What this SIRIUS motor starter does on an AS-Interface line
The Siemens 3RK4320-3CQ54-0BA2 is a SIRIUS MCU motor starter designed as a direct starter for AS-Interface networks — it integrates the motor protection, switching, and fieldbus communication into one unit that bolts onto a vertical mounting surface.
AS-Interface integration and I/O count
Two onboard digital inputs let the starter pick up local limit switches or pushbuttons without a separate I/O block — the AS-Interface protocol carries the status and control words back to the PLC over the yellow flat cable. The control supply is 20.4–26.4 V DC, which matches the AS-Interface bus power rail — no separate 24 V supply needed for the electronics.
Mounting and environmental fit
At 205 mm deep, 245 mm wide, and 215 mm tall, this starter takes up a panel footprint comparable to a small contactor-and-overload combo — plan the DIN-rail or screw-mount layout accordingly. IP54 means it's protected against dust ingress and splashing water — fine for most control cabinets, but not for washdown zones. Ambient operating range is -25 to +50 °C, covering most indoor industrial environments without derating.