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Electronic Self-Leveling Isolation System
Benchtop Isolation System
The PWA090 electronic, self-leveling, vibration isolation system provides a portable, lightweight, low-profile, vibration-control solution for sensitive benchtop equipment and experiments. The system consists of four pneumatic isolators that must be connected to a constant supply of air, either from a compressor or bottled air supply, and an electronic control box with keypad. Other isolator quantities are available upon request.
The control box, which is shown in the image to the right, houses three proportional valves, each controlling a master isolator. The fourth (slave) isolator is controlled by one of the three master legs. Control of these valves is via a PID control loop that provides feedback for the leveling system. This electronic sensing system removes the need for the mechanical linkage between the valve and the breadboard found on traditional systems and results in more efficient isolation. Manual adjustment of the level/height is achieved via a keypad. Once set up, the level is maintained and any further disturbances are corrected automatically. These miniature electronic isolation mounts are only 110 mm (4.33") in diameter and 71 mm (2.8") high, making them ideal for use with breadboards and small optical tables.
The system is designed to be used on a desk, benchtop, or similar surface. The isolators can be used free standing to provide a temporary or moveable isolation solution. Alternatively, they can be bolted to an imperial or metric tapped work surface for more permanent applications. These isolators can also be used to upgrade a PFR series rigid frame to have active isolation as shown in the photo to the right.
These supports contain an isolation system that effectively isolates the worksurface from vertical and horizontal vibrations within the critical 3 - 50 Hz frequency range, which is the range where most common large-amplitude sources of vibrations are found in laboratories (see the Optical Tables Tutorial tab on Sources of Vibration). The vibrations are isolated from the breadboard by an air-driven pneumatic isolation system. This proprietary design eliminates the need to use oil-based damping systems that can leak or degrade over time. The supports are controlled by a control box, which regulates the pressure in the pneumatic system to control the height of the breadboard. If the breadboard is displaced vertically, the control box changes the pressure in each isolator as necessary, so that the breadboard is returned to its original height.
In order to avoid system oscillation or long settle times, the mounting surface must be flat to within 4.0 mm.
Vertical Transmissibility Plot
A vibration isolation system is subjected to continuous vibrational impulses from the laboratory floor. These vibrations may be caused by large machinery within the building or even by wind- or traffic-induced building resonances (swaying). Transmissibility is a measure of the isolator's efficiency at damping out these vibrations and is defined as the ratio of the amplitude of the transmitted vibration to that of the forcing vibration.
Typical Weight/Pressure Settings