Morning all,

I'm trying to figure out how the 1-10v logic interacts with the pH. I was hoping that the analog voltage would be linear based on the pH reading but when I probe the 1-10v and ground on the L port of the break out box and place the pH probe in various solutions the output voltages doesn't make sense.

I also realize that "Nominal value" and "Hysteresis" change how the 1-10v reference is read. I have read this article by @sibylle and tried to apply the temperature explanation to pH but there are more questions than answers.

Let me give you a brief run down of what I'm trying to accomplish. I have an arduino that I want to read the pH from the GHL in the format of 0-5v so that I can take that signal and give it a value so that the arduino can take action based on pH. But I don't know the limitations of how the profilux sends this signal and how changing the "Nominal value" and "Hysteresis" effect the value.

My hypothesis is that "Nominal value" is the 0 point and as I move away from the "Nominal value" the voltage increases. If this is true, does it increase the same in both directions? And how does "Hysteresis" play a role in the output? What pH range do you get the full 0-10v reference?

I'm not sure if this is something that has been addressed in previous threads, if it has, I couldn't find anything. Can someone point me in the right direction with information on the subject?