And for a non galvanic isolation RS485 still all the
0v commons of the circuit should be tied together . And to the DIRT at one end only the MASTER END is it true for this aswell .

this???, what this

///// If you check datasheet LTC they connect floating circuit common to shield ? and then some filter and then to Dirt but only after isolating it from the circuit common (processor side) .If I do not use galvanic isolation I have a single common for every circuit ,I ask according to it . please check LTC datasheet 1535fs.pdf \\\\\\\


Any Leftover twisted pair in the cable what to do with em ,I hope they will resonate to some frequency ,and if grounded at one end would still resonate ,what to do .
resonate ???

/////// I mean any leftover wire inside a cable bunch ,what to do with em if left alone the unused wires will self-reso-nate and couple noise into the datawires. If the unused cables are left
open, they will resonate at all sortsof strange frequencies. If they are grounded at one end, they will
resonate at L/2. If they are grounded at both ends, they resonate at L/4 .\\\\\\\

Kindly/