Sensor interrogation
A system includes a system housing including an inlet, at least one gas sensor responsive to a first analyte gas other than oxygen within the system housing and in fluid connection with the inlet, and a sensor responsive to oxygen within the system housing and in fluid connection with the inlet. The sensor responsive to oxygen is formed to be chemically separate from the at least one gas sensor responsive to the first analyte gas other than oxygen. The sensor responsive to oxygen is responsive to a change in the concentration of oxygen arising from creation of a driving force in the vicinity of the inlet to provide an indication of a state of a transport path between the inlet of the system and the at least one gas sensor responsive to the first analyte gas other than oxygen.
1. A method of operating a gas detection device including a first amperometric electrochemical gas sensor responsive to a first analyte gas, and a second amperometric electrochemical gas sensor responsive to the first analyte gas, comprising:
operating the first amperometric electrochemical gas sensor in a sensing mode wherein a signal from the first amperometric electrochemical gas sensor is representative of a concentration of the first analyte gas measured by the first amperometric electrochemical gas sensor and in an interrogation mode wherein the first amperometric electrochemical gas sensor is electronically interrogated to test the functionality of the first amperometric electrochemical gas sensor by applying an electric signal to the first amperometric electrochemical gas sensor to simulate the presence of the first analyte gas by generating a current flow between a first working electrode of the first amperometric electrochemical gas sensor and a first counter electrode of the first amperometric electrochemical gas sensor via an electrolyte in ionic contact with the working electrode and the counter electrode without the application of the first analyte gas or a simulant therefor;
operating the second amperometric electrochemical gas sensor in a sensing mode wherein a signal from the second amperometric electrochemical gas sensor is representative of a concentration of the first analyte gas measured by the second amperometric electrochemical gas sensor and in an interrogation mode wherein the second amperometric electrochemical gas sensor is electronically interrogated to test the functionality of the second amperometric electrochemical gas sensor by applying an electric signal to the second amperometric electrochemical gas sensor to simulate the presence of the first analyte gas by generating a current flow between a second working electrode of the second amperometric electrochemical gas sensor and a second counter electrode of the second amperometric electrochemical gas sensor via the electrolyte in ionic contact with the second working electrode and with the second counter electrode without the application of the first analyte gas or a simulant therefor; and
placing the first amperometric electrochemical gas sensor in the interrogation mode only if the second amperometric electrochemical gas sensor is in the sensing mode and placing the second amperometric electrochemical gas sensor in the interrogation mode only if the first amperometric electrochemical gas sensor is in the sensing mode.
2. The method of claim 1 further comprising:
measuring a response of the first amperometric electrochemical gas sensor to the electronic simulation thereof; and
measuring a response of the second amperometric electrochemical gas sensor to the electronic simulation thereof.
3. The method of claim 1 wherein the first counter electrode and the second counter electrode are the same electrode.
4. The method of claim 1 further comprising a reference electrode in ionic contact with the electrolyte and in operative connection with the first working electrode and the second working electrode.