Calculate nmea values and create new value

[DerTom1978]

Hello Community,

I would like to calculate amps and volts to watts.
My Cerbo GX only outputs amps and volts, I would like SignalK to also display watts.

Is there a plugin or another way that will multiply, add, subtract the existing ...and so on?

Greetings and thanks for your help
Tom

[sbender9]

Take a look at the node-red plugin?

[DerTom1978]

The plugin alone is not a solution.
As far as I know, the complete node-red server must be installed for it to work.
For a simple calculation task a bit oversized ...

[tkurki]

”The complete node-RED” provides a UI to create the calculations you need in a user friendlish format. Installing it is one click in the app store. Resource consumption wise it is negligible.

I am not aware of any other solution for generic calculations.

Of course you can roll your own plugin if the existing solution doesn’t appeal to you.

[DerTom1978]

i have installed node-red now.
But I have very little experience with node-red.
i come from the iobroker world :-)

How do I multiply 2 values in node-red?

Greetings
Tom

[tkurki]

There are plenty of resources for learning Node-RED, I think you are better off just googling for tutorials and learning Node-RED than asking for very specific help here.

[sbender9]

True. But you might find it useful for other things.

derived-data plugin can calculate battery power https://github.com/SignalK/signalk-derived-data/blob/master/calcs/batteryPower.js