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 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 com-
municate 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 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 setting the GPS
to UTC Offset).
c. The PTP protocol also provides for the transfer of Leap Second inform-
ation. If the active time reference does not provide Leap Second inform-
ation, 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.
SecureSync 2400 User Manual 513
APPENDIX
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