[time-nuts] 60hz west coast electric grid gone berserk

Hal Murray hmurray at megapathdsl.net
Fri Sep 9 13:17:12 EDT 2011


> What software do you use for the monitoring?

Things are pretty simple if you have a Linux box.  Here is the code I'm using:
  http://www.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz.py

Kernel support to capture PPS info into NTP was developed many years ago.  
The API gives you a time stamp and a count.  Although the intention was 1 Hz, 
it works fine at 60 Hz.  It's available on recent Linux kernels and has been 
available on most/all *BSD systems for a long long time.

Linux also makes that info available via /sys/class/pps/pps0/assert so you 
can get at it with scripts and don't need to write/compile c code.
  [murray at shuksan]$ cat /sys/class/pps/pps0/assert
  1315583280.999957314#763070
  [murray at shuksan]$ 

It wouldn't be hard to write something similar in c that would run on a BSD 
box.



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