Rosemount Analytical Inc.

Rosemount Inc.

Behzad Rezvani

Chang-Dong Feng

Hoang Mong Nguyen

Joseph C Nemer

Jeffrey Lawrence Lomibao

Barry W Benton

Calin Ciobanu

James D Kramer

Jung S Hwang

Anni S Wey

Calin I Ciobanu

A colorimetric analyzer includes a reaction chamber configured to receive a sample and at least one reagent. A measurement cell is operably coupled to the reaction chamber. The colorimetric analyzer has an illumination source configured to emit illumination at a first wavelength during a first absorbance measurement and at a second wavelength during a second absorbance measurement. The colorimetric analyzer also includes an illumination detector spaced from the illumination source such that illumination from the illumination source passes through the measurement cell to the illumination detector. A controller is coupled to the illumination source and the illumination detector. The controller is configured to detect an obstruction of light between the illumination source and the illumination detector based on the first and the second absorbance measurements.

Colorimetric analyzer with improved error detection

A method of measuring low conductivity of a liquid sample using a contacting-type conductivity sensor is provided. The method includes applying a first excitation current to a contacting-type conductivity sensor at a first drive frequency. A first voltage response to the first excitation current is determined. A second excitation current is applied to the contacting-type conductivity sensor at a second drive frequency higher than the first drive frequency. A second voltage response to the second excitation current is determined. A conductivity output is provided based, at least in part, on the first and second voltage responses. A system for measuring conductivity of a liquid at or below 100 &#x3bc;S/cm is also provided.

Low-conductivity contacting-type conductivity measurement

A method of measuring impedance of a pH electrode is provided. A test current is applied to the pH electrode for a time duration that is less than 50 percent of a time constant that is associated with electrical characteristics of the pH electrode. A voltage response of the pH electrode is measured when the test current is applied to the pH electrode. An impedance of the pH electrode is calculated as a function of the voltage response.

Impedance measurement of a pH electrode

An improved contacting-type conductivity measurement system and method are provided. A first conductivity measurement is obtained by driving a contacting-type conductivity sensor with an excitation voltage at a first frequency, a second conductivity is obtained by driving the contacting-type conductivity sensor with the excitation voltage at a second frequency. The first and second conductivity measurements are used to provide a more accurate conductivity output.

High-conductivity contacting-type conductivity measurement

An improved flow-through conductivity sensor is provided. The sensor includes a current return path that has a current return conductor. At least one toroid of the sensor is removed from the flow path and configured to interact with the current return conductor to provide an indication of conductivity. Additional aspects of the invention include disposing a pair of toroids about the current return conductor; disposing a toroid about the current return conductor and configuring the toroid as a transformer.

Flow-through conductivity sensor

A pH analyzer is operated to measure conductivity of a solution by applying a substantially DC current having peak values, I , to a reference electrode of an ion-sensitive sensor having an ion-specific electrode in contact with the solution. The reference electrode is coupled to the ion-specific electrode through the solution. The peak voltage, V , between the ion-specific electrode and the common electrode is measured, and the conductivity of the solution is identified based on

Process of measuring conductivity using a pH analyzer

A circuit includes an integrator arranged to integrate input signals over a predetermined sample period based on the cycle period of a power source signal. A delay is coupled to the integrator and is responsive to the end of a sample period to delay start of a successive sample period for a predetermined time delay to cancel low frequency noise induced into the circuit during a prior sample period.

Sensor analyzer with reduced low frequency noise

A pH analyzer is operated to measure pH of a solution by applying a reference electrode current, I , to a reference electrode of a pH sensor and an ion-specific electrode current, I , to an ion-specific electrode of the pH sensor. The currents to the reference electrode and ion-specific electrode are multiplexed to avoid cross-talk. Multiplexing the currents provides a more accurate measurement of electrode impedance for diagnostic purpose. A current spike is optionally added to the reference electrode current to discharge any charge in the solution due to the reference electrode current.

Process for minimizing cross-talk in diagnostic signals of a pH sensor

A inductive conductivity sensor for measuring conductivity of a fluid includes a housing supporting a controlled impedance loop and a transducer. The transducer includes a driver for inducing a first current into the fluid adjacent the housing, and for inducing a second current into the controlled impedance loop. The transducer further includes a detector for inductively measuring the first and second currents.

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Anaheim, CA, United States of America

Behzad Rezvani