[time-nuts] 60hz west coast electric grid gone berserk
Hal Murray
hmurray at megapathdsl.net
Fri Sep 9 17:17:12 UTC 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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