Siemens SICAM Q80 Operating Instruction page 43

position have been located. Upon the next start, the last position data are used, and the satellites are found found
more quickly.
With a direct line of sight to the sky, the receiver is typically synchronized within one minute.
11.3.1.4 NTP Network Time Protocol
The Network Time Protocol (NTP) is a standard for synchronizing clocks in computer systems and uses the
connectionless transport protocol UDP. It was specially developed to enable reliable timing via networks having
variable package runtimes.
Precision: NTPv4 can keep a local system's time via the public Internet at a precision of 10 milliseconds; in local
networks under ideal conditions, precision levels of 200 microseconds and even better are possible.
Duration of synchronization process: Synchronization on an NTP server is a lengthy process. At intervals of 64
seconds, SICAM Q80 7KG8080 exchanges a data package with the server. Initially, 4 x64s are needed to set the
clock, after which the clock is synchronized at 64s intervals. It can take up to 3 h to reach precision in the range of
20ms. In order for the synchronization to begin upon activation, the measurement device must be set to use NTP
by default.
SICAM Q80 7KG8080 supports up to two NTP servers. For setting NTP, the following parameters in the device
properties are needed:
selection of the time zone
observance of the daylight saving's time transitions
IP of the NTP server (1)
IP of the NTP server (2)
Maximum time deviation [ms] from the server
11.3.2 Separate synchronization of all devices
If connection between devices via a Sync line is not possible, then each device can be synchronized separately to an
external clock.
11.3.2.1 GPS-time
GPS time: Each device is synchronized to absolute GPS time and thus all devices are mutually synchronized.
The synchronization between devices synchronized with NTP (see
Separate synchronization of all devices.
To reduce the time needed for synchronization, the standard synchronization signal should
be defined with the device properties (see system manual section Operation modes and
settings\Network quality\Measurement\Start/Stop Network analysis\Setting the start/stop
time)
Example for synchronization with GPS for stand alone devices
Connections and Conditioning
) is within approx. 1ms in the best cases.
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Power Quality Recorder SICAM Q80 7KG8080, Operating instruction
E50417-B1074-C419-A2, Release 12.01.2015
E-43
NTP time via LAN under