[ntp:questions] Converting from Y-m-d h:m:s

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Sat May 15 20:35:20 UTC 2010


Marc Leclerc wrote:
> Hi,
>
> I am looking to stay on true time, the real issue here in those
> installation is not realy having the perfect time but that all the
> device in the field have the same time. There are new ways to acheive
> this such as IEEE 1588 but since no one is ready for this using GPS
> device is our closest friend. But it's funny you asked, soon we will
> tackel simple synchronous switching of breaker and then we'll have to
> keep up with the AC cycles

This is actually somewhat easier:

You only need 8 or 10 ms accuracy to do this, in order to determine the 
start of each 50 or 60 Hz cycle, then you phaselock your switch to the 
AC cycles.

Terje
>
> On 2010-05-15 05:04, Uwe Klein wrote:
>> Marc Leclerc wrote:
>>> Thanks for your answer, the system I am working on is an ARM Linux
>>> based embedded board. the device is intented for electric utilities
>>> and we must meet good time precision, this device requires 1ms
>>> precision but our next one will require micro second precision
>>> therefore I am going for the bigger goal right away.
>>
>> 'Question on the side:
>>
>> Are you really aiming for "True(TM)" time or
>> sitting syncronous on the AC cycles (50Hz/60Hz) ?
>>
>> uwe
>>
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>>


-- 
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"




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