Which sensor is forwarded to the server port

Background can be skipped: (While I’ve been working with multiple PCs to exercise/test the cloud layers, I happened across this:

My pc test unit running CE alarmed because the boat wandered into a boundary circle
alarm. Except it shouldn’t have done so, and didn’t.)

I’m (separately) testing multiple GPS units, all connected to the main pc (“helm-pc”).
The “POSN” button allows me to choose which GPS is used on Helm-pc’s navigation (auto disabled). This works as expected. helm-pc is also configured
as a server. A client PC, whose POSN button has selected and reports “GPS on helm-pc” seems correct. However, the position shown on the client wanders to the
tune of a crappy GPS, not matching the position on helm-pc. Searching on helm-pc,
I found another (suspect) GPS that has the wandered position.

So, TLDR, the serving pc listens to its selected GPS and displays same, but
can forward a different GPS to its clients.

Can you dup it? I presume you have a GPS nmea source simulator to exercise this.


We have many GPS NMEA sources, but I’ve not seen the behavior you’re describing.

Would it be possible to remote into your system so we can see your scenario directly? If so, give us a call when it’s a good time for you and we’re open. 7 AM to 5 PM.


Actually, if I understand your setup correctly, this is expected behavior…

I assume by “helm-pc is also configured as a server” you mean you’ve enabled the NMEA 0183 Data Server. That feature acts as a basic NMEA 0183 multiplexer which takes all of the NMEA 0183 input and merges the sentences into a single stream which is sent to the clients bypassing our sensor classification and prioritization settings. That means the clients will receive all of the sentences from all of the devices. Not only do they receive all of the sentences, but it is also sent over a single “port” with no way to identify the source of each sentence, so the client can’t even tell that the GPS sentences came from multiple GPS receivers and therefore can’t perform its own prioritization.

OK, so then how about let the normal mux function, preserving the NMEA
source ID of GP be as is, and take the result of the selection logic and send it as II or EC source ID
or whatever to indicate it comes from CE, not the raw GPS(s). Then the (CE) client
could hopefully display in its button “GPS via helm-pc” and “GPS from helm-pc” or maybe “GPS from GP at helm-pc” and “GPS from II at helm-pc”.
or at worst filters can be applied (can you filter by source ID?)

I guess this is now moved to Enhancement Request from problems/bugs…