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Fast laser distance sensor for outdoor applications Product Technology
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The new optoNCDT ILR1171-125 laser distance sensor is used for distance measurements max to 270m and particularly impresses in outdoor measurements. Due to the laser time-of-flight principle with infrared light and a measuring rate of up to 40 kHz, high energy pulses are achieved, allowing stable measurements with very good signal quality. In addition, this better compensates for interfering influences such as fog or rain. The high temperature stability allows applications at temperatures from -40 °C to +60 °C. Thanks to its compact dimensions, the sensor can also be integrated into the smallest installation spaces. |
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What is the functional priciple of optoNCDT ILR2250?
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The optoNCDT ILR2250 is a laser distance measuring device that precisely measures distances in the range of 0.05 m to 150 m without contact. The measurement target can be clearly identified by the red laser measuring point. The maximum range depends on the reflectivity and surface properties of the target.
The device works on the basis of phase comparison measurement. High-frequency modulated laser light is emitted in the process. The light diffusely reflected and phase-shifted by the measuring object is compared with the reference signal. The magnitude of the phase displacement makes it possible to determine the distance to the nearest millimetre.
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The distance measurement can be started in various ways:
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A command can be sent by a PC or another control unit via a serial RS422 interface
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External triggering
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Using the autostart function
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What is the measuring principle of optoNCDT ILR2250?
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Light in the visible wavelength range is modulated with suitably chosen frequencies such that the exact distance can be derived from the multiple of the relevant modulation wavelength contained in the distance to be measured and from the size of the remaining interval. The remaining interval is measured using analogue phase comparison methods. Several modulation waves are used to determine the distance.
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Evaluation of the phase displacement for determining the distance
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SMR - Start of measuring range, minimum distance between sensor and target
EMR - End of measuring range (start of measuring range + measuring range), maximum distance between sensor and target
MR - Measuring range
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What is the measuring principle of interferoMETER?
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The controller uses a spectrometer to convert any light signals that it receives from the sensor. It then calculates distance values using the integrated signal processor (CPU) and transfers the data via its interfaces or the analog output.
Polychromatic white light is generated by an SLED. The light is coupled into an optical fiber.
With a sensor for distance measurement, the light of the fiber is separated by a beam splitter. Part of it radiates a firmly installed reference object. The other part radiates the measurement object. The light reflected by both the reference and measurement object is received by the sensor and conducted into the controller.
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This is followed by the spectral decomposition and radiation of the detector. The light reflected by both the reference object and the measurement object overlaps. The interferometric measuring principle (superposition of waves) is used. Detection of distances and thicknesses is possible with amplification and elimination.
With a sensor for thickness measurement, the reference is omitted. This is why no distance measurement is possible.
Sensor and controller are one unit, as the sensor’s linearization table is stored in the controller.
This unique measuring system allows for highly precise measurement of targets. It is possible to measure both diffuse and reflecting surfaces. For transparent layer materials, thickness measurements can be conducted in addition to distance measurements. Shadowing is avoided because sender and receiver are aligned along one axis.
The excellent resolution and the small beam spot diameter make it possible to measure surface structures. However, measurement deviations may occur if the structure is of a similar size to the beam spot diameter or if the maximum tilt angle is exceeded (e.g., with groove edges).
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Term Definitions
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SMR - Start of measuring range. Minimum distance between sensor surface and target
MMR - Mid of measuring range (=start of measuring range + 0.5*measuring range)
EMR - End of measuring range (=start of measuring range + measuring range)
- Maximum distance between sensor face and target
MR - Measuring range
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Distance sensor IMP-DS, measuring range and output signal at the controller
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Thickness sensor IMP-TH with working distance and operating range
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