GE L90 Instruction Manual page 336

PRODUCT SETUP
The L90 supports the Simple Network Time Protocol specified in RFC-2030. With SNTP, the L90 can obtain clock time over
an Ethernet network. The L90 acts as an SNTP client to receive time values from an SNTP/NTP server, usually a dedicated
product using a GPS receiver. UR family relays support unicast, broadcast, multicast, and anycast SNTP functionality.
The
SNTP FUNCTION
To use SNTP in unicast mode, set
is "Enabled," the L90 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 L90 clock is closely synchronized with the SNTP/
NTP server. It takes up to two minutes for the L90 to signal an SNTP self-test error if the server is offline.
To use SNTP in broadcast mode, set the
then listens to SNTP messages sent to the "all ones" broadcast address for the subnet. The L90 waits up to 18 minutes
(>1024 seconds) without receiving an SNTP broadcast message before signaling an SNTP self-test error.
The
SNTP UDP PORT NUMBER
Do not set more than one protocol to the same TCP/UDP port number, as this results in unreliable operation of
those protocols.
5.3.7.4 Local time
SETTINGS  PRODUCT SETUP  REAL TIME CLOCK  LOCAL TIME
 LOCAL TIME

5
The L90 maintains two times: local time and Universal Coordinated Time (UTC). Local time can be provided by IRIG-B
signals. UTC time is provided by SNTP servers.
The real-time clock (RTC) and time stamps reported in historical records and communication protocols can be incorrect if
the Local Time settings are not configured properly.
See the IRIG-B section in the Installation chapter for guidance on these settings when using an IRIG-B source that sets the
IRIG-B control bits according to IEEE Std 1344-1995.
LOCAL TIME OFFSET FROM UTC
zones in the eastern hemisphere have positive values; time zones in the western hemisphere have negative values. A value
of zero causes the relay to use UTC for local time. This setting has two uses. When the system RTC is synchronized with a
communications protocol providing only local time or it is free-running, the offset setting is used to calculate UTC from the
5-112
setting enables or disables the SNTP feature on the L90.
SNTP SERVER IP ADDR
SNTP SERVER IP ADDR
is 123 for normal SNTP operation. The change takes effect when the L90 is restarted.
LOCAL TIME OFFSET

FROM UTC: 0.0 hr
DAYLIGHT SAVINGS

TIME: Disabled
DST START MONTH:

January
DST START DAY:

Sunday
DST START DAY

INSTANCE: First
DST START HOUR:

2:00
DST STOP MONTH:

January
DST STOP DAY:

Sunday
DST STOP DAY

INSTANCE: First
DST STOP HOUR:

2:00
— Used to specify the local time zone offset from UTC (Greenwich Mean Time) in hours. Time
to the SNTP/NTP server IP address. Once this address is set and
setting to "0.0.0.0" and
Range: –24.0 to 24.0 hr in steps of 0.5
Range: Disabled, Enabled
Range: January to December (all months)
Range: Sunday to Saturday (all days of the week)
Range: First, Second, Third, Fourth, Last
Range: 0:00 to 23:00 in steps of one hour
Range: January to December (all months)
Range: Sunday to Saturday (all days of the week)
Range: First, Second, Third, Fourth, Last
Range: 0:00 to 23:00 in steps of one hour
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
to "Enabled." The L90
SNTP FUNCTION
SNTP