On 06/22/16 21:44, James Knott via talk wrote:
On 06/22/2016 07:39 PM, Michael Galea via talk wrote:
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.
And how accurate is the PLC? Typical CPU clock crystals aren't that
accurate.
There are a few answers here.
If you just run the device stand alone the data sheet
(https://cdn.selinc.com//assets/Literature/Product%20Literature/Data%20Sheets/751A_DS_20150206.pdf?v=20150812-085325)
promises "Unsynchronized Clock Drift Relay Powered: 2 minutes per year".
If you use IEEE1588, 1uS.
If you use NTP, well.. 1 mS? That's the figure I always plan on.
--
Michael Galea
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