[GTALUG] mysterious restarts

[Lennart Sorensen]

On Wed, Jun 22, 2016 at 07:39:34PM -0400, Michael Galea via talk wrote:
> No, the device is not a UPS. It is a PLC that measures voltages, currents,
> real and reactive power of a 3-phase service.  It provides me the results as
> IEEE754 32-bit floating point numbers. It's me that truncates to 2 digits.
> 
> You know I'm sorry I ever implied that the grid wasn't long term accurate at
> 60 Hz!  What I should have said was that in the short term the grid could be
> quite off 60 Hz but over the longer term it could average out.
> 
> If I really needed to know the answer to the question of "how much out", I
> would get ask the PLC to just count cycles and send me the count with a
> timestamp. That would tell.

Well wikipedia claims the grid can be off by up to 10 seconds in north
america on this side of the continent.  The west and texas allow a
lot less.  So it can certainly be a bit off for quite a while.

-- 
Len Sorensen