Laser displacement sensor selection method – Turck

1. Pay attention to the structure and data of the measured object, and the measurement of the general laser displacement sensor requires a complete triangular optical path. If the object to be measured has deep grooves or messy appearance, the triangular light path may be obstructed, making it impossible to measure. There are also some light-absorbing materials, such as black rubber and other materials, most of the light intensity will be absorbed, so it is necessary to adjust the exposure time reasonably to obtain sufficient measurement signal. In addition, strong reflection or specular reflection of the measured object may cause the light to return straight without diffuse reflection, which will also lead to poor measurement effect. Therefore, when using laser displacement sensors, it is necessary to communicate with the manufacturer first, and do not take it for granted that it can be measured by humans, but the results are not good. At present, international mainstream laser displacement sensor brands, such as Miiridium in Germany and Keyence in Japan, will require customers to inform the appearance structure and reflective characteristics of the measured object in advance when selecting laser displacement sensors. If it is a special test material, such as glass, rubber and dark lines on the surface, it may be necessary for the user to provide samples for trial testing to ensure that the measurement requirements are met before ordering.

Laser displacement sensor selection method – Turck

Laser displacement sensor selection method – Turck

2. Parameter selection, many manufacturers provide multiple levels of laser displacement sensors for customers to choose. The target commonly used to select laser displacement sensors includes the accuracy of the sensor, which also has other designations such as linearity, absolute error, etc. It refers to the degree of error that the measured value of the sensor contradicts the theoretical real value. This parameter directly reacts to the accuracy of the measurement. The second is resolution, which refers to the minimum displacement change required by the sensor to change the number of displays, and the general resolution parameter value is less than the accuracy. The third is the measurement speed, taking the Germany Miiridium optoNCDT as an example, its measurement speed can reach 49kHz, and the measurement speed directly determines whether the measurement can keep up with the change speed of the measured object, and whether it can fully reflect the whole process of displacement change. Vibration measurement is common in occasions with high requirements for measurement speed. Of course, there are many parameters that determine the function of the sensor, including the ability to accept ambient temperature targets, the acceptance of vibration and shock targets, and so on. Why pick the right target? Because the higher the technical parameters, the more messy and difficult the production process, and the higher the price. Therefore, when you formulate measurement requirements, you must not imagine and put forward a super high measurement requirements. I have seen some sensor application units, often require a few microns, or even nanometer level measurement accuracy, the measurement speed is still super high, ask it is really necessary to put forward such a high requirements? Answers are often unnecessary, perhaps demanding and marginal. However, we must remember that there is no such thing as a costless goal increase, and behind every high goal is real money. In addition, when selecting a laser displacement sensor, it is necessary to pay special attention to the fact that the labeling standards of parameters are different from one manufacturer to another. For example, Germany brands generally indicate real parameters, or even saved parameters. For Japanese brands, when labeling, the uniform result will prevail. When looking at the parameter table, take a closer look at the small print below, the ultra-high parameters of Japanese brands often come from the results of repeated uniformity. Optical measurement will produce some burrs, and the measurement results can be greatly smoothed through a uniform method.

3. In the selection of brands, among the displacement sensors of many measurement principles, the laser displacement sensor market is the most disordered, and the brand is the most uneven. There are even merchants who only act as agents of a foreign brand, but claim that they are produced by the original factory, and when there is a problem in the future, because the preliminary technical plan has been finalized, they can only choose hard, and this will often bring greater problems in the future. To identify whether a brand is an original product, in addition to the common original factory certificate (this can also be impersonated), the most direct is to look at its Chinese website, foreign brands will generally use their brand title as the website, if you see that the website of a certain brand is a mixture of Chinese and English, it is unlikely to be a regular manufacturer. In addition, the Chinese website of a regular imported brand must be found on the website of its foreign parent company, and what cannot be found must not be a subsidiary. The selection of the brand is particularly critical, because theoretically speaking, the structure of the laser displacement sensor is not messy, and small domestic factories can also make it, but the accuracy and repeatability are very different from those of big brands. In addition, the service life, temperature drift, etc., will also greatly affect the customer's application effect. I have seen some of the use of manufacturers, in order to hundreds of dollars of price difference, from the imported brand to the domestic brand, the results of the past 3 years will not be bad a sensor, a year broken 4 times, calculated more expensive not counted, but also greatly affected the use of links, the production line stopped once, but not hundreds of dollars of cost savings can be compensated.

Laser displacement sensor selection method – Turck

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