The 6ES7322-1HH01-0AA0: Draws 100 mA from the 5 V backplane bus plus 4.5 W typical power loss. Front connector is 20-pin – not included, factor that into your BOM.
Ratings that drive the selection
Thermal continuous current per relay is 2 A. Inductive load max is 2 A, with 100 000 cycles at 230 V AC and 700 000 cycles at 120 V AC. No diagnostics, no short-circuit protection, no wire-break detection. It's a simple relay board – no fancy alarms. That means you need external fusing or a suitable load circuit if fault protection matters. Isolation tested at 1 500 V AC between channels and groups of 8. That's solid for panel separation but watch the group isolation if mixing power domains.
Where this part fits
Drops into any standard S7-300 rack – same 40 mm width, 125 mm height, 120 mm depth. No fieldbus or CPU compatibility issue; it's just a relay output slice. Unshielded cable runs up to 600 m, shielded up to 1 000 m. Connects via a 20-pin front connector (not included). Reuse the existing connector when replacing a module.