User Manual

Global objects and func
tions
Examples of global objects
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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.
The backup server then triggers time synchronization of its recipients configured in Xworks Plus (Desigo
room automation server, third-party server, third-party BACnet devices). This can be in either UTC or local
time format.
Periodic synchronization
The time synchronization interval is defined in the property TimeSynchronizationInterval [TiSynIvl] (default
value: 150 minutes). The property can be configured in Xworks Plus (XWP) and adapted to the specific
situation via a switchable [AlgnIvl] offset [IvlOfs]. How these three properties function is defined in the
BACnet standard and implemented accordingly.
Add and delete devices
For time synchronization, the primary server has a list [TiSynRcp] containing the recipients configured in
Xworks Plus (XWP) and all known backup servers of its site.
The primary server automatically adds newly commissioned backup servers on the site to the list
[TiSynRcp].
Backup servers which are removed from the site must be removed manually from the primary server list in
Xworks Plus (XWP).
Link the system time of a site with operator units
The network-capable operator units do not belong to a site. The primary server does not update the time in
the operator units. The client can read and update the time, if required.
Daylight saving time changeover
The daylight saving time changeover does NOT take place in the primary server. Each automation station
makes this switch independently.
The date of the daylight saving changeover is set as a parameter in the primary server. The primary server
replicates the date on the backup server. The official (Central European) changeover date is set as default.
The local time in an automation station is a calculated variable. The calculation is based on the internal
time in UTC format, the property UTC offset [UtcOfs] and the date of the summer and winter time
changeover.
See Desigo CC User Guide (A6V10415471).
7.5 Examples of global objects
BACnet device object
Certain properties of the BACnet device object are defined as global, because from the perspective of the
system, they are required to have the same value throughout the site. These properties are set in Xworks
Plus (XWP). Examples:
Global properties
● Date and time for the summer and winter time changeover.
Daylight savings time start date [DsavSdt] (Default: last Sunday in March)
Daylight savings time start time [DsavSti] (Default: 02:00AM)
Daylight savings time end date DsavEdt] (Default: Last Sunday in October)
Daylight savings time end time [DsavEti] (Default: 03:00AM)
● UTC_Offset [UtcOfs]
Difference between UTC and local Winter time in minutes. Default value: – 60 mins (Central Europe). In
Summer, the effective difference [UtcOfs] is –60 mins (Central Europe: –120min).
● Synch.Request Period [SynReqp]
Period between life checks by primary server The load on the communications system generated by the
life check can be controlled with this parameter by adapting it to the site size. Default value: 1800 s.
● Name resolution interval [NamRI]
Periodic repetition for the resolution of references across devices. Default value: 900 s.
● COV resubscription interval [CovRI]
Time within which the automation station resubscribes to a subscribed value. Default value: 1800 s.
Local properties
Local properties which refer to the functionality of the life check / replication: