Specifications

Appendix E
Troubleshooting synchronization
problems
Problems with the cables
• If the clock is not counting - probably the 10MHz signal from the GPS is not
plugged into the clock card.
• If the GPS does not synchronize, check the antenna connection and that the
antenna sees enough open sky (NOTE: in this case the clock card will not count
because the 10MHz signal will not be available).
• If the c lock is counting, the GPS is ok and the clock card does not reset on
request - there might by a problem with 1 Hz PPS signal from the GPS or with
the Write Down signal from the master clock card.
The hs master program
• If the hs master can’t communicate with the slaves – check the xinetd con-
figuration and the hs nodes.conf . Make sure only valid local site nodes
are listed there and also that the local master is in that file. Check the file
/etc/xinetd.d/hs daemon and make sure you have the correct path to the
hs daemon executable.
• The synchronization is not done – check the cables, try to manually reset the
clock cards, check if the GPS card is synchronized.
The clock cards
• The clock cards do not reset – make sure the PPS sync thread is not active (
clock test 1 14 ) and that the card is in the read time mode ( clock test
1 3 ). Also make sure that the master clock card is really a master card (you
can try to see the signals with an oscilloscope).
• The clock counter is 0 – send the read time command to the card: clock test
1 3
• The clock counter has a constant value different from zero – this looks like the
10MHz signal is no longer available – check the cables and the GPS.
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