User manual

Operating Principles of XBT Terminals
33003962 11/2011 107
Storage Principle in the Alarm List
If the alarms have equal priority, they are stored from the oldest to the most recent.
If the display unit is available (i.e., not occupied by a higher-priority display), the
oldest alarm is displayed. In an automation system, it is often the oldest alarm that
is the most interesting, as the more recent alarms are often a consequence of the
condition signaled by the first alarm (classic case of bursts of alarms).
If alarms with higher priority occur the following will happen:
z Alarms with higher priority are stored at the top of the list.
z If the display unit is available (i.e., not occupied by a higher-priority display), the
new alarm with highest priority will be displayed.
Buzzer for Alarms Notification
You can set alert sounds to inform you of alarms by activating the buzzer of the
XBT RT511 terminal.
Acknowledg-ment of Alarms
When designing alarm panels, it is possible to define whether the alarm panel
should be acknowledged systematically by the operator (obligatory
acknowledgment) or not.
To acknowledge the alarm panel on the display press ENTER. The alarm message
changes to a steady display.
Depending on the choice made, management of these 2 types of alarm is as follows:
Alarms which must be acknowledged
(obligatory)
Alarms which can be acknowledged but
do not have to be
An alarm, which must be acknowledged,
remains in the alarm list until it is
acknowledged by the operator, even if the
cause of the alarm has disappeared.
An alarm, which can be acknowledged but
does not have to be, disappears from the
alarm list as soon as the cause of the alarm
has disappeared, regardless of whether or
not it has been acknowledged by the
operator.
Advantage: Picks up transient conditions
(instability of a discrete sensor, for example).
Advantage: The display unit is not
monopolized by displaying alarms
considered to be of minor importance to the
application.