Had to replace the AC-EMWIN system UPS. Past couple days it started acting squirrley. Would have some sort of hiccup which caused it to beep endlessly in one long, unending tone. When I'd go into the room to check, I'd find the red light flashing, and the desktop would be blank - no EMWIN software running.
I'd reset the battery. Red light would keep flashing. I'd turn the battery off and then back on. Wouldn't do anything. Unplugged it for a while. Didn't help, either. Left it alone and restarted the EMWIN software and let it be, to see what would happen.
In subsequent days, same thing would happen. Sometimes, after a while, the battery light would go green again, BUT, I'd find all the EMWIN software unloaded again, and a naked desktop (i.e., just the normal icons and folders, with no programs running), as if the system had been rebooted. Odd.
So, the battery was apparently having some kind of hiccup wherein it would shut down all the software that was running, shut down the computer, and then restart the computer. But in the occasions where it would reboot the computer, there would be no warning. No beep, nothing. AND, mysteriously, you'd find the battery light lit green.
This was not acceptable and obviously the battery was in a non-relilable state so I went out and purchased a new one.
The system is again operating normally.