User Manual

Global objects and functions
Examples of global objects
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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.
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.
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).
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.
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:
● 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.
Periodic
synchronization
Add and delete devices
Link the system time of
a site with operator
units
Daylight saving time
changeover
Global properties