Reference Priorities: Examples - Spectracom VelaSync 1232 User Manual

3.3 Managing References
How long will the User/User reference be valid?
Since the User/User reference does not qualify as a legitimate, traceable time, it
becomes invalid once VelaSync is reset, or power-cycles, or after the Holdover Time
expires (whichever occurs first). It then needs to be set manually and submitted again
(Edit System Time
The only workaround for this is
This will allow VelaSync to apply the
manual intervention.
How to setup the User/User Reference
See "Manually Setting the Time" on
Using the "User" Reference with Other References
If the User/User
as GNSS or IRIG), the
Otherwise, the large time correction that needs to be bridged when switching from a
lost reference to a valid reference, or from a valid reference to a higher-priority ref-
erence that has become available again, will cause NTP to exit synchronization. If the dif-
ference is under 1 second, NTP will remain in sync and will "slew" (over a period of time)
to the new reference time.
3.3.1.4 Reference Priorities: EXAMPLES
Example 1 – GNSS as primary reference, IRIG as backup:
In this use case, the objective is to use:
GNSS as the primary Time, and 1PPS reference
IRIG as the backup Time, and 1PPS reference.
Step-by-step procedure:
1. Move the reference which has "GPS 0" in the
1PPS
checkbox.
2. Move the reference which has "GPS 0" in the
1PPS
checkbox.
118
> Manual Time Set).
"Using Battery Backed Time on Startup" on
page 99.
reference is used in conjunction with other, external references (such
System Time should be set as accurately as possible:
column to the top of the table, with a
column to the top of the table, with a
User/User reference after a power-cycle without
Time column and "GPS 0" in the
Priority value of 1. Click the
Time column and "GPS 0" in the
Priority value of 1. Click the
CHAPTER 3 • VelaSync User's Manual Rev. 3
page 101.
Enabled
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