Need 2nd opinion on Wiring diagram.. proximity - isolation - lpt.

[Doddy]

Some caution, and breadboarding required here. One problem is we're considering a theoretical model, not an electrical model of the EC300-ETH input circuitry. Once upon a time I sketched this out for this site but cannot find the post now.

It is something like (but not sure how precise, or even accurate this is, or the component values.... and I'm not about to dig out my UC300 to double-check)....



The problem is around the 3v3 operation of the internal logic on the EC300, which necessitates the use of the potential divider resistor network shown in the box on the right of the sketch.

This will allow high-intensity LEDs to illuminate even when the input is off (current path through R4/R1/R2).

OP: Just worth breadboarding one channel when you receive the isolator board. Consider your 300ETH-side LED indicators as sacrificial in the overall solution.