CPU 224 compact unit — AC supply, 14 inputs, 10 relay outputs
The Siemens 6ES7214-1BD21-0XB0 is a SIMATIC S7-200 CPU 224 compact unit with an AC power supply, 14 digital inputs (DC) and 10 relay outputs, 8 KB code memory and 5 KB data memory, extendable via Profibus DP. The 14 DC-sinking inputs and 10 relay outputs cover the I/O count for a medium-sized standalone machine or a remote I/O node on a Profibus DP network — the relay outputs handle up to 2 A per channel for solenoid valves, contactor coils, or indicator lamps without an interposing relay.
Memory, expansion, and fieldbus integration
With 8 KB of code memory and 5 KB of data memory, the CPU 224 runs a moderate-size control program — ladder logic for a pick-and-place cell or a small conveyor system fits within this footprint. The Profibus DP extension allows the CPU 224 to act as a DP slave on a higher-level network, exchanging I/O data with a master PLC or SCADA system without adding a separate gateway module.