Siemens's Industry Automation Division has developed two 3-phase, 24 volt power supplies: the Sitop PSU300P and the Simatic ET200pro PS. These primary switched-mode 8 amp power supplies have the IP65 degree of protection, and have been designed for distributed use directly in electrical installations. Sitop PSU300P is suitable for universal applications, whereas the Simatic ET200pro PS has been specifically designed for the Simatic ET200pro distributed I/O system, and supplies the electronic and load voltages to its system components. This power supply also has a special connector for looping through a 3-phase 380–480 AC voltage. Both power supplies are suitable for use in ambient temperatures ranging between minus 25 and plus 55 degrees Celsius.

Both the Sitop PSU300P and the Simatic ET200pro PS are simply plugged into the mains supply. They are mounted either on a Simatic ET200pro system rail, or just with nuts and bolts. Their rugged construction enables them to be mounted in any position. The operating status "DC 24 volt OK" is indicated by an LED, and output via a signaling contact. A second signaling contact indicates an overtemperature to enable countermeasures to be taken in good time, for example by a higher-level control. The 24 volt output is no-load and short-circuit-proof, and is electronically adjusted down during overload.

The power supplies have Sitop UPS500P uninterruptible power supply (UPS) modules for bridging power failures. These are based on maintenance-free capacitor technology, and also have the IP65 degree of protection. Coupled with the new power supplies they give users the complete solution for an uninterruptible, distributed 24 volt power supply.