•
Failure to receive a periodic time synch from the backup clock will result in a backup clock lost event/
alarm (if configured). The period before raising the alarm is the user setting Backup Time Sync Lost
Delay.
•
Failure to receive a periodic time synch from the master and backup clock will result in a time synch not
received event/alarm.
Master Clock Backup Clock Master Clock Lost
Alarm
Backup Clock Lost
Alarm
Time Synch Not
Received Alarm
None None No No No
Yes None Yes No Yes – from master
clock
Yes Yes – same source
as master clock
Yes No Yes – from master
clock
Yes Yes – different
source as master
clock
Yes Yes Yes – from backup
clock
•
At power-on the alarms Master Clock Lost, Backup Clock Lost, and Time Sync Not
Received will be raised until the first valid time synch is received when the setting indicates the device
is connected to a clock. Once the time synch is received these alarms will be cleared.
•
An alarm will be provided to indicate if the clock has reset time to default time due to capacitor/battery
backup discharge or failure.
•
The binary input can be used for synchronizing the time. This will be done upon receiving a 0→1 transi-
tion on the user selectable BI (Binary Input Clock Synch). When the transition is detected the software
clock will be synchronized to the nearest minute or hour as specified by the user parameter Clock
Sync. from BI.
–
Clock Synch from BI/Seconds
When a pulse is received on the configured binary input Clock Sync. The milliseconds will be reset
to 0 and the time is adjusted to the nearest second.
–
Clock Synch from BI/Minutes
When a pulse is received on the configured binary input Clock Sync. The millisecond and seconds
will be reset to 0 and the time is adjusted to the nearest minute.
Time Server in the Network
For time synchronization via Ethernet according to Simple Network Time Protocol (SNTP), a time server must
be present in the network. 1 or 2 time servers are supported. This time server must also be able to address the
different time requirements of the devices as defined in SNTP. Time servers can be reached through an IP
address.
The Simple Network Time Protocol is used to synchronize clocks via the Internet. With SNTP, client computers
can synchronize their clocks with a time server via the Internet. SNTP enables a time resolution of 1 ms. When
considering similar runtimes, SNTP can determine the average runtime of a synchronization telegram between
the client and the server in the Ethernet network. This transmission time can be taken into account in the
terminal device and improves synchronization of terminal devices.
SNTP is available for the integrated Ethernet interface.
Version SNTPv4 is supported.
A fault time indication is output when the clock server does not respond to inquiries from the device after the
configured monitoring time expires. A time fault will be set in the time stamp of all indications.
The time fault indication does not appear when the SNTP server itself has no connection to the time source.
However at device start up, as long as no connection has been established with the SNTP server or the time
synchronization message indicates a Stratum greater than 3, the bit ClockNotSynchronized will be set in
the time stamp.
The device supports 2 SNTP timer servers, the first, primary server remains the preferred server so that all
devices, if possible, operate with the same master clock.
Basic Structure of the Device Functionality
2.5 Real Time Clock
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 37
C53000-G7040-C014-1, Edition 11.2019
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