![]() ![]() For this reason, the retroreflective mode is also a reliable sensing mode, even if the target’s color or finish is inconsistent. Like opposed-mode sensing, retroreflective sensing is also a beam-break mode, so objects can often be detected regardless of their reflectivity. Retroreflective-mode sensors offer relatively long ranges. For example, a retroreflective-mode sensor offers a convenient alternative to opposed-mode if electrical connections are only possible on one side. If an opposed-mode sensor is not an option, a retroreflective-mode sensor may be a good choice. Most corner-cube retroreflectors resemble bicycle reflectors and are molded using clear acrylic plastic, manufactured in various sizes, shapes, and colors. In this way, the retroreflector returns the light beam to its source. A light beam enters a corner cube prism through its hypotenuse face and is reflected from the three surfaces. ![]() Most retroreflectors are made up of many small corner-cube prisms. As with an opposed-mode sensor, an object is sensed when it interrupts or "breaks" the effective beam. The effective beam is established between the emitter, a retroreflector, and the receiver. Unlike an opposed-mode sensor, a retroreflective sensor contains both the emitter and receiver elements in a single unit. Therefore, variables such as surface reflectivity, color, and finish don't affect opposed-mode sensing. The object physically passes between the emitter and receiver and is detected when it blocks the beam of light. It doesn't matter how shiny or dark your object is, or even what color. Opposed-mode sensing offers much higher excess gain than any other mode of sensing, making it ideal in dusty, smoky, foggy, misty, or oily environments. An object must be the diameter of the effective beam or larger to be reliably detected.īecause the light beam goes directly from the emitter to the receiver and doesn’t have to reflect off of anything, opposed-mode sensors have very high excess gain. The diameter of the effective beam is the same diameter as the lenses of the emitter and receiver. An object is detected when it breaks the effective beam, which is the column of light directly between the emitter’s lens and the receiver’s lens. This is because light passes directly from the emitter to the receiver. The opposed mode should be used whenever possible because it is the most reliable sensing mode. The emitter is placed opposite the receiver so that the light beam goes directly from the emitter to the receiver. In opposed-mode sensing, also known as through-beam sensing, the sensor's emitter and receiver are housed in two separate units. Snap Signal lowers your barrier to entry for IIoT. ![]()
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