PCBE v9.0 - Durations and Sequence

[Anonymous user]

Hello!

There certainly seems to be no shortage of confusion regarding durations, sequences, etc. 🙂

I think it would be a great idea for APC to develop a whitepaper to spell it all out clearly - with very detailed descriptions, and example scenarios to help illustrate various shutdown conditions and sequences. It seems to me it could save you (APC) some considerable support resources, since these questions keep recurring. I "spoke" with an APC on-line chat technician this morning, and the answers I got seemed to be contradictory to what I have observed through some experimentation. The technician was certainly trying to be helpful - no complaints there. But I'm just not 100% convinced that the information was accurate.

I've reviewed as many of the pertinent threads I can find, relating to this topic, but none of them seem to cover exactly what I need to know. Some come close, but they don't quite hit the bulls eye. So, here I go ...



Here are some parameters for my scenario:

Assume that the Server Shutdown - Shutdown Settings - OS Shutdown Duration is set for 10 minutes.


Assume that the Server Shutdown - Shutdown Settings also include a Command File which has a duration of 3 minutes defined.


Assume that the Events - Actions - Time On Battery Threshold Exceeded has a duration of 5 minutes, and is configured to initiate a Shutdown Sequence.



Now, when a power event occurs (i.e. the mains power is lost), I think the UPS should switch to battery and:

1) Run on battery for 5 minutes ... then trigger a shutdown sequence. +(This would be the 5 minute duration defined in the Time On Battery Threshold Exceeded event.)+



2) The triggering of the shutdown sequence will cause the Command File to run, and that command file will be given 3 minutes to complete. +(This would be based on defining the Command File and the corresponding duration in the Shutdown Settings area.)+



3) At that point, the UPS will having been running on battery for 8 minutes (5 minutes of On-Battery-Threshold + 3 minutes for the command file); then, an actual O/S shutdown will begin ... and simultaneously, the UPS itself will be sent a command to begin its internal count down timer (based on the OS Shutdown Duration - in our case, a setting of 10 minutes).


4) After 10 minutes +(from the OS Shutdown Duration)+, the UPS will turn off power to its outlets and will shut itself off.


Can anyone (from APC???) confirm that my understanding of this is correct? Oh, by the way ... all of these references are to the web interface. We just need to control a single node, so I have only installed the v9.0 Agent - no need for the Server or Consol components in this case.


I also have a few other questions ...

What is the purpose of the user-settable Runtime Remaining Threshold value which can be found under Server Shutdown - Shutown Settings? It seems to me, that this should be a calculated value (eg. 18 minutes in the above scenario). Why let the user set this value? What is the effect of setting that value to something that is "too small" (eg. 10 or 15 minutes, in my case)? Will the UPS shut off too soon - and if so, where does it "rob" the time from (the on-battery delay? ... or the command file? ... or the O/S shutdown?)? Conversely, what is the effect of setting it "too large" (eg. 30 minutes) - what happens during the "extra" time (eg. 12 minutes, in my case)?

I think I understand the Low Battery Signal value, found in the same area - but I just want to confirm. I believe that, even if all other conditions are normal (i.e. mains power is stable, etc.), when the UPS projects a remaining runtime which is less that the specified value (eg. due to old batteries, or other "sagging" battery conditions), it will initiate a shutdown sequence immediately. Is that right? In which case, I can see where I might want to set this value to 20 minutes (or more), to provide a safe environment - so that I won't be "caught short" if a power outage were to suddenly occur.

But I'm really missing the point about that Runtime Remaining Threshold.

Thanks!

Brant