The SITOP PSE201U 6EP1961-3BA01 is Siemens' capacitor-based buffer module, providing maintenance-free short-term power bridging for 24VDC systems during mains failures lasting from 200ms up to 10 seconds.

Core Function

Connected in parallel with the 24VDC bus, the module charges its internal capacitor bank during normal operation. When the input voltage drops below 22.5VDC during a mains failure, the module instantly discharges stored energy to maintain the 24VDC bus. This bridges short interruptions and provides controlled shutdown time for PLCs, drives, and industrial PCs to save process data before power is lost.

Buffer Performance

At 40A full load, the module bridges 200ms. At 20A, 400ms. At 5A, 1.6 seconds. Up to 8 modules can be paralleled for a maximum buffer time of 10 seconds. Unlike battery-based UPS systems, the capacitor storage requires no periodic replacement, no maintenance, and operates across a wide temperature range.

Installation

Snap-on 35mm DIN rail mounting in a 70mm-wide housing. Screw terminals accept 0.5-10mm wiring. A green LED indicates when the supply voltage exceeds 20.5VDC. ATEX (II 3G Ex nA nC IIC T4 Gc) and marine certifications (ABS, DNV) extend deployment options.