The Siemens 6EP1961-2BA00 is a SITOP buffer module that bridges brief mains dips, keeping a 24 V DC control bus alive when the primary supply drops. It delivers four individually fused outputs, each protected by a 15 A blade-type fuse included at delivery. Rated efficiency of 97 % means the module loses very little energy as heat — important when it's packed into a small enclosure with other heat-generating gear. The output voltage follows the formula Vin - approx. 0.3 V, so the load sees nearly the same voltage as the input bus, just a diode drop lower.
The module accepts an input voltage range of 22... 30 V DC, which covers the nominal 24 V bus and allows for some sag or overvoltage during charging. On the output side, four screw terminals (each accepting 0.22... 4 mm²) connect the loads. The simultaneous connection of all outputs after power-up is the default behavior, with a delay time of 24 ms or 100 ms programmable for sequential connection — useful when you need to stagger the startup of multiple drives or PLC racks to avoid a collective inrush surge. Overcurrent protection is staged: for a sustained overload of 1.0... 1.3 x set value, the module switches off after approx. 5 s. For a hard short (1.3 x set value), it switches off after approx. 50... 100 ms. An immediate switch-off (approx. 0.5 ms) triggers when output current exceeds the set value and input voltage drops below 20 V — this catches a dead-short condition on the bus before the fuse blows. The enclosure measures 72 mm wide, 90 mm deep, and 90 mm high, fitting a standard 190 mm mounting height on the DIN rail.
The module carries CE marking, EAC approval, and UL recognition: UL-Recognized (UL 2367) File E328600 and cULus-Listed (UL 508, CSA C22.2 No. 107.1) File E197259. Safety is designed to EN 60950-1 and EN 50178. For EMC, emitted interference meets EN 55022 Class B, and immunity meets EN 61000-6-2 — so it's suitable for residential and light-industrial environments without additional filtering.
Sourcing and Integration Reality
For a panel OEM or MRO planner, the 72 mm width and DIN-rail snap-on mean it occupies one standard module slot.