What this M12 branch does
The 3RK1901-1NR20 is an AS-Interface flat-cable transition to an M12 socket — it taps the AS-i bus (26.5–31.6 V) and the auxiliary power (Uaux) from the flat cable and brings them out to a single M12 female connector. Pinout is fixed: pin 1 = AS-i +, pin 2 = Uaux –, pin 3 = AS-i –, pin 4 = Uaux +. That means a standard M12 cordset gives you both the bus signal and a separate 24 V auxiliary supply in one connector — no need for a second drop.
IP rating and mounting reality
Rated IP67/68/69K — the housing and the M12 socket withstand high-pressure washdown and temporary submersion, so it fits food-and-bev, washdown, or outdoor conveyor lines where a standard IP67 module would fail under a hose-down cycle. Mounts with screw fixing, not DIN-rail snap-on. Plan for a drilled panel or bracket — the flat cable runs through the insulation-piercing gland, and the branch body bolts down.
Current and temperature limits
Contacts rated 4 A max — enough for a small actuator or sensor cluster on the auxiliary supply, but not for a motor or heater load. The branch is a signal-and-power tap, not a power distribution block. Ambient operating range –25 to +75 °C, storage –25 to +85 °C.