Conductivity Sensors & Transmitters

Conductivity Sensors & Transmitters

Conductivity measurement quantifies a liquid’s ability to carry electrical current, providing a direct indication of ionic strength. Conductivity sensors and transmitters are used across wide operating ranges - from ultrapure water monitoring to high-conductivity brines - and are commonly implemented as either conductive (electrode-based) or toroidal/inductive (coil-based) measurement systems.

Conductivity is a foundational parameter for concentration control, water quality verification, product monitoring, and leak or contamination detection. It is frequently applied to track CIP cycle effectiveness, confirm rinse endpoints, detect chemical cross-contamination, and monitor treatment steps where small conductivity shifts are meaningful (e.g., pure/ultrapure water systems).

Conductive sensors apply an alternating voltage across electrodes and measure the resulting current; the conductivity rises with the number of free ions present. At higher ion concentrations, polarization can reduce accuracy, which is why four-electrode conductive designs are used to mitigate polarization effects and extend usable range. Toroidal/inductive sensors use a transmit/receive coil arrangement to couple energy through the liquid without direct electrode contact, making them well-suited for high-conductivity, dirty, or coating media such as acids, bases, and many food & beverage products.

Typical applications include pure and ultrapure water production, boiler and condensate loops, chemical mixing and dosing, brine and caustic service, and hygienic processes such as milk and beer handling. Four-electrode approaches are often selected where a broad dynamic range is required, including process transitions such as phase separation and variable-conductivity product streams.

Engineering considerations include temperature compensation strategy, cell constant verification, fouling risk, and the choice of process connection and materials. Calibration standards and certified cell constants support traceability, while standardized transmitter platforms simplify spares, configuration, and digital connectivity across multiple conductivity points and other liquid-analysis parameters.

George E. Booth Co., an exclusive authorized representative of sales and service for Endress+Hauser.