The time line shows what happens from the time the power goes out to the time the system shuts down. The duration of the time is the same as the rated life of the battery. The time line starts at the point that utility power goes off. At the same time the uninterruptible power supply or battery power unit is active. At this time user program functions (if any) and the QUPSDLYTIM value time-out is in effect. When that time expires, main storage is saved, then shut down occurs. After that there should be some time left of battery life as a safety factor.