[GTALUG] mysterious restarts

[ac]

On Thu, 23 Jun 2016 11:43:19 -0400
Lennart Sorensen via talk <talk at gtalug.org> wrote:
> 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.
> 
this is a very interesting thread, i frequently ponder personal grid
timing and other cycles using various oscillations, until the old 40Hz
streak lights up (sync) my life