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Presently the output is in mV relative to the silver chloride (Ag|AgCl 3M KCl) reference electrode.

We want to report the values relative to the Standard Hydrogen Electrode (SHE), which is by definition, the zero-point of chemical potentials. This will convert our mV readings into Eh (or E0 or e0) values (also in units of mV) and comparable to the output from other Oxidation Reduction Potential (ORP) electrodes.

From PaleoTerra, https://paleoterra.nl/measuring_redox_potential.html, we know that:

The potential of the common Ag|AgCl 3M KCl reference electrode at 20°C equals +213 mV versus the SHE. When the voltage measurement of a redox electrode against the Ag|AgCl 3M KCl reference reads +60 mV, the redox potential equals +273 mV vs. the SHE.

To convert to pE, or the negative log of the e- concentration, according to https://en.wikipedia.org/wiki/Reduction_potential:

we will have the relation pE=16.9 Eh at room temperature.

@fisherba, this may be useful for your work, especially for exploring Eh-pH diagrams, such as https://en.wikipedia.org/wiki/Pourbaix_diagram#/media/File:Pourbaix_Diagram_of_Iron.svg