A model number is not enough
Replacement may involve the original program, I/O, connected drives and instruments, SCADA links and operator sequence—not just the controller hardware.
Collect the available material
Share equipment labels, source program and settings availability, drawings, I/O lists, communication links and permitted downtime.
Agree on a phased scope
Configuration review, PLC/HMI work, changeover checks and backup deliverables are defined before physical replacement.