Argus Radar - SERIAL INTERFACE SPECIFICATIONS
988-10187-004 2.34
NOTE 4
The alert instance identifies the current instance of an alert to distinguish
alerts of the same type (Alert identifier) and from the same source (e.g.
dangerous target). Alert instance is maximum 6-digit integer from 1 to
999999. The number of alert instance can be freely defined by the
manufacturer as long as it is unique for one type of alert (alert identifier). It is
not permitted to modify the alert instance within a life cycle of a distributed
alert (from ‘active-unacknowledged’ state until ‘normal’ state is reached). It
can also be a null field, when there is only one alert of that type.
NOTE 5
This should not be null field acknowledge: A request / repeat information: Q
responsibility transfer: O, silence: S
NOTE 6
This field should be “C” and should not be null field. This field indicates a
command. A sentence without “C” is not a command.
ALC – Cyclic alert list
The purpose of this sentence is to satisfy the needs for a safe and consistent data
distribution with a minimum of data traffic. Each change on an alert’s data leads to an
incremented Revision counter. So an alert processing device only needs to check the alert
entries in the ALC messages to ensure that no ALF message has been lost. In the case
where an ALF message has been lost, the missing message can be requested by sending a
request alert command (see Clause K.2).
The ALC sentence provides condensed ALF sentence information. It contains the identifying
data for each present alert of one certain source/device so that the receiver can understand
which ALF has been missed (and retransmission of ALF can be requested by using the ACN
sentence). It shall be published cyclically at least every 30 s by each alert generating device.
The cyclic alert list transmission shall never stop. When all alerts are in normal state the
cyclic alert list is empty, i.e. the number of alert entries is 0.
The length of this sentence varies with the number of alerts (number of list entries) that are
being generated. In cases where the needed number of entries exceeds the permitted
sentence length the number of sentences is increased.
Alert entry n (see Note 4)
$--ALC, xx, xx, xx, x.x, aaa, x.x ,x.x ,x.x,……..,aaa, x.x, x.x, x.x*hh <CR><LF>
Additional Alert entries (see Note 4)
Revision counter Alert entry 1
Alert instance (see Note 4)
Alert identifier
Manufacturer mnemonic code
Number of alert entries (see Note 3)
Sequential message identifier, 00 to 99 (see Note 2)
Sentence number, 01 to 99 (see Note 1)
Total number of sentences for this message, 01 to 99 (see Note 1)
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