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8030HEPTA/GPS GPS - NTP Time Server with 2x 10/100/1000 MBit LAN Interface - V04.00
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hopf
Elektronik GmbH
Nottebohmstr. 41
• D-58511 Lüdenscheid • Tel.: +49 (0)2351 9386-86 • Fax: +49 (0)2351 9386-93 • Internet: http://www.hopf.com • E-Mail: [email protected]
8.3.3.4.3 Crystal Operation
Crystal Operation / Switch to Specific Stratum
If the Sync Source (here Module 8024
GPS) runs in crystal operation (status “crystal“) the NTP
service of the Time Server 8030HEPTA/GPS usually behaves in the way that the receipt of
time information is stopped from the Sync Source and the stratum value reset to 16 (defined
as invalid in NTP).
NTP Clients do not accept time information from a NTP Time Server with
stratum 16 (invalid). Briefly, as long as the Time Server 8030HEPTA/GPS
indicates the stratum value 16, NTP Clients are not synchronized.
This behaviour of NTP during crystal operation of the Sync Source can be changed. Therefore
the function "
Switch to specific stratum
" should be enabled by setting the value to "
enabled
"
and the so-called downgrading stratum (= stratum value of the Time Server 8030HEPTA/GPS
during crystal operation of the Sync Source).
For the synchronization of NTP Clients during crystal operation of the Sync Source or for test-
ing the system without connected synchronization source, in the setting "
enabled
" any stratum
value between 1 and 15 can be set.
Crystal Operation / Stratum in Crystal Operation
The value defined here (range 1-15) designates the transmitted fall back NTP stratum level of
the module in "
Quartz
" synchronization status. Stratum 1 should be configured if downgrading
is not desired in status "Quartz".
The NTP service MUST also be restarted (see
Chapter 8.3.3.6 Restart
Using the option "
Switch to specific stratum
" the NTP Clients are synchro-
nized with time information indicated in the general menu of the WebGUI of
the Sync Source (here Module 8024GPS) during crystal operating. Whether
this time information (e.g. through drift) is imprecise or the time is manually
set (wrong) cannot be detected by the NTP Client!
In case the value 1 is used for
"Stratum in crystal operation"
, the NTP Cli-
ent cannot not verify whether the Time Server 8030HEPTA/GPS is syn-
chronised or runs in crystal operation. Should a differentiation be wished
between synchronized and crystal operation the downgrading stratum
needs to be set to a value between 2 and 15.
The value is only adjustable if the "
Switch to specific stratum
" function is enabled.
