Re: [ntp:questions] Change reference clock soon after DCF-signal islost
Rob nom...@example.com writes: Matuschka, Sebastian sebastian.matusc...@gcd-solutions.de wrote: The reason i want to switch very soon to another source when DCF77 signal is lost, is that I have to tell a FPGA when it should use the DCF77 signal and when to use an alternative source. The FPGA doesn't decodes the time but it uses the DCF77 signal to increment its internal RTC. The MCU on which the ntpd runs has to decide whether the FPGA should use the DCF77 or a once per second pulse from the MCU. I think this isn't a good design. In my experience, DCF-77 reception is simply not stable enough to directly use the pulses from the receiver as clock ticks. When there are thunderstorms, local interference, and sometimes propagation problems, there can be spurious extra pulses that you do not want to count. Or pulses can be missing. The PPS filter should be able to deal with that (plus indicating the problems). Also when decoding the DCF-77 pseudo-noise, you may lock quite closely to the signal. Don't expect a 5 Euro receiver to lock on pseudo-noise-however. Also by nature, DCF-77 will provide 59 pulses per minute, not 60. So you should slave a clock that, in turn, created the pulses. A good way of using DCF-77 is to collect the 59 pulses that make up a minute, average the offset between the pulse start and the local clock tick, decode the time from the pulse lengths, and then at the end of the minute decide if all this information is valid and should control the clock (adjusting the clock offset/frequency), or should be discarded as a whole. This is also what the DCF-77 drivers in ntpd do. Yes. Regards, Ulrich ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] Q: PPS clock's variables: Some look strange
Hi, I'm wondering if there's something wrong with the clock variables of a PPS clock. Looking aat those, I get: ntpq cl assID=0 status= clk_okay, last_clk_okay, device=PPS Clock Discipline, timecode=, poll=2455049, noreply=0, badformat=0, baddata=0, fudgetime1=0.000, stratum=16, refid=80.80.83.0, flags=0 (ntpd 4.2...@1.1438-o, used in a Meinberg LANTIME server) When reading the peer variables, I get: assID=0 status=21f4 leap_none, sync_atomic/PPS, 15 events, event_peer/strat_chg, version=ntpd 4.2...@1.1438-o Tue Oct 7 10:44:09 UTC 2008 (1), processor=i586, system=Linux/2.6.15.1, leap=00, stratum=1, precision=-19, rootdelay=0.000, rootdispersion=0.386, peer=54170, refid=PPS, reftime=cff11bac.e68208bf Wed, Jul 21 2010 9:09:32.900, poll=4, clock=cff11bb6.b1f500fe Wed, Jul 21 2010 9:09:42.695, state=4, offset=0.000, frequency=75.869, jitter=0.002, noise=0.002, stability=0.002, tai=0, LANTIME=lantime/PZF511/M3x/V5.28g/SN, access_policy=open access; please notify x...@.de for permanent associations, admin_contact=x...@.de, info_url=http://..de/.shtml; (some values obfuscated) Specifically I don't like: 1) stratum=16, while in the peer it displays: stratum=1 2) timecode= (without a value, not even double double-quotes (to ease parsing)) My suggestions: The PPS should inherit the stratum of the providing clock. As PPS has no read timecode, we could display 1 when the clock uses the assert edge, or 0 when the pulse uses the clear edge. Otherwise I'd remove the timecode variable from the list. (I was asking Meinberg, whether they use a modified version of ntpd. If it's not the case, I might file a bug report. But send your opinions first!) Regards, Ulrich ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
[ntp:questions] NTPGraffe V1 (FR !)
Sorry all in French language...sorry NTPGraffe rassemble 3 scripts en Perl, et une interface WEB pour visualiser différents graphiques (RRDTool) liées à des serveurs NTP, avec ou sans Autokey en plus. Doc : http://www.archil.fr/ntpgraffe/NTPGraffe-v1.xhtml Les sources : http://www.archil.fr/ntpgraffe/ntpgraffe-v1.tgz Cordialement ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPGraffe V1 (FR !)
ARCHI archi.laur...@gmail.com wrote in message news:0e10346c-cc33-4a10-8f36-8c88403dd...@k19g2000yqc.googlegroups.com... Sorry all in French language...sorry NTPGraffe rassemble 3 scripts en Perl, et une interface WEB pour visualiser différents graphiques (RRDTool) liées à des serveurs NTP, avec ou sans Autokey en plus. Doc : http://www.archil.fr/ntpgraffe/NTPGraffe-v1.xhtml Les sources : http://www.archil.fr/ntpgraffe/ntpgraffe-v1.tgz Cordialement Thanks for your posting, Archi. It's good to see someone providing a graphic tool for NTP, and the plots look useful. I managed just with MRTG alone, but I then wrote some programs which analyse working NTP in different ways, including having access to the loopstats files. http://www.satsignal.eu/mrtg/performance_ntp.php http://www.satsignal.eu/software/net.htm#NTPmonitor Merci, David ___ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
Re: [ntp:questions] NTPGraffe V1 (FR !)
Thanks a lot,
I known your workaround for NTP, and same in the mailing list NTP, and your
are in my documentation too.
Utils links : -- Divers programmes de « monitoring » dans tous les genres :
www.satsignal.eu (http://www.satsignal.eu/software/net.htm#NTPmonitor).
Best regards
2010/7/21 David J Taylor david-tay...@blueyonder.co.uk.invalid
ARCHI archi.laur...@gmail.com wrote in message
news:0e10346c-cc33-4a10-8f36-8c88403dd...@k19g2000yqc.googlegroups.com...
Sorry all in French language...sorry
NTPGraffe rassemble 3 scripts en Perl, et une interface WEB pour
visualiser différents graphiques (RRDTool) liées à des serveurs NTP,
avec ou sans Autokey en plus.
Doc : http://www.archil.fr/ntpgraffe/NTPGraffe-v1.xhtml
Les sources : http://www.archil.fr/ntpgraffe/ntpgraffe-v1.tgz
Cordialement
Thanks for your posting, Archi. It's good to see someone providing a
graphic tool for NTP, and the plots look useful. I managed just with MRTG
alone, but I then wrote some programs which analyse working NTP in different
ways, including having access to the loopstats files.
http://www.satsignal.eu/mrtg/performance_ntp.php
http://www.satsignal.eu/software/net.htm#NTPmonitor
Merci,
David
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Laurent Archambault
Under Linux
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