RS-485 and signal integrity
The 6ES7288-1CR60-0AA1: The lone serial interface is RS-485 at up to 187.5 kbps — no PROFIBUS, no TCP/IP on this CPU. Shielded runs can go 500 m; unshielded, keep it under 150 m. Input thresholds: signal "0" below 5 V DC, "1" from +15 to +30 V. That 10 V deadband between 5 and 15 V is your noise margin — if you're seeing phantom bits on a long run, check the shield first. The RS-485 port is parameterizable, so you can match the baud rate to the rest of the daisy chain.
