Principles and Applications in Modern Detection
Lasers are widely used in the field of detection, with very rich technical content, and their impact on social production and life is also very significant. Laser ranging is one of the earliest uses of lasers. This is because the laser has many advantages such as strong directivity, high brightness, and good monochromaticity. The basic principle of using the laser transmission time to measure the distance is to determine the target distance by measuring the time required for the laser to travel back and forth to the target.
Now, in the automatic detection and control methods, in addition to ultrasonic sensors and ordinary photoelectric sensors, a new method that can handle long-distance measurement and inspection is added-a laser distance sensor at the time of transmission. It provides the flexibility of use for various occasions, these occasions can include the following:
① Equipment positioning.
②Measure the material level of the material package.
③Measure the distance and height of the object on the conveyor belt.
④Measure the diameter of logs.
⑤Maintain the overhead crane from bumps.
⑥Occasion for error-free inspection.
Pulse Method Measurement and Its Accuracy
Laser distance meters generally adopt two methods to measure distance: pulse method and phase method. The process of pulse distance measurement is as follows: the laser light emitted by the laser distance meter is reflected by the measuring object and then absorbed by the laser distance meter, and the laser distance meter records the time of the laser back and forth together. Half of the product of the speed of light and the time of return is the distance between the laser distance meter and the object being measured. The accuracy of the pulse method to measure the distance is generally about +/- 1 meter. In addition, the measurement blind zone of this type of distance meter is generally about 15 meters.
Four introductions to the use of laser distance meters
(1) Set up the instrument First set up the theodolite on the measuring station, after centering and leveling, install the laser distance meter host on the theodolite bracket, lock it with the connector fixing screw, insert the battery into the bottom of the host, and fasten it.
(2) Preparing for distance measurement Press the power switch key "PWR" to turn on, the host will self-check and display the originally set temperature, air pressure and prism constant values. After self-checking, it will display "good". If you modify the original setting value, you can press the "TPC" key and then enter the temperature, air pressure or prism constant (usually enter the "ENT" key and number keys one by one). Under normal conditions, as long as the same type of mirror is used, the prism constant will not change, but the temperature and air pressure may be different for each observation and need to be reset.
(3) Observe the vertical angle and the temperature is soft and well-pressed. Sight the center of the target plate with the theodolite cross-thread to measure the vertical angle α. At the same time, observe and record the readings on the temperature and pressure gauge. Observe the vertical angle, the temperature and the soft pressure, the goal is to correct the skew, temperature and pressure of the slant distance measured by the distance meter to get the precise degree of distance.
(4) Distance measurement Adjust the hand wheel (or theodolite degree micro-motion screw) and the main machine's pitch micro-motion screw to adjust the sight axis degree of the main machine to make the distance meter telescope accurately aim at the center of the prism. In the "good" state, precise aiming can also be judged according to the movement of the buzzer. The stronger the signal, the greater the movement. The distance meter is moved up and down, left and right, to maximize the movement of the buzzer, and precise aiming is completed. "*". Applications of laser distance meters: Laser distance meters are now commonly used in the following fields: electricity, water conservancy, communications, environment, construction, geology, police, fire fighting, blasting, sailing, railways, anti-terrorism/military, agriculture , Forestry, real estate, leisure/outdoor sports, etc.