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The DSMs each have a GPS with a pulse-per-second signal. Using NTP reference clock software, each DSM is then a stratum 1 time server. NTP NTP on the DSM adjusts the CPU system clock based on the GPS reference clock, and generally reports that their system clocks have the GPS reference clock has less than a 50 micro-second offset from the times of the GPS PPS signalsystem clock.
To query the system clock on a tower DSM from flux, use the ntpq -p command, for example 50m:
ntpq -p 50m
remote refid st t when poll reach delay offset jitter
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LOCAL(0) .LOCL. 10 l 20d 64 0 0.000 0.000 0.000
oGPS_NMEA(0) .GPS. 0 l 5 16 377 0.000 -0.001 0.031
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flux is configured to use all 6 DSMs as network time servers. flux runs , using chrony, a NTP client. To display the current chrony status, use chronyc sources:
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The above shows that the clock on flux agrees to within a maximum 52 microseconds with each DSM, as indicated by the "Last sample" value in brackets, which is the estimated offset of the DSM time from the time on flux. The second character should be '*' (chrony on flux is sync'd to this server) or '+' (good server). Sometimes I've seen '-' (lately on 100m for some reason) indicating chrony does not have a high opinion of its time information, relative to the others.
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