EndRun Meridian II, Руководство пользователя

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M e r i d i a n I I U s e r M a n u a l 96
C H A P T E R N I N E
97 M e r i d i a n I I U s e r M a n u a l
P T P / I E E E - 1 5 8 8
NOTE
If using a single Grandmaster, keep the default setting of 128 for Priority 1 and Priority 2. If using two
redundant Grandmasters, then you can configure the preferred clock by setting Priority 1 to 127 and Prior-
ity 2 to 128.
The PTP Delay Mechanism is user configured to either E2E or P2P. E2E uses the delay request-re-
sponse mechanism and P2P uses the peer delay mechanism.
The PTP Domain is user configured in a range from 0 to 255.
The PTP Time Mode is user configured to either UTC or PTP. When UTC Time mode is configured
the clock transmits the UTC epoch and sets the PTP Scale to ARB. When the Time mode is PTP the
clock transmits the PTP epoch (TAI) and sets the PTP Scale to PTP. See
About the PTP Second and
UTC Time at the end of this chapter for more information.
The PTP Multicast TTL is user configured in a range from 1 to 255. For a local area network the TTL
should be configured to 1.
PTP Clock Class one of SYNCHRONIZED, HOLDOVER, or UNLOCKED. The Clock Class is
SYNCHRONIZED when the GPS Subsystem TFOM level is less than or equal to 4 (see Appendix A
- TFOM
). The Clock Class is HOLDOVER when the GPS Subsystem TFOM level is greater than 4
and less than 9. The Clock Class is UNLOCKED when the GPS Subsystem TFOM level is 9.
The PTP Timescale either PTP or ARB. When Time Mode is configured to PTP the clock transmits
the Timescale as PTP. When the Time mode is UTC the clock transmits the Timescale as ARB.
The PTP Port State is one of MASTER, PASSIVE or LISTENING. The PTP Port State is selected as
MASTER by the best master clock algorithm, otherwise it is PASSIVE or LISTENING.
The PTP Clock Source is either GPS or OSC. The Clock Source is GPS if the Clock Class is Syn-
chronized, otherwise it is OSC based on the system oscillator.
The PTP UTC Offset is the offset between TAI and UTC in units of seconds.
The PTP UTC Offset Valid is either TRUE or FALSE. The UTC Offset Valid is TRUE if the current
UTC Offset is known to be correct, otherwise it is FALSE.
The PTP Clock Accuracy is transmitted when the time is accurate to within the the following:
25ns Clock is synchronized or in holdover, PTP clock < 25 nanoseconds
100ns Clock is synchronized or in holdover, PTP clock < 100 nanoseconds
250ns Clock is synchronized or in holdover, PTP clock < 250 nanoseconds
1us Clock is synchronized or in holdover, PTP clock < 1 microsecond
2.5us Clock is synchronized or in holdover, PTP clock < 2.5 microseconds
10us Clock is synchronized or in holdover, PTP clock < 10 microseconds
25us Clock is synchronized or in holdover, PTP clock < 25 microseconds
100us Clock is synchronized or in holdover, PTP clock < 100 microseconds