Maretron SSC200 - Manual (Page 33)

Revision 1.8 Appendix B – NMEA 2000
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Interfacing Page B1
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Appendix B – NMEA 2000
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Interfacing
SSC200 NMEA 2000
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Periodic Data Transmitted PGNs
PGN 127250 – Vessel Heading
The SSC200 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 SSC200, therefore this field always contains a value of 0x7FFF (data not
available). Since the SSC200’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 SSC200 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 SSC200 does not use this field so the field is transmitted with the
value 0x7FFF (data not available). See PGN 127258 for information regarding the
SSC200 and its ability to transmit magnetic variation.
5: Heading Sensor Reference – The SSC200 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 SSC200 sets all bits to a
logic 1.
PGN 127251 – Rate of Turn
The SSC200 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 SSC200 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: Rate of Turn – This field is used to report the vessel’s rate of turn.
3: Reserved – This field is reserved by NMEA; therefore, the SSC200 sets all bits to a
logic 1.
PGN 127257 – Attitude
The SSC200 uses this PGN to indicate the vessel’s attitude (pitch and roll). The Yaw (field 2)
is not used, therefore this field always contains 0x7FFF (data not available).
Field 1: SID – The sequence identifier field is used to tie related PGNs together. For example,
the SSC200 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).