Essential Tunnel Monitoring Equipment for Visibility and Brightness Detection

In tunnel operation and management, safety is of paramount importance. Visibility and the brightness conditions inside and outside the tunnel directly affect drivers' visual experience and traffic safety. Therefore, a series of professional detection instruments are applied in tunnels. Below, we introduce three essential tunnel equipment.

I. Tunnel Visibility Detector

FT-SDN1 Visibility Detector

Designed for real-time monitoring of tunnel visibility, the FT-SDN1 operates based on the transmission principle. The transmitter/receiver and reflector are installed oppositely, fixed by brackets and precisely aligned. The optical components emit a high-focus beam to form a detection beam. With an installation distance of 3 meters, the actual detection optical path is 6 meters due to the round-trip dual light path. The beam attenuates due to dust and other substances, and the receiver processes the attenuated signal into a measured value. It should be mounted on the tunnel top or sidewall.

This detector can measure visibility (VI) and carbon monoxide (CO) simultaneously or separately. It features high visibility measurement resolution, unaffected by other stray light sources. Engineered for harsh tunnel environments, it avoids measurement failures caused by environmental factors or vibrations from passing vehicles. With low installation, startup, and maintenance costs, it comes with built-in status display, fault alarm, and data storage functions for easy debugging and maintenance. It offers multiple output methods for convenient data collection. The internal compensation function automatically adjusts gain when the optical lens is contaminated, extending the maintenance cycle. By monitoring visibility in real time, it promptly detects low visibility conditions and warns of emergencies like tunnel fires or smoke by monitoring visibility and air quality.

II. Luminance Detector Outside Tunnel

FT-DW1 External Tunnel Brightness Detector

The FT-DW1 is designed to accurately measure the ambient brightness outside the tunnel entrance. Equipped with optical sensors and intelligent algorithms, it senses external brightness changes with high precision, responds rapidly to brightness fluctuations, and operates stably in complex environments such as 强光 (strong light), weak light, rain, and fog, providing data for tunnel lighting control.

Meeting tunnel lighting control requirements, the controller with preset control modes automatically switches lighting on/off according to the light source measurements provided by the detector. It should be installed approximately 4 meters above the road surface and 120-200 meters from the tunnel entrance. Featuring high reliability and low maintenance, it uses the latest microprocessor technology for digital operation.

III. Tunnel Brightness Monitor

FT-DN1 Internal Tunnel Illuminance Detector

The FT-DN1 monitors illuminance inside the tunnel with fast response speed, detecting changes in tunnel illuminance and transmitting real-time illuminance data to the control system as a basis for lighting adjustment.

This detector works with a controller preset with multiple control modes. The controller automatically switches lighting on/off based on the light source measurements from the detector and preset parameters, adapting to illuminance changes caused by different daytime periods, weather, traffic flow, and other factors. With a sturdy and durable housing, excellent sealing performance, and anti-interference design, it operates in dusty, humid, and vibrating tunnel environments. It is typically installed on the wall of specified areas inside the tunnel, about 4 meters in height and more than 10 meters from the tunnel entrance.