Alstom DS Agile H38 Series, Инструкция по установке и эксплуатации

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Global Documentation H38x/EN GL/D11
DS Agile H38x Page 19/53
3.4 Time Synchronisation
This product supports real-time clock synchronisation using Precision Time Protocol (PTP in
accordance with IEEE1588) to provide IRIG-B time, and Network Time Protocol (NTP) for
the timestamp of logs or events.
A one pulse-per-second (PPS) signal is generated and is displayed on an LED labelled as
“Heartbeat” on the display.
3.4.1 Precision Time Protocol (PTP)
Time synchronisation from a master clock synchronised to the global positioning satellite
(GPS) system is accepted over the network according to IEEE 1588 and the time can be
converted to another time format (IRIG-B & NTP).
PTP synchronises all clocks within a network by adjusting distributed clocks to a
grandmaster clock. PTP enables distributed clocks to be synchronised and maintained to
sub-microsecond accuracy.
3.4.2 Network Time Protocol (NTP)
Network Time Protocol (NTP) is a networking protocol for clock synchronisation between
computer systems over packet-switched, variable-latency data networks.
The switch can be synchronized by the NTP protocol as an NTP client.
3.4.3 IRIG-B
A time synchronisation signal compliant with the Inter-Range Instrumentation Group time
code B (IRIG-B) is generated within the product. This synchronization is valid only when the
switch is synchronized by PTP (1588)
The signal is in accordance with the standard IRIG_B 126: sine wave carrier (amplitude
modulated) at 1 kHz (1ms resolution), Binary Coded Decimal (BCD) with Straight Binary
Seconds (SBS)). The IRIG-B time reference provided is the UTC time.
The signal is presented on a connector located between the LEDs. An SMB connector is
used which provides 2KVrms isolation and >100MOhms insulation resistance. Up to 10
devices can be connected for synchronisation.
3.5 User Interface
Light Emitting Diodes (LEDs) and alarm contacts are used to indicate the status of the
product and its ports. A TELNET port for configuration and interrogation completes the user
interface.
3.5.1 LED Indications
The LED indication assignments are shown in the figure below.