Venting protects enclosed electronics in attitude sensor

Gore Protective Vent prevents condensation in the Sunsight Instruments AntennAware Attitude Sensor. The sensor uses time of day, latitude and longitude information to determine solar positioning, to +/-2˚ of accuracy. High-sensitivity accelerometers measure down-tilt and antenna plumb to within +/-.25˚ accuracy.

08/28/2010


With and without: After five months of exposure to sun, rain, and snow, the AntennAware Attitude Sensor (AAS) from Sunsight Instruments with the Gore Protective Vent (left) showed no evidence of condensation, while the AAS without a vent (right) showed substantial condensation.Sunsight Instruments uses Gore Protective Vents to eliminate condensation in its AntennAware Attitude Sensor (AAS), a permanently mounted or fully integrated monitoring sensor to ensure the ongoing correct alignment of antennae. Sunsight Instruments of Orlando, FL, provides Antenna Alignment Solutions and monitoring systems to the telecommunications industry.

The sensor uses time of day, latitude, and longitude information to determine solar positioning, which is used to measure azimuth to +/-2˚ of accuracy. High-sensitivity accelerometers measure down-tilt and antenna plumb to within +/-.25˚ accuracy. The sensor can conduct accurate climbless audits and to provide alerts of misalignment conditions saves thousands of dollars for telecom operators and enhances the safety of their operations. In addition, operators have accurate alignment information for planning, ensuring efficient market coverage.

To prevent condensation and ensure accurate readings, Sunsight incorporates a membrane vent within each AntennAware protective enclosure.  The vent equalizes pressure within the dome by allowing air to pass in and out of the enclosure. It provides a barrier to prevent liquid, dirt, dust, salt and other contaminants from entering while it also reduces condensation.

Measurements made by the AntennAware are non-relative. They reference two constant sources of orientation— the force of gravity and the orbit of the earth around the sun. Obviously, this requires that the instrument be able to track the movement of the sun across the sky without any obstruction or distortion through the protective clear dome that covers it. 

Exposure to the elements puts the AntennAware at risk for condensation within the clear dome, which heats up in the sun and then cools rapidly when hit by rain or snow. This creates a vacuum within the enclosure that can stress the seals and draw moisture inside. Typical seals can begin to draw in moisture and contaminants at about 1.0 psig. Condensation formation within the dome has the potential to obstruct sunlight entering the clear dome, resulting in fewer azimuth measurements being provided to Sunsight’s clients. Moisture within the dome can also corrode the sensitive electronic instrumentation that is being protected.

Gore Protective Vents employ membrane technology used in telecom equipment, lighting enclosures, portable electronic devices, medical devices, and chemical packaging. Vents are made of expanded polytetrafluoroethlylene (ePTFE). Their porous microstructure allows air to flow freely, thereby quickly reducing condensation. Their extremely low surface tension causes them to rapidly shed water and other liquids, including acid rain, cleaning agents and oils, Gore says.

www.gore.com/protectivevents

www.sunsight.biz/Portfolio.aspx

Also read:

Venting about enclosure design

System Integration Channel on Control Engineering

Sensors New Products area on Control Engineering

- Edited by Mark T. Hoske, Control Engineering, CFE Media, www.controleng.com



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