Array changes after a time

I'm reading a power consumption device with 2 clamps for solar production and my power consumption.
I have good readings and the problem is a array problem. I would like to subtract my Consumption minus solar production.

I have made a join node that gives me an output with 2 arrays (screenshot)
Then I used the node node-red-contrib-calc and there I made a subtraction.

My 2 arrays are called in debug node 0 and 1

So it needs to subtract ARRAY 0 from ARRAY 1 and here is the problem. Sometimes its ok and sometimes it switches ARRAY 1 first and then ARRAY 0 so my result is different.

Is there a way to get array0 always first?

In my dashboard screenshot at that moment it was ok. And when you see the chart you see it switched.

I hope I'm clear...

How have you configured the Join node? If you set it to generate key/value pairs using the topic as the key, and make sure the two incoming messages have different topics, then you will know which one is which.


Have you tried my suggestion to use key/value pairs instead?