Re: UPS Power Control Program

[PaulMmn <PaulMmn@xxxxxxxxxxxxx>]

Ah, yes...   how long will the battery last...

Well, one way is to perform an actual test:  End all subsystems to
restricted state, then turn off the switch to utility power, and wait for
the battery to go dead.

The other way is to determine the load you want to protect, then talk to
the UPS vendor and ask them to certify how long the battery will last.
Tricky part of determining the load is that you can't just look at the name
plate on the AS/400 to determine the load.  After you get done adding
additional DASD and cards and etc., the load is, uh, different.  An
electrician should be able to measure the current load, and calculate the
load.

An equally fun calculation is how long your UPS needs to keep the power
flowing after a power failure--  you need X seconds (2.xx something) of
battery life per Megabyte of main memory (worst case) to allow the AS/400
to close files, put things away, and do a quick power down.  That's in
addition to any time you need to allow that batch job that's almost done to
finish, to send messages to the operator, etc.

For a 1024 Meg memory RISC system, it works out to be about 48 minutes just
for the system to shut down in an orderly fashion!  Uh, IBM did say that's
worst case...   (:

As far as a program--  we wrote one years ago, but we've migrated to
ROBOT/UPS from Help Systems.

--Paul E Musselman
PaulMmn@ix.netcom.com



>Has anyone written a power control program they like?  I have never written
>one and am curious about what folks think the best way to handle one is.
>How is the best way to determine how much battery is really there?
>
>TIA
>
>Jim Oberholtzer
>joberholtzer@compures.com



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