2024-06-30, 05:25 PM
The visual method for normal state is removed in v3.1.1 of https://www.npmjs.com/package/@signalk/n2k-signalk. As I understand this should fix the issue.
Just a note that this is actually not very new, the mapping from N2K 127489 to Signal K has been like this since 2018.
Since NMEA 2000 has no concept of "state" a device on the bus can just send periodically the same normal/alarm state. PGN 127489 has 2x16 individual alarms that can be on or off, so the simplest strategy for mapping to Signal K is that they are mapped to normal and alarm states.
This way also a UI can know that the notification state is still valid - if there were no subsequent updates you could not tell if the state is still as it should be and the communication path from the device to the UI is still working.
I am surprised that this has not come up earlier.
Just a note that this is actually not very new, the mapping from N2K 127489 to Signal K has been like this since 2018.
Since NMEA 2000 has no concept of "state" a device on the bus can just send periodically the same normal/alarm state. PGN 127489 has 2x16 individual alarms that can be on or off, so the simplest strategy for mapping to Signal K is that they are mapped to normal and alarm states.
This way also a UI can know that the notification state is still valid - if there were no subsequent updates you could not tell if the state is still as it should be and the communication path from the device to the UI is still working.
I am surprised that this has not come up earlier.