Spectracom VelaSync 1225, User Manual

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Use cases for the "User/User" reference
The User/User reference is provided for the following use cases:
a.
No external references are available (yet), but you need a reference for testing or
setup purposes. This may be the case e.g., while waiting for a GNSS antenna to be
installed.
b. No external references are required e.g., if VelaSync is used solely to synchronize
computers on a network, with no need for traceable UTC-based timing.
c.
To utilize a backup reference as soon as possible after a power cycle or reboot of
VelaSync, while waiting for the primary reference (e.g., GNSS) to become valid.
To this end, in the
Edit System Time window, the checkbox Synchronize to Bat-
tery Backed Time on Startup must be checked, AND the User/User reference
is assigned a reference priority number other than "1". Note that a Time jump
and/or 1PPS jump are likely to happen once the primary reference becomes valid.
Combining a User Time reference with a non-User 1PPS reference or vice versa is not a
typical use case. Use the Local System reference instead, see "The "Local System"
Reference" on page 115 .
Built-in safety barrier
In order to "validate" (= green status lights) the User/User reference, the hand-set
time must be manually submitted every time after VelaSync reboots or resets, or after
the Holdover period has expired: In the
Edit System Time window, the checkbox
Manual Time Set must be checked. The System Time displayed in the field below will
become valid the moment the Submit button is clicked.
See also below, " How long will the User/User reference be valid? ": The notion of limiting
the validity of the User/User reference also serves as a safety feature.
3.3 Managing References
CHAPTER
3
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