smart ups SMT 750i - no reboot after outlet power is restored

[Anonymous user]

We are trying to control a single PC using a SmartUPS SMT 750i. The PC is the only device connected to the USV (power cable and via usb for communication).

Everytime the outlet power fails, the PC should shutdown gracefully and when power is restored it is supposed to boot up again. (OS is Windows 7)

There are 2 special cases:

1) If outlet power fails during the boot process the computer is supposed to boot up and immediately shutdown again.

2) If outlet power is restored during shutdown the computer is supposed to finish the shutdown process and boot up again immediately.

Special case 2 is not working.

Scenario 2) (not working):
(outlet power fails) -> (UPS goes on battery) -> (windows is shutting down) -> (outlet power is restored) -> (windows finishes shutdown) -> (UPS cuts power (4s.) ) -> (UPS turns the power on again) -> (PC is not booting up)

Default Scenario (working):
(outlet power fails) -> (UPS goes on battery) -> (windows is shutting down) -> (windows finishes shutdown) -> (UPS cuts power (4s.) ) -> (UPS enters sleep mode) -> (outlet power is restored) -> (PC is booting up)

We are not sure why the default scenario does work, but in case 2) where the power is restored too early, the computer doesn't boot up. Power is cut off in both cases for at least 4s.

The BIOS options we've set are
"Restore AC Power Loss: Power On"
"Enable ACPI Auto Configuration: Enabled"
"Wake Up On USB: Enabled"

USB communication seems to be irrelevant for powering on the pc. We tried to remove the USB cable after a successful shutdown and the results were the same.

We suppose that the problem is related to:
http://nam-en.apc.com/app/answers/detail/a_id/2929

Software we use: Power chute business edition, 9.0.1
Firmware Revision UPS 05.0 / COM 02.1

The next step we plan to do is installing a firmware update (to COM 03.1). We are not sure, if the problem is directly related to the UPS or to the power management settings of the PC.

Thank you for any advice!

Message was edited by: ivo_c