Can't add values

[afelix]

Dag Ronald,
even in het Nederlands voor de snelheid. Je numerieke waardes staan als tekst opgeslagen. Zie de quotjes aan beide kanten. Om er mee te rekenen moet je ze naar nummers overzetten. Ik zoek er even een forum post bij waar ik dit een paar dagen geleden heb uitgelegd
Zie het tweede deel van de volgende post:

Splitting data from msg.payload

Okay, then I'll spoil you with the solution, with an explanation on the how (I'm sick and bored and that's the excuse I'll use for it today :P): What you're going to need is a function node, after your serial node. From what I remember from seeing this node, there is a configuration option that lets you trim off the whitespace, by selecting the return type or something like that. If it's there, select carriage return line feed or enter \r\n if it is an input. If it's not present there, you will…

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Summary in English: your values are stored as string values rather than numbers. To use them for calculations you have to turn them into numbers first.

1. for a whole number, an integer: msg.payload = parseInt(msg.payload, 10); // 10 as in base 10, a decimal number
2. for a decimal number, or rather a floating point: msg.payload = parseFloat(msg.payload);
3. if you don't know if it's a decimal or whole number, or if you want it to fail if there's still text in it: msg.payload = Number(msg.payload); If it has any text in it that makes it's unable to get a number, you will get NaN instead: Not a Number.