The Siemens 3RK1904-2AB01 is a handheld AS-Interface addressing and diagnostic unit for active AS-i modules and intelligent sensors/actuators compliant with AS-Interface specification V2.1. It connects to the target device through an M12 socket with a defined pinout: Pin 1 carries AS-i+, Pin 3 carries AS-i-/GND, and Pins 2, 4, and 5 are reserved for IR addressing. Power comes from four LR6 (NEDA 15) batteries, good for at least 2500 device addressings per set; the unit auto-powers off about one minute after the last operation to conserve battery life.
The IP50 rating means the housing is dust-protected but not sealed against water — this is strictly an indoor tool for dry environments like control cabinets or commissioning benches. Operating temperature range of 0 to 55 °C covers most plant-floor conditions; storage range of -20 to +55 °C (without batteries) is fine for the service van between jobs. The 100 mA rated operational current is the unit's own draw during addressing — negligible for the battery budget, but it tells you the M12 connection isn't powering anything else.