| Electronics > Beginners |
| RS485 Ground isolation |
| << < (3/3) |
| T3sl4co1l:
Even Ethernet is not perfectly free, as it has a 1.5kV limit and the isolation is galvanic, not RF (there's a 1nF to ground to knock down peak ESD voltage). Obviously, a far sight better than RS-485, still. :) The most truly differential is propagating EM waves, I suppose (confined to a fiber or waveguide, or otherwise)? Yeah, RF bypass caps can help. :-+ Tim |
| Brutte:
The RS-485 signal is differential but only within common mode range. Typically +12V down to -7V with respect to GND pin of transceiver. If you exceed this range then it stops being differential. Just keep A and B within these limits. Of course the idea with third wire is ok. What about a latched comparator that senses for +12V and -7V violations? That could be helpful in your development. |
| mikeselectricstuff:
For one-way comms, you can use passive-input isolators like IL610, which are truly differential and don't care about the common-mode voltage. Loading is quite high so only viable for niche applications, but can be very useful. |
| Navigation |
| Message Index |
| Previous page |