Specifications

G4500 BLACKBOX PORTABLE OPERATIONAL MANUAL
August 2010
Elspec | Time Synchronization
99
RTC is powered by a battery to maintain clock progress even when the
BLACKBOX device power is off.
 The Time Sync module provides the BLACKBOX system with a
global time format called GMT or UTC. Using a global time approach
enables the BLACKBOX to synchronize measurements with other
BLACKBOXs located somewhere else around the globe. While the time
being recorded with PQZIP files is always GMT, the time shown on the
WEB interface is the local time (refer to Unit Time at the bottom of the
WEB page). The Local time is internally computed by the BLACKBOX
from the UTC obtained from the Time SYNC module plus the Time
Zone (which is the number of hours offset per specific country/area).
The Time Zone is configurable (under Service tab, Unit setup page, Time
Setup section).
The Time SYNC module also provides the source and the expected quality
of time in Synchronization Status. (Refer to Monitoring Section on
page 47)
In this example the Main refers to primary NTP Server, while the Good re-
fers to a good quality of time synchronization (meaning that the
learned/estimated time is very close to the true GMT obtained from the ex-
ternal time source).
Displayed Time Sources:
 Main: Primary NTP Server source is currently the active time source.
 Alternate: Alternative NTP Server is currently the active time source.
 GPS: GPS is currently the active time source.
 Self: RTC is currently the active time source.
Displayed Time Synchronization Quality/Accuracy:
 Perfect: Perfect time quality, expected less than 10 [microseconds] de-
viation from GMT