Abstract: A system including one or more gas sensor assemblies having one or more gas sensors. The gas sensor is for sensing a preselected gas. The gas sensor assembly includes a housing with a cavity therein, and the sensor is mounted on the housing so that the sensor is able to detect the preselected gas in the cavity. The gas sensor assembly includes a sensor control module in communication with the gas sensor, and also in communication with a central controller. Via the central controller, the sensor may be tested using a purge gas, and the sensor may be zeroed if necessary. Also, via the central controller, the sensor may be calibrated using a calibration gas mixture having the preselected gas in a known concentration. The central controller is configured for manual or automatic testing and calibration. Accordingly, the testing and calibration, whether manual or automatic, is done remotely.

Abstract: A system including one or more gas sensor assemblies having one or more gas sensors. The gas sensor is for sensing a preselected gas. The gas sensor assembly includes a housing with a cavity therein, and the sensor is mounted on the housing so that the sensor is able to detect the preselected gas in the cavity. The gas sensor assembly includes a sensor control module in communication with the gas sensor, and also in communication with a central controller. Via the central controller, the sensor may be tested using a purge gas, and the sensor may be zeroed if necessary. Also, via the central controller, the sensor may be calibrated using a calibration gas mixture having the preselected gas in a known concentration. The central controller is configured for manual or automatic testing and calibration. Accordingly, the testing and calibration, whether manual or automatic, is done remotely.

Abstract: A method of determining a velocity of air flowing in an air flow direction through an opening. The method includes locating first and second transducer assemblies in the opening, to position the first and second transducer assemblies spaced apart by a predetermined distance along a substantially straight line of sight defining a non-zero angle in a horizontal plane between the line of sight and the air flow direction. A controller is operatively connected with the first and second transducer assemblies respectively, via a four-wire interface in which two of the wires are for power transmission and two of the wires are for transmitting signals. The transducer assemblies are time-synchronized. First and second electronic signal pulses are transmitted between the first and second transducer assemblies. Based on the transit times, the non-zero angle, and the predetermined distance, the velocity of the air flowing in the air flow direction is determined.

Abstract: A system for determining a velocity of air flowing in an air flow direction through an opening. The system includes first and second transducer assemblies with first and second transducers. The first and second transducers are positioned in respective predetermined first and second positions in which the first and second transducers are intervisible. The first and second transducers are disposed at respective selected tilt angles when in the respective predetermined first and second positions. Each of the first and second transducer assemblies includes means for measuring respective measured tilt angles of the first and second transducers. The system also includes a controller configured to compare the measured tilt angles to the selected tilt angles for the first and second transducers respectively, to determine whether there are measured differences therebetween exceeding a predetermined permitted difference.

Abstract: A system for determining a velocity of air flowing in an air flow direction through an opening. The system includes first and second transducer assemblies with first and second transducers. The first and second transducers are positioned in respective predetermined first and second positions in which the first and second transducers are intervisible. The first and second transducers are disposed at respective selected tilt angles when in the respective predetermined first and second positions. Each of the first and second transducer assemblies includes means for measuring respective measured tilt angles of the first and second transducers. The system also includes a controller configured to compare the measured tilt angles to the selected tilt angles for the first and second transducers respectively, to determine whether there are measured differences therebetween exceeding a predetermined permitted difference.

Abstract: A method of determining a velocity of air flowing in an air flow direction through an opening. The method includes locating first and second transducer assemblies in the opening, to position the first and second transducer assemblies spaced apart by a predetermined distance along a substantially straight line of sight defining a non-zero angle in a horizontal plane between the line of sight and the air flow direction. A controller is operatively connected with the first and second transducer assemblies respectively, via a four-wire interface in which two of the wires are for power transmission and two of the wires are for transmitting signals. The transducer assemblies are time-synchronized. First and second electronic signal pulses are transmitted between the first and second transducer assemblies. Based on the transit times, the non-zero angle, and the predetermined distance, the velocity of the air flowing in the air flow direction is determined.