Sperry Marine Rudder Angle Indicator System, Operation, Installaion And Service Manual

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RAIS 056357/B
Alarm Indication 3-1
Chapter 3: Alarms System
3.1 Alarm Indication
The RAC does not contain built-in audible or visible alarm indicators.
To indicate the presence of an alarm, the alarm status output must be
connected to an external device, such as an alarm buzzer or a central
alarm unit, or the RAC must be configured to transmit the alarm state to
an IEC 61162 (NMEA 0183) compliant serial data alarm handling facility.
Alarm Status Output
The “Power Fail. / Gen. Alarm” relay output signals the current alarm
state via a potential-free relay contact pair
1
.
In case the RAC raises an alarm, the output changes from the “no
alarm” to the “active alarm” state.
The output’s logic behaviour may be independently configured as NO
(normally open, closed on alarm) or NC (normally closed, open on
alarm). If the RAC is powered off, the output contacts are open.
Serial Data Alarm Output
The RS-422 output 2 may be configured to transmit alarm status infor-
mation using the $--ALR sentence according to IEC 61162 (NMEA 0183).
When the RAC raises an alarm, an $--ALR sentence is transmitted, con-
taining the corresponding alarm number and description text. The alarm
will be marked as “active” and “not acknowledged”.
When a given alarm condition is no longer present, the RAC transmits
the respective $--ALR sentence once, with the status set to ”acknowl-
edged”. The unit then stops transmitting the sentence in question.
When no active alarms are present, the RAC cyclically transmits a “no
alarms” message as recommended in IEC 80/520/INF. This is an $--ALR
sentence with null fields for the alarm code and description.
CAUTION
Risk of misusage
The ALR sentence as serial output of the RAC is not MED complaint and
therefore NOT allowed as system setting for a ship under wheelmark
certification.
Always make sure that the ALR sentence setting is INACTIVATED when
the RAC is used on a ship under wheelmark certification.
1. A second relay output is provided for future use (“Spare” output), which cur-
rently behaves identical to the “Power Fail. / Gen. Alarm” output. However,
this output may be assigned a different functionality in future software
releases.
Note The operator cannot actively reset the outputs from the “active alarm” to
the “no alarm” state. The outputs will only return to the “no alarm” state
when no alarm condition is present any more.