Assessments - 3, GPA: 5
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Facilidade de uso
It can measure the displacement of remote or inaccessible objects. The camera tracks the motion of the target and provides an analog output proportional to displacement. Custom optics allow a range in the field of view from 0.05” up to several feet. Equipment Supplied One Model 5100 Control Unit One Model 806B Tracking Head One 10’ Interconnecting Cable One Storage/Carrying Case One Standard Lens Set Warnings High Voltage The tracking head and its power supply contain voltages dangerous to human life. These voltages are not accessible during normal operation, but when the cover is removed from either the tracking head or control unit, these voltages are accessible and dangerous. Photomultiplier The tracking tube used in the 5000 Series Displacement Followers is susceptible to damage if subjected to high intensity light. Using the unit outdoors in bright sunshine without stopping down the lens would be an example of use in high intensity light. When changing a lens, avoid direct exposure of the photo tube to intense light sources. If the photo tube should become paralyzed, store the complete tracking head in a dark room for several days. Unless the overexposure has been extreme, the tube will regain its sensitivity. Cable Connections Although the system has been equipped with circuitry to protect it against internal damage, disconnecting the optical head from the control unit while AC power is applied can produce dangerously high voltage on the housing of the optical head. Optical Head Important! Always remove ac power from the system before attempting to disconnect the optical head. Displacement Follower User’s Manual Version 1.4, April 19, 2004 IM1008 Page 1 System Assembly 1 Inspect the equipment for damage that might have occurred during shipment. If you find any damage, notify the shipping company immediately. 2 Attach the interconnecting cable from the control unit to the optical head and secure with the lock ring. 3 Attach the lens systems to the optical head. The lens screws into the extension barrel, and the extension barrel screws into the head. The thread system in the head is a standard Leica, 39mm diameter. Note that the 105mm lens comes attached to the 72mm extension tube. The 72mm extension is factory set and should come set to the correct length. 4 Connect the control unit to a 100-120 VAC, 50/60 Hz power source. Displacement Follower User’s Manual Version 1.4, April 19, 2004 IM1008 Page 2 Theory of Operation The system is a non-contacting electro-optical displacement follower designed to track the motion of a target along any axis. The moving target under study must show a sharp discontinuity in the intensity of its reflected or emitted light. The tracker is, in fact, locking onto that light/dark interface. The lens system focuses the image of the discontinuity onto the photo cathode of an image dissector tube. A simplified drawing of this tube is shown in Figure 1. The backside of the photo cathode emits electrons at a level proportional to the intensity of the projected light. These electrons are then accelerated to refocus on an aperture plate containing a small hole or aperture. This converts the optical image to an electron image, with an electron density proportional to the original light intensity of the target. As electrons enter the small aperture, they are amplified to produce a current output proportional to the number of electrons entering the aperture. Moving the electron image across the aperture plate varies the number of electrons entering the aperture. Figure 1 The system detects change in the photo tube’s output current, and through a servo loop, causes the electron image to refocus on the aperture. The servo loop circuit re-centers the electron image by passing current through coils creating a magnetic field that deflects the electron beam back to its original position. Since the current needed for deflection is directly proportional to the distance that the electron image has moved from center, it acts as a measure of displacement. The actual interface (target) can be moved over the diameter of the aperture by adjusting the reference potential, or lock-on, in the servo loop. If the electron image moves so that fewer electrons are admitted through the aperture, the photo-multiplier output decreases and changes the servo control voltage so that the electron image returns to its original locked-on position. If the image moves in the opposite direction, letting more electrons through the aperture, the servo control is polarized, again returning the image to its locked-on position. Displacement Follower User’s Manual Version 1.4, April 19, 2004 IM1008 Page 3 There are two possible target configurations for measuring target displacement along the vertical axis: light over dark and dark over light. That means it must be possible to alter the phase of the current going through the deflection coils to deflect the electron image back to its original locked-on position and not away ...