EMR-5000
IM02602012E
Accuracy
The accuracy of the SNTP server used and the accuracy of its reference clock influences the accuracy of the protection
relay's clock.
With each transmitted time information, the SNTP server sends information about its accuracy:
Stratum: The stratum gives information on how close the SNTP server within the cluster is to other NTP servers that
are connected to an atomic clock.
Precision: This is the accuracy, the SNTP server provides the system time.
Also the performance (traffic and data package transmission time) of the connected network has an influence on the
accuracy of the time synchronization A locally installed SNTP server with an accuracy of
≤200 µsec is recommended.
If this cannot be provided, the connected server's accuracy can be checked in the [Operation/Status Display/Time
Sync.] menu
:
The server quality gives information about the accuracy of the used server. The quality should be GOOD or
SUFFICENT. A server with
BAD
quality should not be used because this could cause fluctuations of the time
synchronization
The network quality gives information about the network's load and data package transmission time. The quality
should be GOOD or
SUFFICENT
. A network with
BAD
quality should not be used because this could cause
fluctuations during time synchronization
Using two SNTP Servers
When configuring two SNTP servers, the device selects the server with the lower stratum value because this provides a
more precise time synchronization If the servers have the same stratum value, the device selects the server with the
better accuracy (precision). It does not matter which of the servers is configured as Server 1 or Server 2. When the
last used server fails, the device automatically switches to the other server. When the server recovers, the device
switches back to the previous one with the better quality.
SNTP Commissioning
Activate the SNTP time synchronization by means of the [Device Para/ Time/ TimeSync] menu:
Select »
SNTP« in the time synchronisation menu.
Set the IP address of the first server in the SNTP menu.
Set the IP address of the second server, if available.
Set all configured servers to “active”.
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