The built-in GNSS reference provides all information needed with no user intervention.
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/Clock 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 SecureSync 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, SecureSync will not become an act-
ive 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 Spe-
cification and must be provided to a Master Clock. If no active reference can provide
that information, the offset must be provided by the Host. The TAI to UTC Offset
can be set from the MANAGEMENT/OTHER/Time Management page (while set-
ting the GPS to UTC Offset).
c.
The PTP protocol also provides for the transfer of Leap Second information. If the
active time reference does not provide Leap Second information, it must be added
by the user through the MANAGEMENT/OTHER/Time Management page. If this
is not done, the PTP network will have the incorrect UTC time after a leap second
event.
d.
If there are multiple multicast Master Clocks on the network, the PTP Module uses
the Best Master Clock (BMC) algorithm specified in the PTP Specification to decide
474 SecureSync 2400 User Manual
APPENDIX
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