Functional monitoring of an electrolytic gas sensor having three electrodes, and hazard alarm and gas measuring device

An apparatus for the functional monitoring of an electrolytic gas sensor that is sensitive to a specific gas and that has three electrodes including a working electrode, a reference electrode, and a counter electrode, the apparatus comprising:

• a potentiostat for amplifying a differential voltage present between the reference and working electrodes and for regulating a potential of the counter electrode so that the differential voltage becomes as small as possible;
• and
• an electronic processing unit configured to capture a measured current that flows into the counter electrode and that is approximately proportional to a gas concentration of the gas to be detected;
• a transimpedance amplifier for converting the measured current into a measured voltage proportional thereto and said electronic processing unit for capturing the measured voltage then representing the gas concentration;
• said electronic processing unit being further configured, independently of determining the gas concentration, to capture a working voltage, a counter voltage, and a reference voltage respectively present at the three electrodes, in each case to monitor the respective voltage for an impermissible deviation and, in an impermissible case, to output an assigned error message;
• and
• said electronic processing unit being configured to monitor at least one combination of digital values corresponding to two of the measurement, working, counter and reference voltages in each case for another impermissible deviation and in an impermissible case to output same to an assigned further error message.