| If you need… | Consider… | |--------------|------------| | Same form‑factor | Modicon M340 or M580 (with legacy I/O adapters) | | Software compatibility | CODESYS V3 (with custom migration tool) | | Retain I/O | Use a PROFIBUS‑DP gateway to a modern PLC | | Minimal code rewrite | Siemens S7‑1500 (function block conversion utility) |