The invention relates to an arrangement for an uninterruptible power supply with a rectifier, an energy store, an inverter, a switching means and a controller. The rectifier is connected to a rectifier input to a supply grid (AC1). The energy store is connected to a rectifier output of the rectifier (1) and to an inverter input of the inverter. A network (AC3) to be protected or a load to be protected is connected to an inverter output of the inverter, wherein the rectifier input or a supply grid (AC2) is connected via the switching means to the inverter output, and wherein the rectifier, the inverter and the switching means is controlled by the controller, wherein the controller has two control parts which are constructed with redundancy, and wherein the rectifier and the switching means or the inverter and the switching means can be controlled simultaneously by the control parts.