how does pH signal processing work?

[mbudde]

For my project, I need to use a different pH probe than the one provided and need to make sure it is quite accurate. The pH probe I will be using outputs a high impedance signal +/- 0.5v. I was planning on amplifying and shifting the signal with a TI INA116, to output 0-5 so I could input it into the arduino. I'm curious what amplification is included in the unit? Because if it is a good amplifier, then I wouldn't need to change my hardware.
Thanks!

[rimai]

You can download the eagle files for the electrical and design drawings.
It uses CA3140A and LM741.

[mbudde]

Thanks Roberto. I downloaded the eagle files but have never read them before so I was a little lost. I think I will go ahead and just try to wire up my probe. Thanks for making everything so easy!