Spectracom NetClock 9400 Series, Руководство пользователя

Страница: 187 / 467

column to the top of the table, with a Priority value of 1. Click the Enabled checkbox.
3.
For all other references, uncheck the Enabled checkbox, so that they are all disabled.
If the objective is to use a manually set time as a
backup
to other references (such as GNSS or
IRIG):
1.
Move the "User/User" reference to a place in the table that has a priority lower than the
references the "User/User" reference will be backing up. Make sure the
Enabled check
box is selected.
2.
With “User/User” enabled, if no other higher priority references are enabled or avail
able (or if the higher priority references have since been lost), you can now manually set
the
System time to the desired value ( MANAGEMENT > OTHER: Time Management >
System Time > Manual Time Set ). See "System Time" on page 148 for more inform
ation. NetClock will go into synchronization using this set time once you click the Submit
button, and the front panel sync light will turn green.
Note: You will need to repeat this procedure each time NetClock is power-cycled
(with no other references available), unless you enabled the feature Synchronize
to Battery Backed Time on Startup.
Example 5—Time at power-up ("Local System Time") to be considered "Valid".
GNSS input to serve as 1PPS reference
The objective of this use case is to allow NetClock to use itself as a valid reference. This is
referred to as “Local System” time.
In order for this to happen, NetClock requires an external Time, or 1PPS reference. In other
words, "Local System" cannot be both Time,
and
1PPS. This makes "Local System" a legitimate,
traceable reference.
Therefore the "Local System" does not have to be manually set ("validated") by the User after
NetClock was power cycled (as would be the case with a “User/User” reference).
Since “Local System” cannot be both Time , and 1PPS input together, in this example the GNSS
input will be set as the 1PPS reference (other use cases may require using different references,
e.g. IRIG.)
As there is no default entry for “Local System” and “GPS”, a new entry needs to be added to
the
Reference Priorities table in order to use this combination of references.
Step-by-step procedure:
1.
Add a reference to the Reference Priority by clicking the PLUS icon. Use the following set
tings, then click
Submit :
In the Priority Level text box, enter 1 . This will give this reference the highest pri
ority.
3.3 Managing Input References
CHAPTER
3
•
NetClock User Reference Guide Rev. 16
171