User Manual

Global o
bjects and functions
Time synchronization
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For life check and replication the primary server has a list [BckUpSrv] of all
known devices of a site. The primary server automatically adds newly
commissioned devices on the site to this list. Devices which are removed from
the site must be deleted manually in Xworks Plus (XWP) from the list in the
primary server.
The primary server performs a life check at regular intervals, to check that all
devices of its site are online. The interval between life checks is defined by the
synchronization request period [SynReqp]. During this period, the backup
servers are checked one after the other in a cyclical process. The interval
between two life checks can be calculated as follows:
t ≈ SynReqp / Number of
backup servers .
A short synchronization request period and a large number of backup servers
may involve a substantial communications load. Take this into account when
setting the synchronization request period in Xworks Plus (XWP).
If one or more devices are not online, the primary server generates an alarm
signal. The alarm is reset as soon as all devices are online again and have been
detected by the primary server. This ensures that problems, such as the failure
of a device, the termination of the HVAC-application processing of a device, or
faulty configuration (e.g., two primary servers in one site) are detected.
Each backup server monitors its own periodic life check by the primary server. If
a life check fails, or if no primary server has ever carried out any life checks on
this backup server, the backup server generates an alarm. The backup server
resets the alarm as soon as the primary server carries out a life check.
7.4 Time synchronization
Each automation station is assigned to a site.
The primary server is the time master. It represents the system time within a
given site. The primary server synchronizes the time in the other automation
stations at regular intervals.
If the primary server receives a time synchronization request which triggers a
time change, the primary server synchronizes the time in the other automation
stations.
The primary server transmits the time in UTC format (Coordinated Universal
Time) to the other automation stations (backup servers) and in UTC format or
local time format to the third-party BACnet devices.
Desigo PX
Desigo PX
Desigo PX
PXM30/40/50
Desigo CC
10664Z19en_07
Primary Server Backup Server Backup Server
Add and delete devices
Check if all devices are
online
Monitor if the life check
checks the backup
server