The EIB / KNX Uninterruptible Power Supply SU/S 30.640.1 permanently monitors the KNX, the mains voltage, and the battery voltage.
During a fault, the green ON LED on the SU/S goes off. The cause of the fault is shown by the LEDs directly on the device and passed along via the floating changeover contact.
In order to transmit the error message on the KNX, you can connect a binary input to this changeover contact.
The alarm stays saved on the device until the fault has been acknowledged on the SU/S 30.640.1 itself through the reset button.