Specifications

APPENDIX D. GPS SYNCHRONIZATION HOW-TO 41
9. Configure the file hs nodes.conf at each of the sites. In this file you list ONLY the
computers from that site - do not list computers from other sites. For example:
pcatb56.cern.ch:40000
10. Start the hs master program on the master computer at each of the sites.
11. Choose the option ”Synchronize with PPS thread”
12. Enter the same time on all the master computers, but take into account the local
time. The program will report the time from the local GPS - you have to give the
reference time with respect to that time.
13. After this the master computers will wait for the reference time and when it comes,
they will reset the local clock cards. See the windows with the clock dumps to check
if they reset. Now the cards should be globally synchronized.
14. To check the synchronization:
• Put the clock cards in mode 16 (read last bad clock value):
clock_test 1 1 6
This command tells the clock card to output not the value of the counter, but
the value of the counter before the PPS correction is made.
• Check the numbers that appear in the clock dumps – they should be similar.
• Put the clock cards back into the normal mode (read time):
clock_test 1 3