Furuno FMD-3200 Operator's Manual page 318

25. ALERT MANAGEMENT SYSTEM (option)
Device states
A sensor has two main states, N and A.
State N: No active alerts. The device should send a "no-alerts" message with an in-
terval of a maximum of 60 seconds. This message informs the AMS that the sensor
has no active alerts.
State A: The device has one or more active alerts, of which zero or more may have
been acknowledged and the rest (possibly zero) are unacknowledged. In this state,
the device shall send all active alerts at an interval not greater than 60 seconds. When
multiple alerts are active in the sensor, all active alerts are transmitted as a "list" of
alerts (alert-list message). In response to the "list", applicable sensors output the ALR
sentence, the content of which is defined in IEC 80/250/INF.
In addition to the periodic transmission mentioned, the sensor sends an Alert message
(ALR) to the AMS when an alert is generated in the sensor in the following instances:
• A new alert is generated in the sensor.
• An existing alert is acknowledged in the sensor, either by the sensor itself or by remote
acknowledgement by the AMS.
• An existing alert condition becomes non-active.
No-alerts message
The no-alerts message to informs the AMS that the sensor has no active alerts. It is
sent at an interval not greater than 60 seconds, and may be used to clear the AMS
alert list. This message is sent as an ALR message, without a time stamp and includes
a "V" flag in the both the alert condition and acknowledgement field. The no-alerts
message is as shown below.
$--ALR,,,V,V,*hh
The alert-list message
The alerts-list message periodically refreshes the alert list in order for personnel to
have up-to-the-minute list of active alerts. The alert / alert list message is sent with an
interval not greater than 60 seconds. The alert / alert list message consists of the
same message(s) sent when the corresponding event occurred, but all active alerts
shall be reported. An example of two alert-list messages are shown below.
$--ALR,123456,123,A,A,Battery power in use*hh<CR><LF>
$--ALR,130507,456,A,V,Self test failure*hh<CR><LF>
ACK sentence
The AMS sends the ACK sentence to all sensors to acknowledge alerts. The sentence
format is as shown below, where xxx is the Alert no. generated by each sensor.
$--ACK,xxx*hh<CR><LF>
This AMS supports only the single alert acknowledgement as defined by IEC 80/520/
INF. In this case, it is necessary to send an alarm acknowledge message, the format
which is shown below, from the external from the AMS to the sensor. The message is
sent at an interval not greater than 60 seconds.
$--ACK,*hh<CR><LF>
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