Sperry Marine 5016-CA, Operation, Installaion And Service Manual

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056376/A Analogue Compass Repeaters
2-2 Powering up the Repeaters
2.2 Powering up the Repeaters
The analogue compass repeaters are not equipped with power
switches. The devices power up as soon as supply power is applied.
2.3 Data Protocol and Source Detection
When it is first connected to the gyrocompass system, the repeater
auto-detects the communication parameters by checking for a valid pro-
tocol/baudrate combination in the following order:
• NMEA 0183 at 4800 Bd.
• NMEA 0183 at 38400 Bd.
• NMEA 0183 at 9600 Bd.
• NMEA 0183 at 19200 Bd.
• Plath binary format (9600 Bd.)
Once the repeater has recognized valid data, it stores the communica-
tion parameters and will re-activate them at subsequent power-ups to
become quickly operative. Should no data be recognized using the
stored communication parameters, the repeater executes the auto-
detection routine again.
Within a standard Sperry Marine NAVIGAT gyrocompass system, the
analogue repeater will receive the heading source selection status from
the compass system.
If the NMEA 0183 protocol is used, the repeater evaluates the proprie-
tary $PPLAN or $PPNSD sentences. If the PLATH protocol is used, the
heading data itself contains a source indicator.
In systems where the NMEA 0183 protocol is used but no $PPLAN or
$PPNSD sentences are received, the repeater determines the active
source by searching the incoming data for valid heading sentences in
the following order of priority:
• $HETHS (source = GYRO)
• any $--THS, except $GPTHS (source = GYRO)
• $HEHDT (source = GYRO)
• any $--HDT, except $GPHDT or $HCHDT (source = GYRO)
• $GPTHS (source = THD)
• $GPHDT (source = THD)
• $HCHDT (source = MAG)
• $HCHDM (source = MAG)
• $HCHDG (source = MAG)
Should the currently active heading source get lost, a timeout condition
will occur, the compass card may freeze and the repeater will search the
incoming data for other valid heading sentences in order of priority.
Note
The communication protocol and baudrate may be hard-set in the
repeater configuration. This will disable auto-detection.
Note
The range of recognized sentences for each source may be restricted by
hard-setting the accepted sentences in the repeater configuration.