(2024-06-30, 05:25 PM)tkurki Wrote: 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.

(2024-07-01, 12:02 PM)Sailoog Wrote:

(2024-06-30, 05:25 PM)tkurki Wrote: 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.

Thanks for the fix and also thanks for the explanation, it makes sense.

I think this issue was not detected before because openplotter-notifications app was not installed by default in previous versions. Also, this app has never been documented and has only been installed by adventurous people.

openplotter-notifications is now installed by default in openplotter v4 and will be fully documented soon. This app will be really relevant from now on.