(optical isolation)

a Tutorial

Unexplained System Damage? Strange Outages? Data Errors? Ground Loops?
Stop Ground Loops from Wreaking Havoc with a Opto Isolator - (Optical Isolation).

Opto-Isolator (optical isolation)

A ground loop is a current across the cable, created by a difference in potential between two grounded points, as in two buildings connected by a long run of RS-232, RS422, RS485, RS530 or other data lines cables. When two devices are connected and their ground potentials are different, voltage flows from high to low by traveling through the data cable even the ground wire. If the voltage potential is large enough, your equipment will not be able to handle the excess voltage, and one of your ports will be damaged. Even small ground loop voltages cause transmission errors with data signals riding on top of the ground loop current.

At worst ground loops are a long-term condition that can slowly heat, and even cook your circuits. The chips have a higherthan normal failure rate. With the test equipment and tools available in the ordinarily data communications shop this phenomenon is hard to pin down and prevention is some times the easiest solution - if you are getting read errors or early life component failures. Use optical isolation or fiber optic cable on all your long data lines. In fact Opto-Isolators make great surge protectors up to the arc-over point of the chip,  but

When you link two devices powered by separate AC sources you create the potential for a ground loop surge a damaging electrical condition that can destroy your computer and wipe out data. Opto-lsolators interrupt that lethal pathway by completing the connection between the two devices using an internal fiber optic link.

Data signals, converted to light pulses inside the Isolator, continue along on the circuit. But the fiber optic air gap stops ground loops from wreaking havoc with your hardware.

With Opto-lsolators, your equipment is effectively isolated from ground-loop potentials.

Telebyte Technolgy
RS232, RS422, RS485, V.35 Opto-Isolator

Patton Electronics
RS232 Opto-Isolator

Black Box
RS232, RS422, RS485, TTL, Data Isolator

ARC Electronics
301-924-7400 EXT 25

E-Mail us at - arc@arcelect.com... 

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