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
>
Manual Time Set
).
The only workaround for this is
"Using Battery Backed Time on Startup" on page 101
.
This will allow VelaSync to apply the
User/User
reference after a power-cycle without
manual intervention.
How to setup the User/User Reference
See
"Manually Setting the Time" on page 99
.
Using the "User" Reference with Other References
If the
User/User
reference is used in conjunction with other, external references (such
as GNSS or IRIG), the
System Time
should be set as accurately as possible:
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
Time
column and “GPS 0” in the
1PPS
column to the top of the table, with a
Priority
value of 1. Click the
Enabled
checkbox.
2.
Move the reference which has “GPS 0” in the
Time
column and “GPS 0” in the
1PPS
column to the top of the table, with a
Priority
value of 1. Click the
Enabled
checkbox.
118
CHAPTER
3
•
VelaSync User's Manual Rev. 3
3.3 Managing References
Summary of Contents for VelaSync 1225
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Page 34: ...BLANK PAGE 1 9 Regulatory Compliance 22 CHAPTER 1 VelaSync User s Manual Rev 3...
Page 104: ...BLANK PAGE 2 11 Configuring PTP 92 CHAPTER 2 VelaSync User s Manual Rev 3...
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