The SITOP PSE200U selectivity module and the SITOP select diagnostic module provide selective protection for individual 24-V paths against overload and short circuits. The buffer module bridges short-term power outages of up to 3 seconds using capacitors as energy storage. The signaling module with signal contacts and remote ON/OFF function integrates SITOP modular (devices without integrated signaling contacts) optimally into automated systems. For maximum availability, the redundancy module SITOP PSE202U decouples identical SITOP power supplies.