Hello, I use a digital pressure sensor in my irrigation system. Unfortunately, its measurement results are not linear. I have to adjust the values mathematically. I can't get any further with the "range node". Is there maybe another node that I could use. The problem, the correction factors are no…

Hello Pinie_Pinie, You can work with a normal function node and put in a switch case function, but this makes maybe only sense, if that are all values: var value = msg.payload; switch (value) { case (0): value = 0.6; break; case (0.6): value = 2.69; break; case …

What interpolation accuracy do you need and what accuracy is the device specified at? Also how often are you looking up the values?

Hello, thank you very much first of all. A good approach. I explained that badly. The correction should be made in one area. e.g. 0 - 2.3 = 0 or 2.4 - 2.7 = 0.6 etc. My digital sensor is showing values that are too high. If I have understood that correctly, an area should be defined in the funct…

If it doesn't need to be extremely accurate what problem did you have with the Range node? This should do what you want [image] So an input of 2.3 or below will give you 0, an input of 6.18 or above will give 6.2, and it will be scaled linearly in between. That gives a max error of 0.17 in the o…

[image] Ranki: var value = msg.payload; switch (value) { case (0): value = 0.6; break; case (0.6): value = 2.69; break; case (1): value = 2.83; break; … default: return null; // or errorhandling break; } Hi Pinie_Pinie, Ran…

Hello, I can't get this thing to work Sorry I'm missing something. I have two Incjet.Nodes at the entrance with 1 and 2.5. The node is currently doing nothing. It comes out 1 or 2.5 at the end. The fault is definitely mine. Thank you for your patience [Node]

Why don't you like the range node technique, which will give you the correct value which you can then easily compare with your limit? Also it saves writing javascript, which is easy to get wrong.

I agree with Colin the range node should work fine here. As to your code you are setting value but I see no setting of value to a msg property.

[image] Colin: Why don't you like the range node technique, which will give you the correct value which you can then easily compare with your limit? Also it saves writing javascript, which is easy to get wrong. Hello, you're right. I just tested the Rangenode with your settings and it works …

[image] pinie_pinie: I don't understand the exact logic behind the node, but it doesn't matter. It does matter, you should never use a node unless you basically understand what it does. The settings I posted tell it to expect a message payload input between 2.3 and 6.18. It says if it is 2.…

Adjust values from the pressure sensor with Node?

General

Ranki 15 May 2021 14:30 13

Hello Pinie_Pinie,

It‘s good to know that you are now fine with the change node. Nevertheless to complete the function node thing here:

Of course there is missing the assignment to the payload again like the following; my script was only to give you an example how it would work.

msg.payload = value;

Cheers
Ranki

Topic		Replies	Views
Range node - non linear General	36	1538	1 April 2022
Correct the values of a measurement General	6	418	26 August 2020
Unterschiedliche Ausgabe bei function Dashboard	7	692	8 November 2022
Gas smoke sensor MAX6675, pressure sensor, arduino and raspberry pi General	13	2961	14 January 2019
Help with function node and multiple inputs General node-red-dashboard , function-node	17	3331	18 September 2022

Adjust values from the pressure sensor with Node?

Related topics