I've Got My Eye on You

CCTV system's vibration-stopping isolators enhance image and lessen noise

While designing an intelligent closed circuit television system comprised of a miniature dome camera, a motorized drive unit and advanced computerized controls, engineers noticed vibration in the device's chassis during the camera's scanning operation. The Surveyor99, by Vicon Industries, Inc., Hauppague, NY, pans, tilts, zooms and focuses at split-second speeds in automatic or manual modes. The camera can be set to take eight different tours of an area, with 32 different programmable steps, such as responding to an alarm or pausing at a pre-set position.

The vibration hindered image clarity and created noise. Rigid assembly required for the device's accuracy was in fact contributing to its inaccuracy. Two stepper motors, one that directs horizontal pans and another that controls vertical tilts, transmitted vibrational energy at a frequency of 60 Hz to the system's frames through their attachment points.

To solve this problem, designers placed VersaDamp grommets from E-A-R Specialty Composites, Indianapolis, IN, as spacers between the tightly fastened components. Made from an olefinic dynamic vulcanizate, the grommets formed soft connections that stopped unwanted energy from disrupting operation and broadcasting as unwanted sound. Because the material was a damped thermoplastic elastomer, when utilized in a molded isolator, the material controlled the system vibration more efficiently than an undamped isolator, and also reduced the settling time resulting from cycling or start-and-stop operations. Sixteen VersaDamp grommets isolated the two motors and provided rapid energy dissipation to enhance positioning accuracy and picture clarity.

Engineers also took advantage of the fact that the damping performance and durometer could be tuned -- increasing or decreasing hardness as the application required. This was important to the Surveyor camera since it contained two distinctly different stepper motors. With the ability to adjust both damping and durometer of the molding material, they could match the formulation precisely to its use.

--KC

For more information: Circle 527 - E-A-R Specialty Composites or connect directly to their website via the Online Reader Service Program at http://www.OneRS.net/101df-527

Circle 528 -Vicon or connect directly to http://www.OneRS.net/101df-528