FAT: review what can be proved before shipment
Agree drawings, instruments, IO/interface definitions, expected states, alarms, operator authority and backup handling. Use simulated signals only where the test record explicitly identifies them. A simulation can check logic behavior but cannot prove actual product handling, cleaning coverage or installed utilities.
SAT: test the real connections and conditions
Inspect the installed material/utility paths, instrument calibration and machine interfaces. Run agreed product and disturbance cases with the responsible specialists. Record accepted output and quality over a representative period, including identified startup, stop and recovery boundaries.
Close deviations and transfer responsibility
Give each deviation an owner, resolution and repeat-test requirement. Hand over final drawings, configuration backups, training and validation records within the agreed scope. Do not report acceptance as complete while an unresolved item affects the intended production or cleaning boundary.
