[Definition of visibility]: Atmospheric visibility is defined as the maximum horizontal distance on the ground at which a person with normal vision can still see the outline of the target clearly under the weather conditions at that time.
[Function introduction]: The transmitting end of the atmospheric visibility meter emits infrared light through an infrared LED light source. The infrared light source passes through a certain volume of air, and is scattered by gas molecules, aerosol particles, fog droplets, etc. in the air. The receiving end of the visibility meter determines the visible distance by receiving the intensity of the scattered light from the infrared light source. At the same time, the instrument can continuously measure and output the visibility.
[Detection principle]: 35° forward scattering principle, more accurate measurement.
[Overall appearance]: The overall embracing integrated design makes the layout of the internal cables more reasonable.
[Measuring element]: Optical component lens, infrared LED light source.
[Hardware protection design]:
①. The optical component lens is facing down and has a protective cover to effectively prevent precipitation, droplets or dust from entering the lens and reduce the pollution of the probe surface. This design provides accurate measurement results and reduces the need for maintenance.
②. The protective cover of the probe is made of aluminum alloy with a corrosion-resistant glass fiber coating on the surface.
③. The overvoltage and electromagnetic protection devices of the visibility meter can ensure the long-term safe operation of the sensor.
④. Infrared LED light source, increased filter design, anti-light source interference.
⑤. Low power consumption, internal circuit anti-interference design.
⑥. The DC power supply circuit of the instrument has a dual design of anti-reverse connection and self-recovery insurance.
[Equipment List]: 1 atmospheric visibility measuring instrument + 2 clamps.
[Installation Precautions]:
①. Install the visibility sensor about 2 meters from the ground.
②. Ensure that there are no other objects under the visibility to interfere with the test.
③. The ideal installation site should be at least 100 meters away from large buildings or other facilities that generate heat and hinder rainfall, and also avoid the influence of tree shade.
④. The site should be free of obstacles, reflective surfaces and obvious pollution sources that interfere with optical measurements.
⑤. Choose a suitable location to install the device. The device provides a mounting clamp. Use the clamp to install the device on a 75mm pole. To avoid interference from light sources, the transmitter must be on the south side.
[Power supply mode]: 10-30vdc wide voltage power supply.
[Measurement range]: Default 0-10000m. Optional 0-500000m or 0-800000m.
[Measurement error]: ≤1KM ±2%; ±10% >1KM.
[Resolution]: 1m
[Update interval]: 20s
[Mean time between failures]: (MTBF) greater than 18,000 hours
[Working environment temperature]: -40~60℃
[Working relative humidity]: not more than 95% (30℃)
[Weight]: less than 10kg
[Power consumption]: 0.5w
[Infrared light wavelength]: 870nm
[Signal output method]: RS485, standard modbus-rtu protocol
[Types of measurable visibility data]:
①, real-time visibility value
②, 10min average visibility
③, 1min average visibility
[Optical lens cleanliness level]: The cleanliness of the lens of the infrared light transmitting end and the receiving end can be read in real time, the cleanliness level is 1-5, 5 represents the highest cleanliness, and when the cleanliness is less than 3, the optical lens needs to be cleaned on site.
【Visibility knowledge】:
1. Visibility 20-30 km, excellent visibility, clear
vision 2. Visibility 15-25 km, good visibility, relatively clear vision
3. Visibility 10-20 km, average visibility
4. Visibility 5-15 km, poor visibility, unclear
vision 5. Visibility 1-10 km, light fog, poor visibility, unclear vision
6. Visibility 0.3-1 km, heavy fog, very poor visibility
7. Visibility less than 0.3 km, heavy fog, very poor visibility
8. Visibility less than 0.1 km, dense fog, very poor visibility