The SITOP DC UPS 6EP1931-2FC42 is the most capable configuration in Siemens' standard DC UPS family: 40A output (960W) combined with a USB 2.0 interface for comprehensive PC-side monitoring and control. It provides the same industrial-grade battery backup as the 2FC21 base model while adding desktop visibility — a meaningful advantage when managing large automation systems where UPS health directly impacts production uptime.

High-Power Backup

With 22-29VDC input and 24VDC output at up to 40A continuous (42A peak), this module can buffer entire control cabinets. Its 97.2% efficiency at rated load means approximately 28.6W of heat loss — manageable with natural convection in a well-ventilated enclosure. The charging current is selectable at 1A or 2A, enabling fast recovery of battery capacity after a discharge. Switching to battery is seamless, under 1ms.

USB Monitoring and Software Integration

The USB 2.0 Full-Speed interface (Type B connector) delivers status updates every 75ms to a connected PC. After a one-time driver install, the free SITOP DC UPS Software provides real-time dashboards, historical logging, alarm notification, and remote timer-start — operators can trigger a controlled shutdown sequence from the control room. The USB link is independent of the hardwired relay contacts, which continue to signal OK/Bat, Alarm/Bat, and Battery >85% status to the local PLC.

Key Decision Parameters

Compatible battery modules from the SITOP BAT series are ordered separately. For applications not requiring PC connectivity, the 6EP1931-2FC21 offers the same 40A performance without the USB interface.