semaphore TBOX LT2-530 Series, Руководство пользователя, Страница: 94 / 197

Version : 1.09 94
Supplementary information
1. The time between phases 1 and 4 can be determined in RTU properties --> Advanced Alarms
properties
2. System Analog Variable: #40 [AlaPop3] indicates the quantity of alarms needing to be
acknowledged by POP3 connection and #43 [Pop3State] indicates the state of connection.
3. If escalation is required, Group of recipients can be associated to the alarm condition
4. Like other alarms, failure in sending SMTP alarms can be checked using System Digital Variable:
#06 [AlaErr] and System Analog Variable: #10 [AlaRec]
5. Error in POP3 connection can be detected also using System Digital Variable: #48 [POP3Err]
10.6. NTP Server
NTP stands for Network Time Protocol, an Internet standard protocol (built on top of TCP/IP) that assures
accurate synchronization of the clock of
TB
OX
LT2
.
The NTP Server represents a server dedicated to time synchronization.
The time synchronization is generated through an alarm recipient “NTP”.
TB
OX
LT2
connects to Internet
(through a connection: ISP, Ethernet or GPRS/3G) and then connects to the NTP server.
Example with a connection to Windows server through Ethernet
Examples of Servers:
time.windows.com
europe.pool.ntp.org
You will find valuable information, like lists of Servers with open access at:
www.ntp.org

public time server list
The organization pool.ntp.org proposes servers using DNS round robin, which make a random selection
from a pool of open access time servers. This is good enough when working with
TB
OX
LT2
.
Round Robin DNS technique is used when the number of access to a server is unpredictable, to balance
the use of IP addresses (load balancing technique).
10.6.1. Time accuracy
When setting time,
TB
OX
LT2
takes into account the propagation delay. This is particularly important when
connecting to the server via modem.
The precision is of 1 second.