What this CPU delivers on a high-speed line
The Siemens 6ES7288-1SR20-0AA1 is an S7-1200 CPU that packs 12 kbyte of program memory and a 144-byte I/O image (256 bits digital plus 56 words analog each way) into a 90 x 100 x 81 mm DIN-rail footprint. It runs LAD, FBD, or STL, and the minimum PROFINET update time is 4 ms — that 4 ms is the cycle floor for deterministic IO exchange, so it holds takt time on a body-shop weld line where every millisecond counts. The RTC keeps time for 7 days without battery backup, which means a power loss over a long weekend loses the clock; plan for a time-sync at startup if your process timestamps matter.
IO and fieldbus — what connects where
Built-in RS485 runs at up to 187.5 kbps, shielded max 500 m. PROFIBUS is available via a CM DP module, not on-board. PROFINET IO with autocrossing and autonegotiation handles up to 128 bytes input and 128 bytes output per device. The CPU supports both client and server roles. For high-speed counting, six single-phase HSCs are configurable: four at 200 kHz and two at 30 kHz; in A/B phase mode, two at 100 kHz and two at 20 kHz. That covers encoder feedback for conveyor positioning without an extra module.
Transformer-isolated power supply with 1500 V AC isolation, accepting 120 V AC or 230 V AC. CE marked. No UL or CSA listing in the record; confirm with your local inspector if the job requires it.