[ANSS-netops] xlak date stamp wrong; notes on NCSN TrueTime fix

[Dietz, Lynn]

Will Kohler logged onto the School Peak TrueTime via its serial port
interface, and found that the year returned by the F68 command (Year
Entry for GPS Epoch Management) was 1996.  We set this year to 2013
and did a warm restart F79, and the reported time was corrected.  We
also power-cycled the TrueTime to verify that our fix would survive,
and it did. Now F68 reports the current year, and the output time is
correct. Adsend is running again, producing properly-timestamped data.

FYI, only the School Peak TrueTIme clock (1 of 7 in the network) went
to Jan 2, 1994 this past weekend. It's firmware rev is:

School Peak F18:  TRUETIME XL     ACE3 sys ver 030 GPS-XL V1.047   182-6064v008

The manual says that the firmware is supposed to keep the F68 year
up-to-date if the clock has GPS lock, so we're not sure why this one
was set at 1996.

I will visit our other TrueTime clocks, ensure that F68 shows 2013,
and note their firmware revs.

Lynn


On Sun, Aug 18, 2013 at 2:03 PM,  <mwithers at memphis.edu> wrote:
>
> We were manually able to reset the dates and it seemed to keep the correct
> date after a power cycle.  It was suggested that it might be a epoch
> rollover
> of a 10 bit week number.  They occur a little more than every 19 years.  The
> last one was in January 1999 so the next one shouldn't happen until 2019
> (more modern systems use 13 bits to store the week number).  Its possible
> depending on how the firmware was written to handle the first rollover, that
> subsequent rollovers would occurr on 19 year intervals with a static offset
> from 1999.  That would mean that our clocks would return to 1994 (and I
> think in fact that they did).  So perhaps it did rollover and the firmware
> had the ability to recognize and account for the next rollover once we
> manually intervened?
>
> Unfortunately, now we have a few remote nodes to visit.
>
> Mitch
>
> Center for Earthquake Research and Information (CERI)
> University of Memphis                Ph: 901-678-4940
> Memphis, TN 38152                   Fax: 901-678-4734
>
>
> On Sun, 18 Aug 2013, Oppenheimer, David wrote:
>
>> Yes. We had a true time clock at remote EW node exhibit the same behavior.
>> the hour minute were correct.  Wierd
>>
>>
>> On Sun, Aug 18, 2013 at 9:18 AM, <mwithers at memphis.edu> wrote:
>>
>>>
>>> Is anyone else who still uses analog data and gets time from an XLAK
>>> having
>>> problems?  All of our clocks appear to have reset to Jan 2, 2013 at UTC
>>> midnight last night.  This causes adsend to have the wrong date.  And if
>>> you have adsend set to sync the system time to it, your system date is
>>> wrong.
>>>
>>> Mitch
>>>
>>> Center for Earthquake Research and Information (CERI)
>>> University of Memphis                Ph: 901-678-4940
>>> Memphis, TN 38152                   Fax: 901-678-4734
>>>
>>>
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>>>
>>
>>
>>
>> --
>> David Oppenheimer                   office: 650.329.4792
>> U.S. Geological Survey              fax:    650.329.4732
>> 345 Middlefield Road - MS 977   email: oppen at usgs.gov
>> Menlo Park, CA 94025
>>
>