PLC FAT and SAT checklist: test behavior and handover evidence
Plan factory and site acceptance around requirements, observable results, failure states, approved changes and recoverable project files.
Tag-based addressing
Named variables vs fixed addresses.
Modern PLC style: symbols like Line1_Mixer_Speed instead of fixed register numbers. Self-documenting and refactorable; gateways map tags to Modbus or OPC UA addresses at the boundary.
Use the concept: 4–20 mA loop scaling · Industrial automation fundamentals · Modbus RTU CRC & frame helper
In depth
PLC analog input scaling: raw counts, 4–20 mA and diagnostics
Map raw counts into engineering units, check the configured channel range, and keep signal-quality diagnostics separate from the displayed value.
OT backup and restore testing: prove the recovery path
Inventory the files and dependencies needed to recover a control system, set recovery objectives, and test restoration on an isolated target.