Abstract: The invention relates to a sensor for measuring a fluid parameter. The sensor comprises a sensing part for supplying a measurement data signal and a processing part releasably connected to the sensing part. The processing part comprises an identification recognition means capable of recognizing a presence of an identification means in the sensing part. Accordingly in the sensor a particular sensing part used may be recognized so that full functionality can be maintained when exchanging a recognized sensing part and more limited functionality is available when the sensing part is not recognized.

Abstract: The invention relates to a sensor for measuring a fluid parameter. The sensor comprises a sensing part for supplying a measurement data signal and a processing part releasably connected to the sensing part. The processing part comprises an identification recognition means capable of recognizing a presence of an identification means in the sensing part. Accordingly in the sensor a particular sensing part used may be recognized so that full functionality can be maintained when exchanging a recognized sensing part and more limited functionality is available when the sensing part is not recognized.

Abstract: A testing method and apparatus for testing the condition of electrodes and their conductors in ion sensitive measuring or controlling systems, wherein the measuring circuit is disruptive and replaced by an impedance measuring circuit containing only one electrode, so that also failures of, for example, reference electrodes, soiling and deposits, and electrolyte loss, can be determined. The arrangement has sufficient accuracy to detect faults, defects and failures as they slowly come into existence.