This page shows the status of an UPS in my network.
You can hover over the labels to get more information.
It updates every 30 seconds.
If you're interested in historical data, I have another UPS that logs this.
This is an on-line UPS. This type of UPS always filters the power through the rectifier and inverter as seen in the graph. This provides a smoother output compared to a line-interactive UPS (the more common but chaper type). They protect better against fast power spikes caused by lightning strike because no mechanical switching to disconnect the mains lines is necessary. This guarantees that the UPS will take the impact of problems on the power grid, but this is the preferable option compared to having the connected equipment getting damaged. An additional advantage is that they're suitable to be connected to power generators that outout "dirty" AC.
In case you're wondering, the UPS model is a PowerWalker VFI 1000 TG and is very affordable. Be careful before you buy this. This is for 230 Volt applications, not 110 Volts. I verified with my scope that it outputs a pure sine wave. The software to control it is a bit weird to use and definietly has been translated by some automated mechanism in some places.