Abstract: A feature location and management system having: a user-associated marker unit, including: a controller to generate feature data associated with at least one feature located at a site; an activation device to activate the controller to generate the feature data; and a communication device to transmit at least a portion of the feature data. A central control device directly or indirectly receives at least a portion of the feature data transmitted by the marker unit; and generates display data based at least partially on the received feature data.

Abstract: A gas sensor includes a light source, a power source in operative connection with the light source and a control system in operative connection with the light source and the power supply. The control system is adapted to control power input from the power source to the light source such that the time period of the control frequency is shorter than the thermal time constant of at least one of (i) the infrared light source, (ii) the gas within the sensor, or (iii) a detector of the sensor. The time period of the control frequency can, for example, be no greater than ? of the thermal time constant, no greater than 1/10 of the thermal time constant, or even no greater than 1/20 of the thermal time constant. A feedback signal can be provided to the control system assist in achieving control.

Abstract: A gas sensor includes a light source, a power source in operative connection with the light source and a control system in operative connection with the light source and the power supply. The control system is adapted to control power input from the power source to the light source such that the time period of the control frequency is shorter than the thermal time constant of at least one of (i) the infrared light source, (ii) the gas within the sensor, or (iii) a detector of the sensor. The time period of the control frequency can, for example, be no greater than ? of the thermal time constant, no greater than 1/10 of the thermal time constant, or even no greater than 1/20 of the thermal time constant. A feedback signal can be provided to the control system assist in achieving control.

Abstract: A portable leak detector includes a housing having an inlet and an outlet each in fluid communication between an interior and an exterior of the housing. A gas sensor, having a property that changes in response to exposure of the gas sensor to one or more gases, is positioned in fluid communication with the interior of the housing via the inlet thereof. The leak detector includes a probe lamp, a plurality of first indicator lamps supported by the housing and a speaker supported by the housing. A controller supported by the housing is connected to detect the property of the gas sensor. The controller causes the probe lamp to flash at a first frequency, causes a first group of the plurality of first indicator lamps to illuminate, and/or causes the loudspeaker to chirp at a second frequency all as a function of a detected property of the gas sensor.