[ntp:questions] PPS problem on Fedora Core 6
bogdanrus2004 at yahoo.com
Fri Jul 27 19:12:48 UTC 2007
My name is Andrei Bogdan Rus and I am from Romania. I have a problem and I don't know how to solve it. Mabey you can help me.
I am using a Trimble Palisade NTP Synchronization Sit. The computer used, runs Linux Fedora Core 6. When I configured the sistem to work with the gps receiver, everything worked fine. Now I am trying to make another computer running the same Linux distribution to sincronize with the NTP server and also to sincronize with the PPS pulse from the sinchronization kit.
I took the kernel that Rodolfo Giometti offered at the address http://wiki.enneenne.com/index.php/LinuxPPS_support to support the PPS API. I also installed the tools ppstest and ppsctl I found at http://ftp.enneenne.com/pub/misc/linuxpps/test/, My output when I run this tool is:
found PPS source #0 "serial0" on "/dev/ttyS0"
ok, found 1 source(s), now start fetching data...
source 0 - assert 1185518306.699172958, sequence: 10 - clear 1185516328.674035118, sequence: 9
source 0 - assert 1185518306.699172958, sequence: 10 - clear 1185518306.980946546, sequence: 10
source 0 - assert 1185518307.980928373, sequence: 11 - clear 1185518307.980907068, sequence: 11
source 0 - assert 1185518308.980868238, sequence: 12 - clear 1185518307.980907068, sequence: 11
source 0 - assert 1185518309.980829111, sequence: 13 - clear 1185518307.980907068, sequence: 11
source 0 - assert 1185518310.980810941, sequence: 14 - clear 1185518310.980789361, sequence: 12
As I read, this should be the output if I receive the PPS signal corectly to the interface. So the PPS signal reaches to the serial interface and it is received corectly.
I use NTP-4.2.2p4 with the refclock_atom patch downloaded from http://ftp.enneenne.com/pub/misc/linuxpps/refclocks/atom/
The problem is that my NTPD is not sinchonising with the pps signal. The configuration file is:
# /etc/ntp.conf, configuration for ntpd
peer 18.104.22.168 prefer #this is the server sinchronized with GPS Palisade kit
peer 127.127.22.0 prefer # the pps signal is connected to the pin 1 (DCD) from my serial interface. I have only one serial interface
fudge 127.127.22.0 flag3 1
As I read in the Driver22 tutorial from http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver22.html i did in /dev, the link pps0
The output from the command "ntpq -pn" is:
remote refid st t when poll reach delay offset jitter
*22.214.171.124 .GPS. 1 u 41 64 377 0.234 24.256 9.756
127.127.22.0 .PPS. 0 l - 64 0 0.000 0.000 0.001
and from the command "ntpq -c as" is:
ind assID status conf reach auth condition last_event cnt
1 10546 9634 yes yes none sys.peer reachable 3
2 10547 8035 yes yes none reject clock expt 3
So, as you see, the sistem is not sinchonising with the PPS signal. I don't know what is the reason.
I think that NTPD receives the signal, because in the log is written that refclock: found PPS source.... These are the /var/log/ntpd contents:
27 Jul 16:25:13 ntpd: refclock: found PPS source #0 "/dev/ttyS0" on "serial0"
27 Jul 16:25:13 ntpd: refclock_atom: time_pps_kcbind failed: Operation not supported
27 Jul 16:29:31 ntpd: synchronized to 126.96.36.199, stratum 1
27 Jul 16:29:34 ntpd: time reset +2.385646 s
27 Jul 16:29:34 ntpd: kernel time sync enabled 0001
27 Jul 16:32:55 ntpd: synchronized to 188.8.131.52, stratum 1
I found that other people had the log almost the same, but after sinchronising with the peer, there is another log message "synchonized to PPS(0), stratum 0", but I never get this message and is never synchronising.
I want to mention that the GPS receiver, receives signal from the satellites.
Thank you for your time, Have a god day
| ing. Andrei Bogdan RUS |
| Tel. +40-744-267970 |
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