Maretron ENGINE MONITORING SYSTEM EMS100 - Manual (Page 19)

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Revision 1.1 Page A1
Appendix A – NMEA 2000
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Interfacing
Note: For integer values, the most positive three values are reserved; e.g., for 8-bit unsigned integers,
the values 0xFD, 0xFE, 0xFF are reserved, and for 8-bit signed integers, the values 0x7D, 0x7E, 0x7F
are reserved. The most positive value (0xFF and 0x7F, respectively, for the 8-bit examples) represents
Data Not Available.
EMS100 NMEA 2000
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Periodic Data Transmitted PGNs
PGN 127488 – Engine Parameters, Rapid Update
The EMS100 uses this PGN to transmit rapidly changing engine data.
Field 1: Engine Instance – (8-bit unsigned integer) This field indicates the particular engine
for which this data applies. A single engine will have an instance of 0. Engines in
multi-engine boats will be numbered starting at 0 at the bow of the boat incrementing
to n going in towards the stern of the boat. For engines at the same distance from the
bow are stern, the engines are numbered starting from the port side and proceeding
towards the starboard side.
2: Engine Speed – (16-bit unsigned integer) This field indicates the rotational speed of
the engine in units of ¼ RPM.
3: Engine Boost Pressure – (16-bit unsigned integer) This field indicates the
turbocharger boost pressure in units of 100 Pa.
4: Engine tilt/trim – (8-bit signed integer) This field indicates the tilt or trim (positive or
negative) of the engine in units of 1 percent.
5: Reserved – (16 bits) This field is reserved by NMEA; therefore, the EMS100 sets all
bits to a logic 1.
PGN 127489 – Engine Parameters, Dynamic
The EMS100 uses this PGN to transmit more slowly changing engine data.
Field 1: Engine Instance – (8-bit unsigned integer) This field indicates the particular engine
for which this data applies. A single engine will have an instance of 0. Engines in
multi-engine boats will be numbered starting at 0 at the bow of the boat incrementing
to n going in towards the stern of the boat. For engines at the same distance from the
bow are stern, the engines are numbered starting from the port side and proceeding
towards the starboard side.
2: Engine Oil Pressure – (16-bit unsigned integer) This field indicates the oil pressure of
the engine in units of 100 Pa.
3: Engine Oil Temperature – (16-bit unsigned integer) This field indicates the oil
temperature of the engine in units of 0.1°K. The EMS100 does not provide a value for
this field.
4: Engine Temperature – (16-bit unsigned integer) This field indicates the temperature
of the engine coolant in units of 0.1°K.
5: Alternator Potential – (16-bit signed integer) This field indicates the alternator voltage
in units of 0.01V.