DescriptionThe Siemens 3RX9306-1AA00​ is an AS-Interface combi-power supply unit manufactured by Siemens, belonging to the SIRIUS / AS-i peripheral family. It integrates, in a single DIN-rail housing, a 30 V DC / 4 A AS-i bus power rail (with modulated data carried on the same yellow flat cable) and a separate 24 V DC / 5 A auxiliary output for “primary clocking” and data-decoupling reference — plus the decoupling LC network itself, so no external AS-i data decoupler is required. Input is single-phase 115 / 230 V AC switchable via a slider, making the 3RX9306-1AA00​ a drop-in, panel-space-saving brick for any AS-i master rack (SIMATIC S7-1200/1500 CM AS-i, 3RK/3RX masters, ET 200 distributed AS-i nodes).h2 Application ScenariosOn a parcel-sortation cross-belt conveyor line running 48 SIRIUS 3RA6 AS-i motor starters and ~120 IFM/Balluff AS-i sensors off a single CM 1243-2 master on S7-1200, the original panel design had a generic 30 V / 4 A AS-i PSU plus a separate data-decoupling terminal block plus a 24 V / 5 A SITOP for the primary-clock reference — three DIN bricks eating ~200 mm of rail. During a mid-life panel cleanup, the integrator replaced all three with a single Siemens 3RX9306-1AA00: the yellow AS-i flat cable passes through the built-in decoupling window on the side of the unit, the 30 V / 4 A rail feeds the AS-i backbone, and the 24 V / 5 A aux taps the same brick for the master’s primary clock. Panel width dropped by ~140 mm, wiring points fell from 14 terminals to 6, and — crucially — the 3RX9306-1AA00‘s low-output-impedance design kept Manchester signaling clean even when three starters tripped simultaneously (the ±8 V data envelope on 30 V carrier doesn’t tolerate a saggy PSU). The maintenance lead’s only complaint: “Wish we’d done this five years ago — and wish Siemens hadn’t discontinued it.” (The 3RX9306-1AA00​ is officially end-of-life; Siemens recommends replacing it with a 3RX9502-0BA00 decoupler + SITOP 6EP1333-2AA01, but for legacy panels staying “as-was,” the combi brick remains the cleanest spare to stock.)h2

Parameters

h2 Technical Principles and Innovative ValuesInnovation Point 1 – Three Devices Collapsed Into One DIN Brick. A conventional AS-i segment needs (a) a 30 V / 4 A PSU, (b) a data-decoupling terminal with ~3 300 µF electrolytic + inductor, and (c) a 24 V auxiliary for the master’s primary-clock reference. The Siemens 3RX9306-1AA00​ rolls all three into a 150-mm-wide housing. On a 20-master panel this reclaims >2 000 mm of DIN rail — real money in cabinet-build labor.Innovation Point 2 – Built-In Data Decoupling With Pass-Through Window. The yellow AS-i flat cable routes through a molded window on the side of the 3RX9306-1AA00​ that contains the decoupling LC network. No external decoupler terminal, no extra fly-leads, no “did we size the capacitor right?” guesswork. The decoupling is tuned to AS-i spec (V3.0 / V2.1 compatible), keeping the ±8 V Manchester envelope clean on the 30 V carrier even under 4 A load steps.Innovation Point 3 – Electronic Auto-Recovering Short-Circuit Limit. If a branch on the AS-i yellow cable sees a pinched conductor or a water-ingress fault, the 3RX9306-1AA00​ current-limits that branch and holds the rest of the 30 V rail up. The AS-i master can still poll and will report “slave X unreachable” rather than “bus dead.” Compare that to a dumb 30 V brick with a fuse — one branch fault =整条线 dark.Innovation Point 4 – Low Output Impedance for Signal Integrity. AS-i modulates data on the power rail; any PSU with high Zo smears the ±8 V edges and stretches bit timing. The 3RX9306-1AA00​ is specified ≤300 mV ripple on AS-i+/-, which translates to clean eye diagrams even at 4 A load. For lines pushing toward 62 slaves (AS-i V3.0 A+B addressing), that margin matters.Innovation Point 5 – Primary-Switchable Input, Global Deployment. The 115 / 230 V AC slider means the same 3RX9306-1AA00​ drops into panels in North America (120 V) and EU/Asia (230 V) without rewiring — but the slider must be set before energizing, or the primary switcher eats itself. (This is the #1 RMA cause on this SKU — more on that in Installation below.)