PMI-201X Potassium Ion Selective Electrode

A potassium ISE develops a membrane potential related to potassium-ion activity. Calibration relates this response to the stated concentration scale. It is not a conductivity measurement, and temperature compensation alone does not correct all changes in ionic strength or interfering ions.

Calibrate for the sample

• Use the supplied conditioning and calibration procedure with appropriate potassium standards. Verify the result with a separate reference sample on the same reporting basis.
• Review competing ions, particularly ammonium and other cations listed in the supplied electrode selectivity data. High selectivity does not mean immunity to other ions, especially at low potassium concentration.
• Assess pH, ionic strength, sample composition and fouling. Any ionic-strength adjustment, dilution or extraction must follow a validated method; do not assume that every sample needs no preparation.
• Juice, wine, milk, fertilizers and soil extracts require their own preparation and materials assessment. An aqueous-sample electrode is not automatically suitable for direct insertion into every food, solid or concentrated chemical product.

Install and maintain PMI-201X

• Confirm the selected range, wetted materials, mounting, pressure and temperature limits, power and receiving-device compatibility for the ordered version.
• Follow the supplied cleaning, conditioning and storage instructions. Do not apply a blanket keep-dry instruction to the sensing membrane or reference system.
• Track reference checks, drift and response after cleaning or replacement. Set maintenance intervals from actual sample conditions and the electrode documentation.
• The listed RS485 Modbus RTU connection is digital. Match wiring, supply, serial settings, register units and invalid-reading behaviour to the controller or logger.