question

vassilis-bourdakis avatar image
vassilis-bourdakis asked

NodeRed: NMEA2000 -> SignalK -> NodeRed use?

hello and a happy new year to all!

had some time over the festive period to try nodered (unsuccessfully) so a couple of I think basic Qs that I seem to have missed - as a nodered newbie .

Right, so got my system on a rpi3B+ running now for almost two years. Currently on 2.91 Large, NMEA2000 data going nicely into signalK influx grafana, all that done no probs.

Now I'm trying to at first read some of that data in nodered and hopefully use them to send N2K PGNs to the bus to do certain things (first easiest one is start stop the generator but seems to be a bit too far away atm).

So I have this data in signalk (that's on a twin screw mobo and that's the third motor of the generator hence .2 which is fitted with various electronics and I'm monitoring rpm, oil/seawater/fuel pres, coolant temp, engine Status, etc):

1672729902126.png

and for starters let's say I want to read the propulsion.2.Governor value in node red, so I do:

1672729966135.png

and from what I gathered, I should use vessels.self in context, the signalk string in Path and god knows what in $Source. I've tried various options suggested and decided to settle for the Source mentioned by singalk. To no avail. No debug errors nothing.


for what it's worth I'm using the venusOS embedded nodered where I've installed the signalk bits. So on venus I only get two tabs and not three as I've seen in a couple of posts in here. I assume that's fine as I'm running the 2.91ver but I may be wrong?

1672730616184.png


so any pointer welcomed!


cheers

V.

Node-REDSignalK
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1 Answer
Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

@Vassilis Bourdakis

First thing that comes to mind is that the Signal K nodes only work in Signal K embedded Node-RED (need to install from the app store and then run it as a web app to avoid conflicts with the Venus embedded Node-RED).

Re the two tabs, you'll get the 3rd tab (open Node-RED in safe mode) with Venus OS 3.0 (or 3.00~14 beta).

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vassilis-bourdakis avatar image vassilis-bourdakis commented ·

@Stefanie thanks, so it's not yet all integrated into one then.

OK, let me get all that installed and figured out and will come back tomorrow for more :-)

cheers

V.

PS. a couple of working examples would be a nice have to help newcomers into this node-red confusion!

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Stefanie (Victron Energy Staff) avatar image Stefanie (Victron Energy Staff) ♦♦ vassilis-bourdakis commented ·

I've asked Signal K developers to convert the nodes to work with any Node-RED installation, but there are other priorities. And since there is no compelling reason for it (because you can simply use Signal K embedded NR instead of Venus OS 'embedded' NR), this will probably never happen.

There are so many examples of Node-RED flows out there, I don't think it's necessary to reinvent the wheel, just google it ;-)


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vassilis-bourdakis avatar image vassilis-bourdakis commented ·

hm, wasn't that difficult finally, got it running with the full $Source value (MiToS-N2K.138) on the signalk app store installed signalk-node-red plugin by Scott!

next step is go to the boat with the laptop and try to send the engine start NMEA2000 PGN and see what happens :-)

thanks a lot!

V.

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