Abstract: A heating, ventilating and air conditioning (HVAC) sensor device includes a control signal input for receiving, from an HVAC controller, a control signal for controlling a HVAC actuator, a control signal output for transmitting a control signal to the HVAC actuator; and an electronic circuit, which receives a sensor signal indicative of condensation and/or indicative of relative humidity; and passes through the control signal to the control signal output in response to the sensor signal indicative of condensation and/or indicative of relative humidity being within defined ranges, or overwrites the control signal received at the control signal input with a control reference value and outputs the overwritten control signal at the control signal output in response to the sensor signal being outside the defined ranges. The control reference value causes the HVAC actuator to move an actuated part to a safety position which reduces and/or prevents formation of condensation.

Abstract: A method of communication between a remote computer and Heating, Ventilation and Air Conditioning HVAC devices includes communicatively connecting the HVAC devices to a communication bus via a bus communication interface of each HVAC device, selecting one of the HVAC devices having a remote communication interface as a gateway device, communicatively connecting the remote computer to the remote communication interface of the gateway device, identifying, by the HVAC gateway device, one or more of the HVAC devices connected to the communication bus by retrieving respective identification data of the HVAC devices via the bus communication interface, retrieving, by the gateway device, one or more device profiles corresponding to the identification data of the one or more identified HVAC devices, and enabling, by the gateway device using the retrieved one or more device profiles, data communication between the one or more identified HVAC devices and the remote computer.

Abstract: An HVAC sensor device (50) comprising a control signal input (54in) for receiving control signal(s) for controlling one or more HVAC actuator(s) (10) from an HVAC controller (20); a control signal output (54out) for transmitting control signal(s) for controlling the HVAC actuator(s) (10) and an electronic circuit (56). The electronic circuit (56) is configured to: receive a sensor signal(s) indicative of condensation and/or relative humidity in the HVAC system; pass through the control signal(s) received at the control signal input (54in) to the control signal output (54out) if the sensor signal(s) indicative of condensation and/or relative humidity is within a defined range(s); and overwrite the control signal(s) received at the control signal input (54in) with a control reference value (V1) and output the overwritten control signal(s) at the control signal output (54out) if the sensor signal(s) indicative of condensation and/or relative humidity is outside the defined range.

Abstract: Sensor structure (16) is provided for online monitoring of levels of Furans in oil of a transformer tank. The sensor structure includes a UV light source (26), a filter (30) permitting only UV light of a certain wavelength range to pass, a window (32) permitting the filtered UV light to passes there-through and a UV light detector (36) to receive UV light that passes through the window. When the sensor structure is mounted to the transformer tank that is online so that the window is exposed to oil, and Furans in the oil are being monitored, the Furans will absorb UV light, creating a difference in UV light received by the light detector when compared to the UV light received by the light detector when the monitored oil has no Furans therein. The output signal of the light detector is substantially proportional to a total of Furans in the monitored oil.

Abstract: Sensor structure (16) is provided for online monitoring of levels of Furans in oil of a transformer tank. The sensor structure includes a UV light source (26), a filter (30) permitting only UV light of a certain wavelength range to pass, a window (32) permitting the filtered UV light to passes there-through and a UV light detector (36) to receive UV light that passes through the window. When the sensor structure is mounted to the transformer tank that is online so that the window is exposed to oil, and Furans in the oil are being monitored, the Furans will absorb UV light, creating a difference in UV light received by the light detector when compared to the UV light received by the light de tector when the monitored oil has no Furans therein. The output signal of the light detector is substantially proportional to a total of Furans in the monitored oil.

Abstract: A fiber optic current or magnetic field sensor uses a sensing fiber in a coil for measuring a current or a magnetic field and has a retarder for converting between linearly polarized light and elliptically polarized light. The retardation of the retarder, its temperature dependence as well as its azimuth angle in respect to the plane of the fiber coil are optimized in dependence of the birefringence in the sensing fiber in order to minimize the influence of temperature variations and manufacturing tolerances on the overall scale factor of the sensor.

Abstract: A method is provided for tuning the fiber optic retarder of a fiber optic current sensor towards a desired temperature dependence, the sensing fiber is exposed to a magnetic field or corresponding electric current and the sensor signal as well as the signal's dependence on the retarder temperature are measured. From this initial sensor signal and its temperature dependence, a target sensor signal can be determined, at which the dependence on the retarder temperature equals a desired value. Then, the retarder is thermally treated until the sensor signal reaches the target value. The method obviates the need for repetitively measuring the temperature dependence during the tuning process.

Abstract: A fiber optic current or magnetic field sensor uses a sensing fiber in a coil for measuring a current or a magnetic field and has a retarder for converting between linearly polarized light and elliptically polarized light. The retardation of the retarder; its temperature dependence as well as its azimuth angle in respect to the plane of the fiber coil are optimized in dependence of the birefringence in the sensing fiber in order to minimize the influence of temperature variations and manufacturing tolerances on the overall scale factor of the sensor.

Abstract: A method is provided for tuning the fiber optic retarder of a fiber optic current sensor towards a desired temperature dependence, the sensing fiber is exposed to a magnetic field or corresponding electric current and the sensor signal as well as the signal's dependence on the retarder temperature are measured. From this initial sensor signal and its temperature dependence, a target sensor signal can be determined, at which the dependence on the retarder temperature equals a desired value. Then, the retarder is thermally treated until the sensor signal reaches the target value. The method obviates the need for repetitively measuring the temperature dependence during the tuning process.