GE N60 Instruction Manual page 185

5 SETTINGS
PORT 1 ... 3 PATH DELAY ADDER
• The time delivered by PTP is advanced by the time value in this setting prior to the time being used to synchronize the
relay's real time clock. This is to compensate to the extent practical for time delivery delays not compensated for in the
network. In a fully compliant PP network, the peer delay and the processing delay mechanisms compensate for all the
delays between the grandmaster and the relay. In such networks, this setting should be zero.
• In networks containing one or more switches and/or clocks that do not implement both of these mechanisms, not all
delays are compensated, so the time of message arrival at the relay will be later than the time indicated in the mes-
sage. This setting can be used to approximately compensate for this delay. However, as the relay is not aware of net-
work switching that dynamically changes the amount of uncompensated delay, there is no setting that will always
completely correct for uncompensated delay. A setting can be chosen that will reduce worst-case error to half of the
range between minimum and maximum uncompensated delay, if these values are known.
PORT 1 ... 3 PATH DELAY ASYMMETRY
• This setting corresponds to "delayAsymmetry" in PTP, which is used by the peer delay mechanism to compensate for
any difference in the propagation delay between the two directions of a link. Except in unusual cases, the two fibers are
of essentially identical length and composition, so this setting should be set to zero.
• In unusual cases where the length of the link is different in different directions, this setting should be set to the number
of nanoseconds the Ethernet propagation delay to the relay is longer than the mean of path propagation delays to and
from the relay. For instance, if it is known say from the physical length of the fibers and the propagation speed in the
fibers that the delay from the relay to the Ethernet switch it is connected to is 9 000 ns and the that the delay from the
switch to the relay is 11 000 ns, then the mean delay is 10 000 ns, and the path delay asymmetry is 11000 - 10000 =
+1000 ns.
c) SNTP PROTOCOL

PATH: SETTINGS PRODUCT SETUP
 SNTP PROTOCOL

MESSAGE
MESSAGE
The N60 supports the Simple Network Time Protocol specified in RFC-2030. With SNTP, the N60 can obtain clock time
over an Ethernet network. The N60 acts as an SNTP client to receive time values from an SNTP/NTP server, usually a ded-
icated product using a GPS receiver to provide an accurate time. Unicast SNTP is supported. The UR-series relays do not
support the broadcast, multicast or anycast SNTP functionality.
The setting enables or disabled the SNTP feature on the N60.
SNTP FUNCTION
To use SNTP,
SNTP SERVER IP ADDR
is "Enabled", the N60 attempts to obtain time values from the SNTP/NTP server. Since many time values are
FUNCTION
obtained and averaged, it generally takes three to four minutes until the N60 clock is closely synchronized with the SNTP/
NTP server. It takes up to two minutes for the N60 to signal an SNTP self-test error if the server is offline.
The
SNTP UDP PORT NUMBER
When the
SNTP UDP PORT NUMBER
NOTE
GE Multilin N60 Network Stability and Synchrophasor Measurement System
 
REAL TIME CLOCK
SNTP FUNCTION:
Disabled
SNTP SERVER IP ADDR:
0.0.0.0
SNTP UDP PORT
NUMBER: 123
must be set to the SNTP/NTP server IP address. Once this address is set and
is 123 for normal SNTP operation. If SNTP is not required, close the port by setting it to 0.
is set to 0, the change takes effect when the N60 is restarted.
SNTP PROTOCOL
Range: Enabled, Disabled
Range: Standard IP address format
Range: 0 to 65535 in steps of 1
5.2 PRODUCT SETUP
5
SNTP
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