On Thu, 23 Jun 2016 11:43:19 -0400 Lennart Sorensen via talk <talk@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
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