Signal K port 8375 - no path data

[Steve J]

Hi

I imagine I have missed something really simple.  Signal K running fine and pulling in data from my NMEA 2000 network.  All instruments showing up fine.  I have installed node red embedded and noticed no data coming in.  As such, I netcat'd to port 8375 and only receive the following data

{"name":"signalk-server","version":"1.39.0","self":"vessels.urn:mrn:imo:mmsi:xxxxxxxxxx","roles":["master","main"],"timestamp":"2021-06-14T15:24:33.529Z"}

I have seen other outputs with path data.

Any direction would be great, many thanks.

SJ

[Teppo Kurki]

There is no default data stream over TCP, you need to subscribe (send a subscription message from the client).

https://signalk.org/specification/1.5.0/doc/subscription_protocol.html

But let me guess: did you install a standalone node-RED and not the plugin version that runs embedded in the server? The embedded nodes work only there.

All in all TCP is not the best way to use SK data, be it from node-RED or other clients.

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[Brian Scally]

As Teppo points out the SignalK embedded Node Red plugin does work well.

If you NEED, for whatever reason, to separate the SignalK server and the Node Red instance...

ie you are not running Node Red embedded in the Signal K server..

Below is an link to an example project for remotely subscribing to the delta stream for "tanks.*" from a non embedded Node Red instance that may give you some ideas of where you not quite getting it to work.

https://github.com/scallybmHome/SignalK-NodeRed--WS-Tanks

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For me ...  I have the SignalK server sitting on the navigation ethernet where it can talk to all the steering, engine, sensors, radar, sonar etc.
The Node red server sits on the house ethernet with things like cabin lights cameras and TVs etc.

Then there would be one hole and one hole only in the firewall between the two.

I will admit to the fact that this is possibly a personal paranoia for keeping the networks separate.
And the fact that the external device initiates the data transfer is a total flaw in the security I know.  BUT...

Brian

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[Steve J]

Hi all

Many, many thanks for the rapid replies.

I have installed the embedded as I couldn't see a reason to use the standalone in my setup.  I only checked port 8375 as I used a path with debug, but cannot see any data coming in from Signal K.  The path is live and data can be seen on the instrument panel in Signal K, but just nothing hitting Node Red.  This path is the level of my water tank.

Many thanks again

SJ

[Teppo Kurki]

I have no idea what you mean by " I only checked port 8375 as I used a path with debug, "

To use Signal K data in the Node RED installed from the server's app store you need just signalk-on-delta or signalk-subscribe nodes. See https://github.com/SignalK/node-red-embedded#available-nodes. No Signal K TCP connection needed.

To view this discussion on the web visit https://groups.google.com/d/msgid/signalk/ff46201d-97eb-4f07-bbd3-2e97f2e5603dn%40googlegroups.com.

[Brian Scally]

Steve J

Here is a simple example in embedded Node Red to obtain vessels.self.tanks.* data.  Filter to a specific $source ( YDEN in my case ) then sort the output to freshWater, blackWater and Fuel.

tanks.*   (.*) is subscription key as this says that the server should send all of the paths in the tanks tree.

The $source filter might not be necessary in your installation and could be specified in the 'subscribe' node. 

I have the NMEA 2K interface ( YDEN-2 ) set up to append the NMEA ID to the NMEA source field, so the value is not consistent.
Also my Victron Venus exports the tank data over the MQTT channel to the SignalK node as well which gives me 2 entries for each tank.

It may be possible to have the subscription node use a wildcard in the $source field.  I have not tried.


Brian

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[{"id":"6e16d9cf.92db78","type":"signalk-subscribe","z":"ef92c9fa.d7d738","name":"","mode":"sendAll","flatten":true,"context":"vessels.self","path":"tanks.*","source":"","period":1000,"x":220,"y":960,"wires":[["4b550988.702b28"]]},{"id":"f72e1225.bee44","type":"debug","z":"ef92c9fa.d7d738","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":740,"y":920,"wires":[]},{"id":"4b550988.702b28","type":"switch","z":"ef92c9fa.d7d738","name":"$source Filter","property":"$source","propertyType":"msg","rules":[{"t":"cont","v":"YDEN","vt":"str"}],"checkall":"true","repair":false,"outputs":1,"x":420,"y":960,"wires":[["fe41a112.bd9b1"]]},{"id":"fe41a112.bd9b1","type":"switch","z":"ef92c9fa.d7d738","name":"Tank Sort","property":"topic","propertyType":"msg","rules":[{"t":"cont","v":"freshWater","vt":"str"},{"t":"cont","v":"fuel","vt":"str"},{"t":"cont","v":"blackWater","vt":"str"}],"checkall":"true","repair":false,"outputs":3,"x":600,"y":960,"wires":[["f72e1225.bee44"],["c5a32ad3.2e6c98"],["219563f.57ca89c"]]},{"id":"c5a32ad3.2e6c98","type":"debug","z":"ef92c9fa.d7d738","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":740,"y":960,"wires":[]},{"id":"219563f.57ca89c","type":"debug","z":"ef92c9fa.d7d738","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":740,"y":1000,"wires":[]}]

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[Steve J]

Many thanks Teppo, I was totally over thinking the problem.  All sorted now :)

[Steve J]

Hi Brian

All sorted now and many thanks.  It was me over thinking and messing up.  Now have alerts and all running :)

All the best

Steve J