What this module is and why you’d grab it
The 6AG1221-1BH30-4XB0: Draws 2.5 W typ from the backplane, 130 mA at 5 V DC. Low enough to fit on a crowded S7-1200 rack without worrying about power budget.
How it stacks against the 6AG1223 combi modules
This is pure 16 DI — no outputs. The 6AG1223-1PL32-4XB0 is a combi module, different footprint and wiring.
Lifecycle and sourcing reality
CE marked, FM approved. Clean compliance doc trail.
Mounting and wiring notes
45 x 100 x 75 mm, IP20 plastic housing. Front connector required (sold separately). Shielded cable max 500 m, unshielded 300 m. Signal thresholds: 15 V DC at 2.5 mA for "1", 5 V DC at 1 mA for "0". Groups of 4 for channel isolation.