Function & operation
The SM 1223 sits on the S7-1200 G2 backplane and extends the CPU's local I/O count. The 8 digital inputs accept 24 V DC signals from proximity sensors, limit switches or pushbuttons; the 8 relay outputs switch up to 2 A for contactors, solenoid valves or indicator lamps. Relay outputs provide isolated switching for mixed-voltage loads and simplify wiring when the load side runs a different supply than the 24 V DC input side. The 2 A per channel rating covers most pilot-duty and small-motor loads within a control cabinet.
Applications
Digital I/O modules of this class are used in machine control, conveyor systems, packaging equipment and building automation to connect discrete sensors and actuators to the PLC backplane.
Lifecycle & availability
Siemens lists the 6ES7223-5PH50-0XB0 as an active product, meaning it is in current production and available through standard distribution channels without last-time-buy constraints. RoHS compliance was established as of 22-01-25, confirming the module meets the EU Restriction of Hazardous Substances directive for new installations.