes? Now what comes to my mind is that my Galil DMC-2183 & 2 ICM-20105 Opto I/Oboard maybe has that already . later will read again the 300 pages manual