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Discussion Starter · #1 ·
In the BIOS of my HTPC, I have it set to automatically restart the computer after a power loss. However I also have the HTPC on a UPS, which will execute a controlled shutdown of the PC when there is 5 minutes of battery power remaining.


Problem: I was recently traveling on an extended overseas business trip. There was a lengthy power outage at my home, so the UPS ran down and shut off the PC in an orderly manner. When the power came back on, the PC did not restart.


Ideas or suggestions on why not? I missed several TV show recordings in Media Center, and my home automation system also stopped working. The loss of home automation was a problem for my wife, who had to go around and put all the lamps on standard outlets because she didn't know why the automation system wasn't working. When I go home, all that needed to be done was to turn the HTPC back on, but she didn't know that and didn't want to bother me with troubleshooting while I was traveling.
 

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It's probably because the UPS never actually ran out of power, since the PC shut down the power draw dropped so the UPS managed to provide power to the PC for the whole outage and thus the PC didn't see the power ever go off.


On my APC UPS, there's an option in the UPS settings for it to cycle power thus causing a PC configured that way to turn on when power is restored.
 

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Discussion Starter · #3 ·
Thanks I will look for that power cycling option in my APC software. I don't recall seeing it so maybe I need to update.


Thanks again for the reply.
 

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This can be difficult, depending on the UPS you have and the software you use. What you need to do is send a signal to the UPS to cut the power, but you obviously can't do that once the OS has shut down. As such, you need a UPS that supports delayed shutdown signals so that the PC can tell the UPS to shut down in x minutes, where x is a duration longer than it takes for the PC to hibernate.


Most business-class UPSes support this, but residential-level ones often either don't support it at all or have a fixed delay of some arbitrary number of minutes (e.g. 2). The biggest risk with such a system is that if some program on your PC stops responding and blocks the shutdown, the UPS will cut the power too soon and your PC won't shut down cleanly. If you have your BIOS set to automatically boot the PC when it detects power, though, it will restart as soon as the power comes back. You may need to research your particular UPS to determine the types of shutdown signals it supports.
 

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Discussion Starter · #5 ·
I appreciate your detailed response, Aleron - thank you.


I am using an APC UPS with the PowerChute Personal Edition software. I downloaded the latest version but I could not find any option for instructing the UPS to cycle power to the load once the mains power is restored.


I went into my BIOS to verify settings and I was surprised to find that the Power On upon detection of AC Power was set to Power Off. I can't understand that since it was set to power on previously. In any case, I set it to Power On so we'll see if I run into this issue next time. I might pull the plug on the UPS and let it run down, just to see what happens.
 

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The problem with that approach is that it will only work if the outage lasts longer than the duration of your battery. If the power returns before your battery discharges, the UPS won't cut the power to your PC, so the PC won't restart when the utility power returns. You also can't rely on the battery to drain fully if the PC is set to shut down automatically, since the battery will drain much more slowly once the PC is off (unless you attach some other device to the UPS).
 

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I won't be able to help you with APC but with CyberPower I didn't have that option in the personal edition software. Downloaded the business edition for free and I had that option. Not as good looking or easy to use but a ton more options. Maybe APC has a similar option.
 

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Discussion Starter · #8 ·
Upon further research, I believe that the behavior of the consumer-grade APC UPS is as follows:


1. Power is lost.

2. UPS keeps supplying power to load (computer).

3. At the power reserve setting specified in the PowerChute Personal Edition software, for example 5%, the software initiates an orderly shutdown of the PC.

4. The UPS then disconnects the load and goes into a power-saving mode.

5. Upon restoration of power, the UPS recharges its battery and re-connects the load to the inverter output.


Therefore, the PC should restart if the BIOS is set to "Always On" / "Power On" or even "Last State" if the PC was left running.


I think my problem was that the BIOS (somehow) was set to Power Off and so the PC never rebooted when the power came back.

Here is some additional information from Schneider Electric.
 

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"Always Off" and "Last State" won't work in this scenario, but "Always On" should work.


Since the PC was shut down by the UPS, power wasn't lost the way the PC sees it. It was simply shutdown by a process (in this case the UPS, but usually a user would do this manually).


Last State only works if the PC was actually on when it lost power, since it was shut down (and didn't actually lose power when it was running) that option won't power it back up; if it was off (which it would be if the UPS shut it down) then it will stay off.


The only option that will turn the PC on in this case is the "Always On" (could also be called "Power On" as you indicate) option. What this does is, regardless of whether the PC was on or off and regardless of what was going on when the power was disconnected, it will turn on whenever you connect the AC cord (or when you flip the switch on the PSU, if equipped). Note that some BIOSes don't actually work as intended due to bugs or PSU differences, so you should try this out yourself first. Have the computer on/running and idle and then either switch the PSU off or remove the power cable. Wait a minute or so and then reconnect it (or turn the PSU back on) and see if it powers up. If it doesn't, it probably won't work in your scenario either--you might need to get a BIOS update from the manufacturer or a different motherboard that actually works properly with this feature.
 

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Discussion Starter · #10 ·
I did some testing:
  • I set the UPS software to "Preserve Battery Power" and shut down the PC after one minute of AC power loss.
  • I pulled the UPS power cord out of the wall socket.
  • To my surprise, the software doesn't shut down the PC...it puts it into Hibernation mode.
  • Upon plugging the UPS back into the outlet...nothing. The PC did not restart.
  • I unplugged the PC cord from the UPS.
  • When I plugged it back in, the PC started - or rather, it came out of Hibernation.


So apparently the UPS does keep some juice applied to the PC, even after it shuts down the PC. Therefore the PC never sees a change in power state and will not wake itself up.
 

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Quote:
Originally Posted by HMenke  /t/1523586/automatically-restart-htpc-after-ups-controlled-shutdown#post_24516497


To my surprise, the software doesn't shut down the PC...it puts it into Hibernation mode.
Yes, PowerChute Personal Edition always works that way.
Quote:
So apparently the UPS does keep some juice applied to the PC, even after it shuts down the PC. Therefore the PC never sees a change in power state and will not wake itself up.

That's why I said you need to send the shutdown command to the UPS. The UPS doesn't turn off when you shut down the PC and will continue supplying standby power to it for the duration of the outage. The only things that cause the UPS to stop supplying power are exhausting the battery, telling it to turn off, and pressing the power button.
 

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Quote:
Originally Posted by HMenke  /t/1523586/automatically-restart-htpc-after-ups-controlled-shutdown#post_24516497


I did some testing:
  • I set the UPS software to "Preserve Battery Power" and shut down the PC after one minute of AC power loss.
  • I pulled the UPS power cord out of the wall socket.
  • To my surprise, the software doesn't shut down the PC...it puts it into Hibernation mode.
  • Upon plugging the UPS back into the outlet...nothing. The PC did not restart.
  • I unplugged the PC cord from the UPS.
  • When I plugged it back in, the PC started - or rather, it came out of Hibernation.


So apparently the UPS does keep some juice applied to the PC, even after it shuts down the PC. Therefore the PC never sees a change in power state and will not wake itself up.
Interesting...so the UPS is never running down completely, probably since once the PC is shut down there is very little power draw and the battery can last quite a while before going dead. In that case, if the UPS can power down (hibernate) the PC, can't it be set to wake the PC once it gets AC power again?
 

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Discussion Starter · #13 ·
Apparently the UPS I'm using is too basic and doesn't have any facility for shutting itself down (or, interrupting power to the load side) nor does it have the ability to send a wake up command to the PC.


These things seem pretty straightforward, so I plan to do some research on which consumer-grade UPS I can upgrade to that will allow more elaborate power management strategies.
 

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You won't be able to stick with APC if you want that functionality. Only the exorbitantly priced SmartUPS series has those features, IIRC. The Back-UPS RS models have no grace period and will instantly die when you issue the command to cut the power, while the CS and ES models have a fixed grace period of two minutes (meaning if your PC needs longer than that to shut down, the UPS will just cut the power anyway while your PC is still on).


Is it really that hard to tell your wife to just press the power button on the PC after an extended outage to restore your home automation functions? The fact that you want the PC to automatically restart itself suggests that it won't require any user intervention once power is restored for it to resume its usual functions.
 

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Quote:
Originally Posted by HMenke  /t/1523586/automatically-restart-htpc-after-ups-controlled-shutdown#post_24519688


Apparently the UPS I'm using is too basic and doesn't have any facility for shutting itself down (or, interrupting power to the load side) nor does it have the ability to send a wake up command to the PC.


These things seem pretty straightforward, so I plan to do some research on which consumer-grade UPS I can upgrade to that will allow more elaborate power management strategies.

I bought the CyberPower 1000PFCLCD and it has all the features you're looking for. I used the Business edition software because I have my server hooked up to it as well and I can shut it off to without having it connected to the UPS with a USB.


Once the power dies the 2 PCs go to battery. The server is set to shut off once battery gets to 10 minutes and the workstation shuts off at 5 minutes left. Once the power returns the UPS restarts itself, the PCs see that and turn back on. All without any outside intervention.
 

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Discussion Starter · #16 ·

Quote:
Originally Posted by Aleron Ives  /t/1523586/automatically-restart-htpc-after-ups-controlled-shutdown#post_24520166


Is it really that hard to tell your wife to just press the power button on the PC after an extended outage to restore your home automation functions?

She's not the biggest fan of home automation to begin with. In any case, is it really automated if it requires manual intervention to function reliably? What if we are on vacation and want to ensure that the vacation modes remain operational?
Quote:
Originally Posted by Aleron Ives  /t/1523586/automatically-restart-htpc-after-ups-controlled-shutdown#post_24520166


The fact that you want the PC to automatically restart itself suggests that it won't require any user intervention once power is restored for it to resume its usual functions.

This is the case. Everything I need to be operational for home automation and DVR functionality runs as a service.
 

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Discussion Starter · #17 ·

Quote:
Originally Posted by JackDiesel14  /t/1523586/automatically-restart-htpc-after-ups-controlled-shutdown#post_24520218


I bought the CyberPower 1000PFCLCD and it has all the features you're looking for. I used the Business edition software because I have my server hooked up to it as well and I can shut it off too without having it connected to the UPS with a USB.

Thanks Jack! I will have a look at this option.



In the realm of DIY hacker solutions, I'm wondering if this 5V USB-controlled switched outlet could be a workable $30 solution.




The switched outlet drops out when 5V disappears from the USB port. The trick is finding or creating a 5V source that remains on long enough for an orderly PC shut down, then goes away to shut off the switched outlet, then returns when AC power is restored to close the switched outlet, sending AC to the PC and allow it to automatically restart.
 

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Discussion Starter · #18 ·
Jack, I downloaded and installed the CyberPower PowerPanel Personal Edition Software. Of course it didn't fund a connected UPS, so perhaps it was not showing all the features, but I did npt see any menu items for controlling restart behavior. Can you describe these features in more detail? Also I don't really need a UPS with that much VA/runtime. I wonder if any smaller units have the same functionality.
 

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Discussion Starter · #19 ·
I found some screen shots indicating an Energy Management feature in the PowerChute Personal Edition software:






However I don't see this option in my software. I'm guessing it is UPS model-dependent as far as what features you may have or not have. The article where I found the images was based on an APC Back-UPS ES-550, which is the same model I have, but perhaps mine is an earlier version.
 

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Discussion Starter · #20 ·
The clouds are lifting on the APC PowerChute feature mystery. It looks like there is a Power Saving feature that is part of the UPS which is intended to shut off peripherals when the PC is off or hibernating. Despite that the article referenced above claimed to have been using a Back-UPS ES 550, the Energy Saving functionality is not available unless you step up to the BE750G .


You can recognize the feature by looking at the UPS and taking note of the "Master" and "Controlled by Master" labels on the various outlets:




My lowly ES 550 (a.k.a. BE550G ) has no such designations:

 
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