Be sure that valid time and 1PPS references are currently selected (go to
MANAGEMENT/OTHER/Time Management).
In order to operate properly as a Master Clock, NetClock must be synchronized to a non-PTP
reference. Confirm that the chosen reference transmits the following information (as reported
by the Time Properties on the PTP Status page, under the Advanced tab):
The proper TAI or UTC time (including the current year)
The current TAI to UTC offset (required even if the reference’s time is in TAI)
Pending leap second information at least a day in advance.
If the reference does not transmit this information, it must be provided by the user in order for
the Master Clock to function properly.
The built-in GNSS reference provides all information needed with no user intervention.
5.2.7.5 Configuration — PTP-Specific Steps
Confirm that:
The PTP Port Activity is enabled (check the Port Status on the PTP Status page under the
Advanced tab). If not, enable it from the Port Activity of the PTP Setup/Network page).
The clock is set to be a Master-Only clock (check the Clock Mode on the PTP Setup/C
lock page).
A valid IP address is currently being used (check the Ethernet Settings on the PTP
Setup/Network page).
When the PTP Module is set to be a Master Clock, the module will immediately attempt to
become the active Master Clock on the network (PTP Port State = Master). If it does, it will start
to transmit PTP packets (even if NetClock is not yet synchronized).
There are several reasons why the PTP Module may not become the active Master Clock, or
may not be broadcasting the correct time, even if it is set to be a Master Clock:
a.
If using any reference other than self for 1PPS, NetClock will not become an active
Master Clock until the Time Figure of Merit (TFOM) value of the system is less than 15.
After first going into sync after power-up, it may take a minute or two for the Time Figure
of Merit (TFOM) value to fall to an acceptable level. The current Time Figure of Merit
(TFOM) value is available in the Time Properties panel under the Advanced tab on the
Status page.
b.
PTP uses the TAI timescale to transfer time. Many timing references communicate time in
the UTC timescale. UTC is offset from TAI by a small amount which changes every time a
leap second occurs. The TAI to UTC Offset is part of the PTP Specification and must be
376 NetClock User Reference Guide
APPENDIX
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