NMEA2000 has a much broader set of messages dealing with various sensor data then NMEA0183 has. In NMEA0183 there is (beside a small amount of predefined sentences) a more or less generic XDR sentence. As there is no out of the box complete mapping between NMEA2000 and NMEA0183 XDR possible you need to configure the mappings between NMEA2000 and XDR and vice versa.
Typically a NMEA2000 PGN that the gateway can map to an XDR record will belong to a certain category (like Temperature, Pressure, Engine,...), will potentially inlcude a source identifier (like SeaTemperature or OutsideTemperature), an instance id (0...255) and potentially a couple of fields (like EngineOilPressure, EngineCoolantTemp). You now need to select which combination of those values should be mapped to a particular XDR transducer name.
To make the configuration easy the gateway will record information about NMEA2000 PGNs it could in principle map to XDR records - but without a current configuration. Just click "Show Unmapped" to get a list of those entities.
By clicking the "+" button beside the entry you will get a prefilled mapping. You just need to add the transducer name and save the settings.
For the instance Id of a NMEA2000 message there are 3 options on how they can be used to convert to a transducer name:
- single
exactly only this instance id is mapped to the selected transducer name. This should work for most receivers of the XDR records but requires a separate mapping for each of your instances. - auto
In this mode the instance will be added to the transducer name in the form of Temperature#001 - 001 being the instance id. This is recommended in NMEA0183 4.x - but not necessarily received by all devices. - ignore
All instances will map to the same transducer name.
The configured mappings can work in both directions. So when an XDR record with a known transducer name, type and unit is received it is converted into a NMEA2000 PGN. You need to have the direction for the mapping set to "bidir" (the default).
The mappings can be exported and imported as a json file from the UI.
The following PGNS are handled:
| Category | from NMEA2000 | to NMEA2000 |
|---|---|---|
| Fluid | 127505 | 127505 |
| Battery | 127508 | 127508 |
| Temperature | 130310, 130311, 130312, 130316 | 130312 |
| Pressure | 130310, 130311, 130314 | 130314 |
| Humidity | 130311, 130313 | 130313 |
| Engine | 127489, 127488 | 127489, 127488 |
To avoid resending the same XDR transducer to often you can set a minimum delay between sending it again (config/converter/min XDR interval, default 100ms).