Two inputs in a node function

[satkey3]

Hello. I have two inputs in a node function that input random numerical data read from a solar inverter. PV is the instant production of the inverter and Grid is the consumption from the network.
Through that function, I want to do the following::

var Grid = {payload: msg.payload};

var PV = {payload: msg.payload};

if (PV >1.1 && Grid >-0.4)

{ return 1;}

if (PV <0.7 && Grid <-0.4)

{ return 2; }

if (PV >2.1 && Grid >-0.4)

{ return 3; }

if (PV <1.7 && Grid <-0.4)

{ return 4; }

if (PV >2.8 && Grid >-0.4)

{ return 5; }

if (PV <2.5 && Grid <-0.4)

{ return 6; }

else {

return 0 ;}

data 1,2,3 4,5,6 would be sent to a node switch that controls some switches

Unfortunately, I have nothing on the output, something is not right. I'm at the beginning and I can't figure it out.
Maybe someone can help me with the code from the node function. Thank you

[Steve-Mcl]

Messages from multiple wires will never arrive at the input of a node at the same time.

You have 2 options here. 1. Connect everything in series and use alternative msg properties e.g msg.result1 & msg.result2 or use a join node to combine the multiple messages into one.

For your particular scenario, I recommend the series approach.

Note: there are more (and better) approaches however it depends on the modbus addresses you are reading. Here is a document that touches on what I am inferring: Modernize your legacy industrial data. Part 2. • FlowFuse

[satkey3]

Hi, Thank you for the answer. I cannot connect in series the 2 modbus getter node because the huawei inverter dont respond at 2 requests for 2 differently internal address in the same time . So, i used join node to combine the 2 values : PV and grid and it works.- i have the result in one messages debug4

But function still down work:
The fucntion code is oke?

var Grid = {payload: msg.payload};

var PV = {payload: msg.payload};

if (PV.payload >1.1 && Grid.payload >-0.4)

{ return 1;}
else {
return 0 ;}

[Steve-Mcl]

@satkey3

But function still down work:
The fucntion code is oke?

Sorry, no, not at all.

@satkey3

var Grid = {payload: msg.payload};

var PV = {payload: msg.payload};

Why are you creating 2 objects from the same variable? Your screenshot clearly shows the values of interest are in msg.payload.PV and msg.payload.Grid

@satkey3

{ return 1;}
else {
return 0 ;}

An object must be returned (ideally the msg object)

@satkey3

if (PV.payload >1.1 && Grid.payload >-0.4)

This is the only logic part of your function and it can be done in regular nodes (no need for function)

Use 2 switch nodes in series instead:

Join --> switch (msg.payload.PV > number: 1.1) --> switch (msg.payload.Grid > number: -0.4) --> next node

[satkey3]

Yes, i will try with 2 switch but i have 6 contidions and i will need 12 switch

var Grid = {payload: msg.payload};

var PV = {payload: msg.payload};

if (PV.payload >1.1 && Grid.payload >-0.4)

{ return 1;}

if (PV.payload <0.7 && Grid.payload <-0.4)

{ return 2; }

if (PV.payload >2.1 && Grid.payload >-0.4)

{ return 3; }

if (PV.payload <1.7 && Grid.payload <-0.4)

{ return 4; }

if (PV.payload >2.8 && Grid.payload >-0.4)

{ return 5; }

if (PV.payload <2.5 && Grid.payload <-0.4)

{ return 6; }

else {

return 0 ;}

I need a function with one output result ( 1or 2 or 3 or 4 or 5 or6) because after function I have a single switch that controls 3 wireless switches- ex if the function output is 1 first wireless switch is open, if the result is 2 first wireless switch is closed .
So, i need a working function code

[jbudd]

Does this code work for you, assuming that the two values are in msg.payload.PV and msg.payload.Grid?

const PV = msg.payload.PV
const Grid = msg.payload.Grid
let result = 0
if (PV > 1.1 && Grid > -0.4) { result = 1 }
else if (PV < 0.7 && Grid < -0.4) { result = 2 }
else if (PV > 2.1 && Grid > -0.4) { result = 3 }
else if (PV < 1.7 && Grid < -0.4) { result = 4 }
else if (PV > 2.8 && Grid > -0.4) { result = 5 }
else if (PV < 2.5 && Grid < -0.4) { result = 6}
msg.payload = result
return msg;

[satkey3]

Hi
Thank you so much, works like a charm

Here is my final work

and swich

and control device

Best regards guys !

[hotNipi]

I think it takes to test that function before use.

Do some simple test cases like that and see if the output matches your expectations

const PV = 3.2
const Grid = -0.2
//testing for (PV > 2.8 && Grid > -0.4) so expect 5
const expected = 5

let result = 0
if (PV > 1.1 && Grid > -0.4) { result = 1 }
else if (PV < 0.7 && Grid < -0.4) { result = 2 }
else if (PV > 2.1 && Grid > -0.4) { result = 3 }
else if (PV < 1.7 && Grid < -0.4) { result = 4 }
else if (PV > 2.8 && Grid > -0.4) { result = 5 }
else if (PV < 2.5 && Grid < -0.4) { result = 6 }
node.warn("expected: "+expected+' result: '+result)
//msg.payload = result
//return msg;

[bakman2]

@jbudd

else if (PV > 2.1 && Grid > -0.4) { result = 3 }
...
else if (PV > 2.8 && Grid > -0.4) { result = 5 }

Although it works, PV 2.9 would validate to true for both - it is only due to the order that it does not fall through.

[jbudd]

@hotNipi and @bakman2 are right to query that chain of if statements.

@satkey3's original version used return statements, so only one if (... && ...) statement would be evaluated true.
In getting rid of the return statements I used else if (... to hopefully achieve the same result.

A chain of compound if statements like that can quickly become impenetrable.
If I were writing the code myself I'd probably split it into two blocks for Grid > -0.4 and Grid < -0.4
And what happens if Grid === -0.4?

[bakman2]

I would use 2 switch nodes, makes it more clear (in my mind at least)

and then for the pv nodes

something along those lines.

[satkey3]

Hi
Yes, the solution with 2 switch nodes is more easy and clear

Thank you guys!