METER data loggers (ZL6, EM50/60 series, Em5b) or any data acquisition systems capable of switched 2.5–3.6 VDC excitation and single-ended voltage measurement at greater than or equal to 12-bit resolution.
NOTE: These calibration constants only apply to 2,500-mV excitation; use of these numbers with any other excitation voltage results in erroneous readings!