[time-nuts] Line Voltage [Was: Anyone (ideally in the UK) ...]

Hal Murray hmurray at megapathdsl.net
Sun Jan 1 06:09:13 EST 2017


The nice thing about the APC units is that they are close to free if you are 
already going to purchase a UPS.

I agree that something like the Dranetz 658 would be better, but a quick peek 
at eBay shows prices far beyond what I'm willing to pay.

> What's the sample rate on your APC UPS?

I don't know what the internal sampling rate is.  The API is
  tell me the current voltage
  tell me the lowest voltage since the last time I asked
  tell me the highest voltage since the last time I asked

I think I decided it's an 8 bit ADC so the resolution is far from wonderful.  
(The step size on a couple of handy readings in 0.7 volts.  8 bits gives a 
full scale of 180 volts.))

I have a hack that reads as fast as it can.  If nothing interesting has 
happened, it adds a line to the log file every 5 minutes.  If the min or max 
voltage has change enough, it logs a line now.  That gives me reasonably 
accurate timing on short glitches without cluttering up the log file with 
noise.

-- 
These are my opinions.  I hate spam.





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