[ntp:questions] PPS ATOM clock set to falseticker

Udo Maltzahn udo.maltzahn at meinberg.de
Thu Aug 14 09:36:12 UTC 2003


Hi all,


I've just maked some tests with PPS support and the new NTP versions.
The NTP versions ntp-4.1.74 and the ntp-4.1.80 will set the ATOM clock
to Falseticker.

Test environments:

3 independent Linux systems with exactly the same hardware
connected each to Meinberg GPS167/OCXO with PPS 

All Linux systems running the same kernel 2.4.20
patched with the PPSkit-2.1.1


First system is running the ntp-4.1.2 without problems.
Also tested with other versions all ok (e.g. ntp-4.1.1).

 
The other systems running the ntp-4.1.74 and ntp-4.1.80.
When the NTP synchronize to the PPS it will be set to
Falseticker.




The configuration is as follows:


Linux-2.4.20-Nano: # cat /etc/ntp.conf

server  127.127.1.0                  # local clock
fudge   127.127.1.0 stratum 12       # local stratum
server  127.127.8.0 mode 135 prefer  # Meinberg GPS OCXO PPS activ
server  127.127.22.0                 # ATOM (PPS)
fudge   127.127.22.0 flag3 1         # enable PPS API
enable stats
statsdir /var/log/
statistics loopstats
driftfile /etc/ntp.drift
logconfig =all



Linux-2.4.20-Nano: # ntpq -p

     remote           refid      st t when poll reach   delay   offset 
jitter
==============================================================================
 LOCAL(0)        LOCAL(0)        12 l   34   64  377    0.000    0.000  
0.008
*GENERIC(0)      .GPS.            0 l   28   64  377    0.000   -2.630  
0.227
xPPS(0)          .PPS.            0 l   35   64   37    0.000    0.005  
0.008



Linux-2.4.20-Nano: # ntpq -c as

ind assID status  conf reach auth condition  last_event cnt
===========================================================
  1 41756  9014   yes   yes  none    reject   reachable  1
  2 41757  9624   yes   yes  none  sys.peer   reachable  2
  3 41758  9114   yes   yes  none falsetick   reachable  1



Linux-2.4.20-Nano: # ntpq -c "cv 41758"

status=0000 clk_okay, last_clk_okay,
device="PPS Clock Discipline", timecode=, poll=80, noreply=0,
badformat=0, baddata=0, fudgetime1=0.000, stratum=16, refid=80.80.83.0,
flags=4



Linux-2.4.20-Nano: # ntpq -c "rv 41758"

status=9114 reach, conf, sel_falsetick, 1 event, event_reach,
srcadr=PPS(0), srcport=123, dstadr=127.0.0.1, dstport=123, leap=00,
stratum=0, precision=-20, rootdelay=0.000, rootdispersion=0.000,
refid=PPS, reach=077, unreach=0, hmode=3, pmode=4, hpoll=6, ppoll=6,
flash=00 ok, keyid=0, ttl=0, offset=0.004, delay=0.000,
dispersion=188.379, jitter=0.008,
reftime=c2e5b728.00003232  Thu, Aug 14 2003  7:22:16.000,
org=c2e5b728.00003232  Thu, Aug 14 2003  7:22:16.000,
rec=c2e5b763.da790321  Thu, Aug 14 2003  7:23:15.853,
xmt=c2e5b76a.da81ba7f  Thu, Aug 14 2003  7:23:22.853,
filtdelay=     0.00    0.00    0.00    0.00    0.00    0.00    0.00   
0.00,
filtoffset=    0.00    0.00    0.00    0.01    0.01    0.00    0.00   
0.00,
filtdisp=      0.01    1.00    1.96    2.92    3.91    4.87 16000.0
16000.0



Linux-2.4.20-Nano: # cat /var/log/messages

...
Aug 14 07:13:34 Testsystem ntpd[470]: ntpd 4.1.80-rc1-r Thu Aug 14
09:10:39 CEST 2003 (1)
Aug 14 07:13:34 Testsystem ntpd[470]: signal_no_reset: signal 13 had
flags 4000000
Aug 14 07:13:34 Testsystem ntpd[470]: precision = 7.000 usec
Aug 14 07:13:34 Testsystem ntpd[470]: kernel time sync status 2040
Aug 14 07:13:34 Testsystem ntpd[470]: frequency initialized 12.784 PPM
from /etc/ntp.drift
Aug 14 07:13:34 Testsystem ntpd[470]: system event 'event_restart'
(0x01) status 'sync_alarm, sync_unspec, 1 event, event_unspec' (0xc010)
Aug 14 07:13:35 Testsystem ntpd[470]: peer LOCAL(0) event 'event_reach'
(0x84) status 'unreach, conf, 1 event, event_reach' (0x8014)
Aug 14 07:13:36 Testsystem ntpd[470]: PARSE receiver #0: packet format
"Meinberg GPS Extended"
Aug 14 07:13:36 Testsystem ntpd[470]: PARSE receiver #0: STATE CHANGE: 
-> UTC DISPLAY; TIME CODE; POSITION; (LEAP INDICATION; POSITION)
Aug 14 07:13:36 Testsystem ntpd[470]: PARSE receiver #0: SYNCHRONIZED
Aug 14 07:13:36 Testsystem ntpd[470]: clock GENERIC(0) event 'clk_okay'
(0x00)
Aug 14 07:13:36 Testsystem ntpd[470]: peer GENERIC(0) event
'event_peer_clock' (0x85) status 'unreach, conf, 1 event,
event_peer_clock' (0x8015)
Aug 14 07:13:36 Testsystem ntpd[470]: system event 'event_clock_excptn'
(0x07) status 'sync_alarm, sync_unspec, 2 events, event_restart'
(0xc021)
Aug 14 07:13:37 Testsystem ntpd[470]: peer GENERIC(0) event
'event_reach' (0x84) status 'unreach, conf, 2 events, event_reach'
(0x8024)
Aug 14 07:16:50 Testsystem ntpd[470]: system event
'event_peer/strat_chg' (0x04) status 'sync_alarm, sync_local_proto, 3
events, event_clock_excptn' (0xc537)
Aug 14 07:16:50 Testsystem ntpd[470]: kernel time sync disabled 2141
Aug 14 07:16:50 Testsystem ntpd[470]: system event 'event_sync_chg'
(0x03) status 'leap_none, sync_local_proto, 4 events,
event_peer/strat_chg' (0x544)
Aug 14 07:16:50 Testsystem ntpd[470]: system event
'event_peer/strat_chg' (0x04) status 'leap_none, sync_local_proto, 5
events, event_sync_chg' (0x553)
Aug 14 07:17:51 Testsystem ntpd[470]: peer PPS(0) event 'event_reach'
(0x84) status 'unreach, conf, 1 event, event_reach' (0x8014)
Aug 14 07:30:41 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:32:48 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:36:04 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:39:19 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:42:35 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:44:40 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:47:50 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:51:08 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:53:14 Testsystem ntpd[470]: pps sync disabled
Aug 14 07:58:36 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:00:55 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:05:01 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:07:09 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:09:30 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:13:34 Testsystem ntpd[470]: offset -0.002641 sec freq 12.835
ppm error 0.000083 poll 6
Aug 14 08:13:38 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:15:48 Testsystem ntpd[470]: pps sync disabled
Aug 14 08:18:06 Testsystem ntpd[470]: pps sync disabled
...






Can anybody comment on this?

Udo



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