SU RT 8000 XL - how to configure behaviour when power is lost ?

[bernd_apc]

Hi,

we have a SU RT 8000 XL and NMC AP9617 with firmware 3.7.2 (which seems to be the most recent).

Some weeks ago we had a power interruption in our building. Here are the according entries in the log:

10.08.2016	14:40:50	UPS: The output power is turned off.
10.08.2016	14:38:53	UPS: Started a reboot process.
10.08.2016	14:20:23	UPS: A graceful shutdown process is being used to shut down the load equipment before the UPS turns off. Initiated by PowerChute ns from 146.107.93.90.
10.08.2016	14:20:21	UPS: No longer on battery power.
10.08.2016	14:10:21	UPS: On battery power in response to an input power problem.

At 14:20:21 power was available again. But although power was available again, the clients (SLES 10 and SLES 11) started a shutdown just some seconds after power was restored. Why ? I expect that the clients don't shutdown when power is restored because it's not necessary any longer. Am i wrong ?
Here is my configuration of the shutdown:

Start of Shutdown
Low Battery Duration:	02 05 07 10 12 15 18 20  minutes
Shutdown Delay:	000 020 060 120 240 480 720 960  seconds
Maximum Required Delay:	15 minutes
Basic Signaling Shutdown:	Enable
Duration of Shutdown
Sleep Time:	hours [0 to 359.9]
End of Shutdown
Minimum Battery Capacity:	00 15 25 35 50 60 75 90  %
Return Delay:	000 020 060 120 240 480 720 960  seconds

I have to admit that i'm not completely familiar with this configuration.
What does "Low Battery Duration" mean ? The time that UPS can run on battery ? Or the time upon the UPS is shut down ? How can i find out that duration ?
"Shutdown Delay": help says: "Defines how long the UPS waits before it shuts down in response to a turn-off command." Where does the turn-off command come from ? Is the power loss the turn-off command ? Is it initiated by the UPS itself ? Or one of the clients ? What is shut down ? The UPS, the clients, or both ?
"Maximum Required Delay: " help says: "This delay is calculated whenever the management interface of the UPS turns on or is reset, or when "Force Negotiation" is selected as Maximum Required Delay. "Force Negotiation" polls each client for information on the time it needs for a graceful shutdown." I find "Force Neotiation" in "Power Chtue ==> configuration". Calculation needs just 1 - 2 sec. Is that right ? Help says it can take up to 10 minutes.
Where can i configure "x min after power loss shut down the clients" ? Is that the "Shutdown Delay" ? Or is it configured in the web interface of the clients ?

Thanks.

Bernd

[BillP · Accepted solution]

Hi Bernd, 

What I believe happened in your situation was that PCNS sent a shutdown command to your clients just before, or at the time power was restored, and once a command is sent, even when power restores immediately after, the clients will continue to shutdown. 

What we can do is change your settings to hopefully avoid this in the future. Please see my answers to your questions below:

The "Low Battery Duration" is the time at which the UPS will start a shut down depending on the amount of runtime you have left. So in your situation, the UPS will send a shutdown command when there is 15 mins left of runtime on battery. 

The turn-off command comes from the low battery duration. So once you reach 15 mins left of runtime, the command is sent. This is a global command, so it will be sent to all PowerChute clients, and once those clients are shut down, the UPS itself will turn off. Right now your shutdown delay is set to 120 seconds. So once you reach 15 mins of runtime, the UPS will send a shutdown command to the PCNS clients, wait 120 seconds for them to shut off, then shut itself down. 

For the Force Negotiation, the time it takes to calculate the Maximum Required Delay depends on how many PowerChute clients you have. It has to poll each of them individually which is why it may take up to 10 mins max if you have a lot of clients. Since you only have 2 clients, the calculation should not take very long. 

As for configuring "x min after power loss shut down the clients", that can be done in the PCNS interface for the clients. 

Let me know if you have any further questions. 

Nicole