The Siemens 6AG1241-1CH30-2XB0 is the SIPLUS version of the CM1241 RS-485 module for S7-1200, built with conformal coating and rated for -40 to 70°C ambient – so it handles condensation, temperature swings, and corrosive atmospheres that would kill a standard module. Communicates via RS-485 (X.27); Freeport is native, USS and ASCII as library functions. Power loss is 1.1 W typical, and it draws 220 mA max from the L5+ backplane – light enough that you don't need to recalc your rack budget. Maximum cable length is 1 000 m – enough for remote sensors or drives across a large plant.
Panel and wiring notes
The 30 mm width leaves DIN-rail space; the RS-485 interface supports runs up to 1 000 m. Conformal coating means you can mount it in panels without climate control, but avoid mechanical stress on the D-sub – the module is rated for 0.3 m drop five times in package, so it's not fragile, but treat the connector carefully during wiring.