On Fri, 2007-03-09 at 11:19 -0600, Mike McCarty wrote: > Mikkel L. Ellertson wrote: > > Mogens Kjaer wrote: > > > >>Mike McCarty wrote: > >>.... > >> > >>>Can you give me any reason why one would want to have extended > >>>conversations with an UPS if the only real option is to shut > >>>down anyway? > >> > >>Modern UPSes do a lot of selftests, especially on the > >>battery, so it is important to get a notification when > >>the battery needs to be replaced. > >> > > > > I have found that "smart" UPSs can provide you with other handy > > information as well. I like being able to find the charge level of > > hte battery, how much power the system is drawing, and things of > > that nature. If the UPS also does AVR, it can be handy to know how > > often it has to supplement or reduce line voltage. And while the > > calibration is not as good as I would like, they can also be used to > > record line voltage that can provide clues to other voltage related > > problems you may experience. (It can save you from having to attach > > a recording volt meter.) > > Hmm. I don't want to use my computer as a voltmeter, nor as a line > condition monitor. The only action one seemingly can take is to > shut down when a power failure occurs. What are you going to do > with this information? Complain to your power company? They don't > guarantee any degree of quality of service. They only guarantee > not to charge you for electricity you don't use. > > Getting an indication that the battery needs replacement might be > useful, but I doubt it, since I doubt the accuracy of the measurement. > I'd rather just time how long it takes to run down once a year. That > would at least be accurate, if damaging to the health of the battery. > > None of the rest sounds useful to me in the slightest. ---- Computer software calculates the remaining battery time from a 'smart UPS' system so it remains on line based upon the amount of battery remaining and factoring the draw rate. Without this 'smart' system, you are probably only getting a signal that power has switched to battery and do your best guess as to how long you can go before you shut down the system, which is not the best way to run a railroad. Whether or not you find this knowledge useful, most people do. -- Craig White <craig@xxxxxxxxxxxxx>
