8 Replies Latest reply: Jul 17, 2008 11:47 PM by Bob_M.
Bob_M. Level 2 (295 points)
I have a Mac Pro connected to a Belkin F6C1000-TW-RK via USB. When the power fails, the computer starts to shut down and hangs. If I let it sit long enough, the computer turns itself back on before the power is restored.

I found an archived discussion (http://discussions.apple.com/thread.jspa?threadID=551180&tstart=0) that talks about Mac OS X sending a signal to UPSs to turn off its outlets after a short delay simulating a total power failure. This total power failure is what allows the "Restart after power failure" feature to work and is why the computer hangs instead of shutting down entirely when the UPS shut down script runs.

My problem with the Belkin is that the Belkin apparently never turns the power to the AC plugs off. Instead it remains on until the Mac decides power must be back and restarts. Does anyone know if the instruction sent to the UPS from Mac OS X is only compatible with APC UPSs? Or is there someway to get my Belkin UPS to behave?

Dual 2.66 Mac Pro, Mac OS X (10.5.4), Macbook, 12 inch Powerbook
  • Kappy Level 10 (266,058 points)
    You have a good question, but it's best answered by asking it of Belkin's tech support.
  • Bob_M. Level 2 (295 points)
    Actually, I wrote Belkin also, but there Mac support is very limited so I thought I would post here too, especially since I found the original discussion that pointed me in the right direction in these forums.
  • Kappy Level 10 (266,058 points)
    Well unless someone already has an answer you may find little help since whatever the problem is it is most likely related to how the UPS handles switching over when there's an outage.

    Are you using their proprietary control software or have you checked to see if you can control via Energy Saver?

    It could also be that the UPS does not handle the switchover fast enough for the computer. This is a problem with iMacs and some UPS models (even those from APC.) This is why you need to talk with Belkin.
  • Bob_M. Level 2 (295 points)
    Thanks, again.

    I am using Mac OS X's Energy Saver controls as there is no Leopard compatible software from Belkin.

    As for the switchover, that isn't the problem, it drops into battery power just fine. The issue is that once on battery power, the AC outlets should turn off, inducing a full power failure to the computer. That isn't happening.

    I have written Belkin support already and am waiting for a response. I just thought I would check here as well. I can't be the only guy with a Mac and a Belkin UPS who wants to use the Restart after Power Failure feature.
  • Kappy Level 10 (266,058 points)
    I'm afraid I'm confused. If you use the UPS to prevent loss of power during an outage why would the AC outlets be turned off? Wouldn't that defeat the whole point of a UPS? If the switchover is fast enough then the computer should not require a restart after power failure. If the computer is actually losing power before the UPS kicks on then the UPS is not switching over quickly enough which is a problem in older model UPS and models with longer kick in times.
  • Bob_M. Level 2 (295 points)
    That's all true, but UPS batteries only last so long. If the power outage is long enough, you will drain the battery. The UPS is designed to tell the computer to turn off before that happens. If you aren't concerned about getting the computer back up automatically, that works great. If you depend on remote access to your computer, however, you'd want it to be able to start back up automatically after the electricity returns.

    The problem is that the computer can only turn itself back on after a power failure, if it actually died due to the power failure. If the computer shut down normally, that's it you are done until you turn it back on manually.

    The process is this:

    1. AC Power lost
    2. UPS switches to battery power
    3. Computer tell UPS to turn off the outlets in five minutes.
    4. Computer saves/closes all work, starts shutting the OS down.
    5. Computer stalls the shut down process once all critical files and drives are secured.
    6. Computer enters a hung state and waits for the remainder of the five minutes.
    7. The UPS turns off the outlets.
    8. The computer, which is still on, dies due to a power failure with no risk to data or drives thanks to its semi-shutdown state.
    9. When the electricity comes back on, the UPS turns the outlets back on.
    10 The computer, having failed due to a power loss, is able to start back up on its own.

    The system works as advertised for APC UPSs. With the Belkin, however, the outlets were never turned off. The computer and monitor stayed on the full five to ten minutes and eventually tried to start back up with the power still out.
  • Kappy Level 10 (266,058 points)
    Gotcha. Take a look at Faronics Power Save - VersionTracker or MacUpdate software that provides more control over Energy Saver. I don't know if it will solve your problem or not but it may be cheaper than an APC UPS (which is what you should have gotten in the first place. They are excellent.)
  • Bob_M. Level 2 (295 points)
    Thanks for the reference. I didn't see the software in Version Tracker, but Google found the developer's web site. I don't know that it will help with a UPS, but I will definitely look at it for just more general control of the up and down times.

    Thanks again!