I don't understand what you need, and I suspect no one else does.
This section makes no sense:
For example, you show input #2 with 0.9V input, and two different output values.
I didn't read the rest of your post, because I assumed it was related to the above.
Read the rest of the post and maybe it will make sense to you.
Ok, I'll break it down for you.
You've got an Oxygen sensor (Input #1) , it creates a voltage through a chemical reaction, this voltage varies between .1V and 1.0V depending on the oxygen content of a gas stream (stream #1).
I've got a "piggyback" that modifies the voltage from this sensor depending on several variables. (Controller scale), and outputs it (Output #1)
This is all fine and dandy, everything works great.
Now, here's the problem:
I also have 3 more oxygen sensors (Input #2, Input #3, Input #4) that are each in their own separate gas stream.
Hence the voltages from all inputs are almost never the same. 4 sensors, 4 locations, 4 different voltages. But they all follow the same "range" of .1V to 1.0V
I need to build a circuit that can take Input #1 and subtract it from Output #1 (using a differential OP Amp?) to get the voltage "difference" .
Follow me?
Now I need to take this "difference" and add it to each of the other sensor values.
Make sense now?
If Input1= .2V and Output1=.2V then the difference is 0, all signals stay the same.
If Input1=.2V and Output1=.5V then the difference is .3V, all signals need to have .3V added to them.
If Input1 = .2V and Output1=.1V then the difference is -.1V, all signals need to have -.1V added to them (in effect they all need to drop in voltage by .1V).
Easier to understand?
John