[ntp:questions] PPS problem
David Lord
snews at lordynet.org
Wed Apr 2 20:25:18 UTC 2014
David Lord wrote:
.....
> I currently use a "Sure" gps, ntp-dev-4.2.7p433 on NetBSD-6
>
> I have a few significant differences in my ntp.conf
>
> #################
> tos orphan 10
A few more comments
tos orphan 10 # is to replace your three lines:
server 127.127.1.0 #lo server
fudge 127.127.1.0 stratum 7
restrict 127.127.1.0 noquery nomodify notrap
> tos mindist 0.4 # allows pps to kick in
> ^^^^^^^^^^^
> server 127.127.20.2 mode 18
You can use this as prefer peer:
server 127.127.20.0 prefer
> fudge 127.127.20.2 stratum 7 time2 0.407 flag1 0 refid GPSb
Required value for time2 will depend on your GPS model and
firmware version.
> server 127.127.22.2 minpoll 4 maxpoll 4
> server 127.127.22.2 flag2 0 flag3 1 refid PPSb
> server -4 <ntp0.mydomain>
> server -4 <ntp1.myisp> minpoll 8 maxpoll 10 iburst prefer
For what it's worth the last entry in my
/var/log/ntp-stat.20140402:
Wed Apr 2 17:36:00 GMT 2014
remote refid st t poll reach delay offset jitter
============================================================
-GPS_NMEA(2) .GPSb. 7 l 64 377 0.000 -1.940 8.828
oPPS(2) .PPSb. 0 l 16 377 0.000 0.000 0.004
+ns0.lordyne 81.187 3 u 64 377 1.363 -0.175 0.202
ns2.lordyne 192.16 2 u 64 377 0.498 -0.237 0.613
+ns1.lordyne 81.187 3 u 64 377 0.577 0.007 0.703
+ns3.lordyne 81.187 3 u 64 377 0.849 -0.486 0.690
*ntp1.xxxxxx 195.66 2 u 256 377 19.589 -0.943 0.403
associd=0 status=011d leap_none, sync_pps, 1 event, kern,
pll offset: -0.000317
pll frequency: -35.8115
maximum error: 0.406
estimated error: 3e-06
kernel status: pll ppsfreq ppstime ppssignal nano
pll time constant: 4
precision: 1e-06
frequency tolerance: 495.911
pps frequency: -35.8115
pps stability: 0.00480652
pps jitter: 0.002
calibration interval 256
calibration cycles: 6087
jitter exceeded: 7635
stability exceeded: 0
calibration errors: 20
ntp_adjtime() returns code 0 (OK)
modes 0x0 (),
offset -0.317 us, frequency -35.812 ppm, interval 256 s,
maximum error 406000 us, estimated error 3 us,
status 0x2107 (PLL,PPSFREQ,PPSTIME,PPSSIGNAL,NANO),
time constant 4, precision 0.001 us, tolerance 496 ppm,
pps frequency -35.812 ppm, stability 0.005 ppm,
jitter 1.500 us, intervals 6087, jitter exceeded 7635,
stability exceeded 0, errors 20.
David
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