The Siemens 3RK2100-1EQ20-0AA3 is an AS-Interface K45 compact digital output module that lives right out on the machine frame, not tucked away in a cabinet. It gives you three PNP transistor outputs, each rated at 3 A max, and it's sealed to IP67 so it can take the washdown and grit you'd find on a conveyor line or a packaging station. One thing that'll trip you up if you're not watching: this module needs an external auxiliary supply (AUX POWER) of 20 to 30 V DC to run the output circuits, and that supply has to meet VDE 0106 (PELV), protection class III. The AS-Interface bus cable alone won't power the outputs — you're running a separate 24 V DC feed through the black flat cable.
Ratings that matter on the route
Each of the three outputs can handle up to 3 A, but that's at 40 °C ambient — at 200 mA per channel if you're running them hot in a panel or near a motor. The module draws 45 mA from the AS-Interface bus for its own logic, and the outputs are PNP — common-sourcing positive. Each M12 socket maps pin 4 to an output (OUT1, OUT2, OUT3), with pin 3 as common negative and pin 5 as the ground terminal. You can use 2- or 3-wire sensors on the input side if you ever need to expand, though this variant has no digital inputs.
The footprint is compact at 45 mm wide, 80 mm tall, and 30 mm deep — about the size of a fat relay, so it won't eat up real estate in a junction box. Addressing is done through the front socket, and the module operates as an A/B slave with ID/ID2 code A/0. Status LEDs on the front tell you what's happening: yellow for each output, green for auxiliary power, and a dual red/green LED for AS-Interface bus and diagnostics. There's also a built-in watchdog that'll drop the outputs if the bus communication fails.