GE B30 UR Series Instruction Manual page 173

5 SETTINGS
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 B30 supports the Simple Network Time Protocol specified in RFC-2030. With SNTP, the B30 can obtain clock time
over an Ethernet network. The B30 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. UR series relays support unicast, broadcast, multicast,
and anycast SNTP functionality.
The setting enables or disabled the SNTP feature on the B30.
SNTP FUNCTION
To use SNTP in unicast mode,
set and is "Enabled," the B30 attempts to obtain time values from the SNTP/NTP server. Since many time
SNTP FUNCTION
values are obtained and averaged, it generally takes three to four minutes until the B30 clock is closely synchronized with
the SNTP/NTP server. It takes up to two minutes for the B30 to signal an SNTP self-test error if the server is offline.
To use SNTP in broadcast mode, set the
B30 then listens to SNTP messages sent to the "all ones" broadcast address for the subnet. The B30 waits up to 18 min-
utes (>1024 seconds) without receiving an SNTP broadcast message before signaling an SNTP self-test error.
The
SNTP UDP PORT NUMBER
When the
SNTP UDP PORT NUMBER
NOTE
GE Multilin
 
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
SNTP SERVER IP ADDR
SNTP SERVER IP ADDR
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 B30 is restarted.
B30 Bus Differential System
SNTP PROTOCOL
Range: Enabled, Disabled
Range: Standard IP address format
Range: 0 to 65535 in steps of 1
setting to "0.0.0.0" and
SNTP FUNCTION
5.2 PRODUCT SETUP
5
to "Enabled." The
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