The Siemens 3RK1901-2NR12 is an AS-Interface M12 branch — a transition piece that takes the AS-i flat cable and converts it to a standard M12 connector. It's a field-mountable accessory, not a logic device: it passes the AS-i power and data signals out to a sensor or actuator via the M12 socket. The connection uses an insulation-piercing method for the flat cable, so you don't strip or cut the main trunk — just clamp it down. The branch cable is 2 meters long with an angled M12 socket on the other end. Rated for 4 A maximum contact load and 3 A operational current, it handles the typical draw of a few AS-i slaves on the drop. The operating voltage matches the AS-Interface spec: 26.5 to 31.6 V.
IP67/68/69K means this branch survives washdown, high-pressure spray, and temporary submersion. On a lube route or in a brewery, that matters — the M12 socket and the cable entry are sealed against water and dust. Ambient range of -25 to +75 °C covers most plant-floor conditions.
Mounting and wiring note
Mounts via screw fixing — no DIN rail clip. The tightening torque on the fixing screws is 1.65 N·m. The M12 socket assignment is pin 1 for ASI+ and pin 3 for ASI-. One note in the spec: the cable must not end in the feeder. That means the branch is a pass-through tap; the flat cable continues past this point to the next drop. Don't terminate the trunk here.