Abstract:
The invention relates to a method for operating an amperometric measuring cell which includes at least a measuring electrode 2 and a counter electrode 3 in an electrolyte chamber 4 filled with an electrolyte. The measuring cell is closed off by a permeable membrane 7 with respect to the measurement sample to be detected. The method of the invention improves the run-in performance of the measuring cell 1. The method includes the step of applying a voltage U.sub.1 across the electrodes (2, 3) during a first time span T.sub.1 starting at a reference time T.sub.0. A reference voltage U.sub.0 is assumed at the start of the measurement and the voltage U.sub.1 is increased relative to the reference voltage U.sub.0.
Abstract:
A gas-measuring device has an electrochemical sensor and features such that the readiness for use is guaranteed for a determined period of time. A status display (7), is activated by the evaluating circuit (3) of the gas-measuring device. The status display (7) displays the degree of depletion of the sensor.
Abstract:
A test adapter for the saturated vapor calibration of gas-measuring devices. The test adapter (2) has, in an adapter housing (15), a peripheral edge (7) for receiving a gas-measuring device and has a depression (10) for receiving the sample liquid in the area of the gas-sensitive surface of the gas-measuring device.
Abstract:
A gas-measuring device has an electrochemical sensor and features such that the readiness for use is guaranteed for a determined period of time. A status display (7), is activated by the evaluating circuit (3) of the gas-measuring device. The status display (7) displays the degree of depletion of the sensor.
Abstract:
A process and device measures and checks concentration values of a plurality of gas components in a gas sample. The distortion of the measuring results by temperature and moisture effects, contamination as well as cross sensitivity and drift phenomena of the sensors of the gas-measuring device is a frequent problem in the measurement of gases by a gas-measuring device. It is possible with the process to recognize implausible measuring results as such on the gas-measuring device without design measures. This is achieved by the evaluation of data of suitably selected calibrating gases, from which a subvector space is constructed in the vector space of all possible measurement data (s1, s2, s3), represented as a plane (E), and a corresponding tolerance range is constructed. If the data (*) determined later during a measurement, are in the tolerance range, they are classified as plausible, and otherwise as implausible. The subvector space is constructed, e.g., such that the sum of the distances of the measurement points belonging to the calibrating gases from the subvector space is as small as possible.
Abstract:
The invention is directed to a method for detecting error sources in an amperometric measuring cell 1 which includes at least a measuring electrode 2 and a counter electrode 3 within an electrolyte chamber 4 filled with an electrolyte solution 6. A permeable membrane 7 closes off the electrolyte chamber 4 with respect to the measuring sample. The method includes the steps of: providing a voltage source 10 outputting a voltage U to apply across the electrodes to generate a sensor current i(t) between the electrodes; starting with the voltage U across the electrodes at a reference voltage U.sub.0 with a reference current i.sub.0, increasing or decreasing the voltage U to a first voltage U.sub.1 during a first time span T.sub.1 ; shortly after the voltage U assumes the first voltage U.sub.1, measuring a first sensor current i.sub.1 and/or, toward the end of the first time span T.sub.1, measuring a second sensor current i.sub.2 ; and, comparing the sensor currents i.sub.1 and/or i.sub.2 to the reference current i.sub.0.