The Siemens 3RK1200-0CT20-0AA3 is a K45 compact digital I/O module for AS-Interface fieldbus networks, providing 4 PNP inputs in a sealed IP67 housing. It draws power directly from the AS-Interface cable, so no separate 24 V supply is needed at the module — the yellow flat cable carries both data and power. The module is designed for standard rail mounting or wall mounting via a K45 mounting plate, and the front addressing socket lets you set the slave address with a standard AS-Interface hand-held programmer.
The 4 inputs are PNP (sourcing) type, switching at a minimum high-level threshold of 10 V, with a signal current of at least 6 mA at logic 1 and under 1.5 mA at logic 0. The sensor supply on PIN 1 (L+) and PIN 3 (L-) is short-circuit and overload protected, so a shorted sensor lead won't take down the entire AS-Interface segment. Total current draw from the AS-Interface bus is capped at 270 mA at 40 °C ambient, which includes both module electronics and the sensor supply current — budget accordingly when calculating segment load. IP67 protection means the module and its M12-style sockets survive washdown, dust, and condensation — suitable for mounting directly on a conveyor frame or machine base in food, beverage, or automotive assembly lines.
Integration notes
Each of the four M12 sockets maps PIN 4 to a data input (D0 through D3). The yellow LED per input shows the switching state; the green/red dual LED on the front indicates AS-Interface communication and diagnostics. Modules are delivered without a mounting plate — order the K45 mounting plate separately if wall-mounting.