L-VIS User Manual
186
LOYTEC
Version 6.2
LOYTEC electronics GmbH
Alarmed data points also possess other property relations. The ‘enableAlarm’ property
relation can be used to disable or enable alarm conditions when linked to a data point. The
property relations ‘highLimit’, ‘lowLimit’, ‘deadband’ can be used to modify analog alarm
conditions. The property relations ‘inAlarm’ and ‘ackPend’ are TRUE if a data point is in
an alarm state or needs acknowledgement, respectively.
When a data point is alarmed by a generic alarm server, which reports to a technology that
requires a dedicated technology data point (e.g., an alarm for a user register is reported to
BACnet), the required data point is automatically created and linked via the ‘nativeAlarm’
property relation.
Alarm server objects possess property relations that provide a counter value of active
unacknowledged, active acknowledged, and inactive unacknowledged alarms. These
property relations may be linked to other data points that can be used to process this
information.
Other devices can access the alarm information through a technology alarm server or the
Web service. These devices are
alarm clients
. They register with the alarm server and get
notified about changes to the alarm summary. Alarm clients can be used to display the
current alarm summary and to acknowledge alarm transitions. Depending on the underlying
technology, some restrictions may apply to the available alarm information and
acknowledgement behavior. Refer to the technology sections for more information.
10.3.2 Scheduling
Schedulers are objects that schedule values of data points on a timely basis. A scheduler
object is configured by which data points it shall schedule. This configuration is done by
the system engineer once, when the system is designed. The configuration of the times and
values that shall be scheduled is not part of that initial configuration and may be changed
later. This distinction has to be kept in mind.
A scheduler object sets its data points to predefined values at specified times. The function
of the scheduler is state-based. This means, that after a given time, the scheduler maintains
this state. It can re-transmit the scheduled values as appropriate (e.g., when rebooting). The
predefined values are called
value presets
. A value preset contains one or more values
under a single label (e.g., “occupied” schedules the values { 20.0, TRUE, 400 } ).
Which value preset is scheduled at what time is defined by a
scheduled event
. The event
defines the starting time, value preset and end time in a 24-hour period. Events can be one-
time events or recurring events. A schedule typically consists of a number of recurring and
one-time events, for instance one event for the weekdays Monday through Sunday. See
Figure 6 for an example of a schedule in a given calendar week.
Figure 6: Example of a recurring event in a schedule.
How scheduled events are recurring can be defined by choosing the appropriate event type:
One-time
: This event occurs exactly on one defined date.
