How do you design remote I/O networks for distributed automation?

Remote I/O design considerations: network topology (star, ring, daisy-chain) based on redundancy needs, distance limitations (Ethernet up to 100m per segment, fiber for longer), I/O point density and distribution, scan time requirements, and environmental conditions. Implementation: select remote I/O nodes appropriate for location (hazardous area ratings, temperature range), design network infrastructure (cables, switches, junction boxes), configure communication parameters and addressing. Test network under load conditions. Consider diagnostic capabilities, spare capacity for expansion, and maintenance access. Common protocols: EtherNet/IP, PROFINET, Modbus TCP.