What are the key considerations for a DCS migration project?

Key considerations: migration strategy (hot cutover vs phased, parallel operation), I/O reuse (legacy I/O integration vs complete replacement), functional specification (document existing control logic, alarming, interlocks), control philosophy review (opportunity to improve), testing strategy (FAT, SAT, commissioning), operator training (HMI changes), cybersecurity requirements, and spares strategy. Risk mitigation: thorough documentation, comprehensive testing, and detailed cutover procedures. Typical challenges: undocumented modifications, custom code conversion, and change management. Budget adequate contingency for unknowns discovered during implementation.