Jeppesen Nobeltec Solid State Heading Sensor, Руководство пользователя

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APPENDIX B – NMEA 2000 INTERFACING
Jeppesen Marine
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APPENDIX B – NMEA 2000 INTERFACING
Note:
Jeppesen Marine does not provide technical support for the NMEA 2000
interface as of this printing.
SSHS NMEA 2000 Periodic Data Transmitted PGNs
PGN 127250 – Vessel Heading
The SSHS uses this PGN to indicate the vessel’s heading. The Heading Sensor Reading
(Field 2) includes deviation, therefore Deviation (Field 2) always contains zero. Variation (Field
4) is not provided by the SSHS, therefore, this field always contains a value of 0x7FFF (data
not available). Since the SSHS’s core technology is based on magnetometers, the Heading
Sensor Reference (field 5) is always set to magnetic.
Field 1:
SID – The sequence identifier field is used to tie related PGNs together. For example,
the SSHS will transmit identical SIDs for Vessel Heading (PGN 127250), Attitude
(127257), and Rate of Turn (127251) to indicate that the readings are linked together
(i.e., the data from each PGN was taken at the same time although they are reported
at slightly different times).
2:
Heading Sensor Reading – This field is used to report the vessel’s heading and
includes deviation assuming a deviation table has been successfully loaded through
the magnetic deviation calibration process.
3:
Deviation – The deviation is included in field 2, therefore this field always reads as 0.
4:
Variation – The SSHS does not use this field so the field is transmitted with the value
0x7FFF (data not available). See PGN 127258 for information regarding the SSHS
and its ability to transmit magnetic variation.
5:
Heading Sensor Reference – The SSHS transmits a “1” in this field to indicate that the
heading is referenced to magnetic North.
6:
Reserved – This field is reserved by NMEA; therefore, the SSHS sets all bits to a logic
1.
PGN 127251 – Rate of Turn
The SSHS uses this PGN to indicate the vessel’s rate of turn.
Field 1:
SID – The sequence identifier field is used to tie related PGNs together. For example,
the SSHS will transmit identical SIDs for Vessel Heading (PGN 127250), Attitude
(127257), and Rate of Turn (127251) to indicate that the readings are linked together
(i.e., the data from each PGN was taken at the same time although they are reported
at slightly different times).