的盲区：超声波物位计在发射超声波脉冲时，不能同时检测反射回波。 Blind zone of ultrasonic level meter : When transmitting ultrasonic pulse, ultrasonic level meter cannot detect reflected echo at the same time. Because the transmitted ultrasonic pulse has a certain time width and the sensor still has aftershock after transmitting the ultrasonic wave, the reflected echo cannot be detected during the period. Therefore, a short distance from the probe surface downward cannot be detected normally. This distance is called the blind zone. If the measured highest level enters the blind zone, the meter will not be able to detect it correctly and errors will occur. If necessary, the level gauge can be installed higher.
的盲区，根据量程的不同，盲区也不同。 The dead zone of the ultrasonic level gauge is different depending on the measuring range. The smaller the range, the smaller the blind zone, and the larger the range, the larger the blind zone. But generally it is between 30cm-50cm. Therefore, the blind spot must be considered when installing the ultrasonic level gauge. In special occasions, the blind zone is required to be small. At this time, a small blind zone ultrasonic level gauge can be considered, and the blind zone is generally only 4-6cm. But its range is very small, only 0.6m. In many areas of liquid level measurement, because of space constraints and installation conditions, ultrasonic level gauges with small blind spots are required. Market demand, ultrasonic level gauge and level gauge supplied by Anhui Secco Environmental Technology will meet your requirements. The working principle of the ultrasonic level gauge / level gauge is based on the transmission and reception of ultrasonic waves. The transmission speed of ultrasonic waves in the air is constant. The ultrasonic waves are emitted, and then the waves reflected from the liquid surface or the object surface are received, and the timing is controlled from the start of transmission to the end of receiving the echo. The timing of the transmission of ultrasonic waves in the air is determined. Distance L = speed (S) * time (T), because it is a round trip, the actual distance is half the distance L. The depth of the tank or the height of the tank is constant. The actual liquid level is the depth of the tank minus the distance measured by the ultrasonic wave, which is the height of the liquid level or the material level. As a result, ultrasonic or liquid level measurement is achieved. Ultrasonic level gauges play an increasingly important role in daily production. It is increasingly used in various industries. Now let ’s take a look at the characteristics, working principles and technical parameters of the ultrasonic level gauge. The working principle of the ultrasonic level gauge is that the ultrasonic transducer (probe) sends out high-frequency pulse sound waves to meet the surface of the measured level (material). The reflection return echo is converted into an electrical signal by the transducer. The propagation time of the sound wave is proportional to the distance from the sound wave to the surface of the object. The relationship between the sound wave transmission distance S and the sound speed C and the sound transmission time T can be expressed by the formula: S = C × T / 2. Because the mechanical inertia during the transmission of the sound wave pulse takes up the transmission time, the sound wave can not be received in a small area near the ultrasonic transducer. This area is called a blind zone. The size of the blind zone is related to the ultrasonic range.
的特性 Characteristics of ultrasonic level gauge
1. Select a professional ultrasonic small-angle probe, with high transmission power, high sensitivity, long life, and long measurement distance; 2. Set upper and lower limits of any point, inverse value setting, (can be set between any two points in the range of measurement The distance corresponds to 4-20MA or 0-5V, and the sensor can be easily installed and debugged to meet various signal connection requirements). Distance accuracy online calibration can be used for water, alcohol, sugar, beverage and other liquid level control. 3. The output mode has 4--20MA or 0-5V output, and 0-10V output. Digital signal: RS232 (three wires) / RS485 (optional one, agreed upon ordering) The secondary indicator is an intelligent digital display instrument with multiple functions, of which the upper and lower limit setting function can realize the liquid level and material level. Automatic control and alarm. 4. The distance or depth data is directly displayed by the LED digital tube, which is convenient for on-site measurement and has temperature display. 5. Fully enclosed design, can be used in the field, and the liquid can be directly measured. 6.High cost performance and low price
Third, the technical parameters of the ultrasonic level meter: 1, 12 or 24 volts DC power supply. 2, using a fully sealed small angle waterproof ultrasonic sensor design, suitable for harsh environments. 3, the sound beam angle is less than 10 degrees, suitable for small space detection. 4. Range 0.30-3, 5, 8, 9, 10, 15 meters (liquid level, large range can be customized), repeat accuracy: 0.5%, resolution: 2MM with high-precision digital temperature compensation circuit. 5. High-brightness LED digital display, the output signal is 0-5V or 4-20mA industrial standard signal, (0-10V, RS232 or RS485), can realize long-distance transmission, with the general industrial meter can achieve the water level (level) Automatic control. 6, with the inverted distance conversion function, you can achieve the upper and lower limit points arbitrarily set (for example, the depth of the pool is 5M, the sensor is 4.2M from the water surface at this time, the actual water level of the pool can be displayed by setting 0.8M or 4.2M). 7, the ultrasonic transmitter can be set at any point within 0.35-12 meters (optional).