Solution

Atekon Technology Co., Ltd.

Typical Solutions for Highway Tunnels

Release date:

2020-03-27

The tunnel monitoring system primarily consists of three major categories: monitoring equipment, alarm devices, and control & guidance systems. Typically, the CCTV system, broadcasting system, and alarm system (including fire detection, alarm buttons, and emergency phones) operate as standalone subsystems. All other equipment, however, is integrated into the monitoring process through regional controllers and their communication networks. Generally speaking, monitoring in each tunnel is structured across three distinct levels: the top level is the local control center, the middle level comprises regional controllers, and the bottom level includes various detection devices (such as vehicle detectors, visibility sensors, CO concentration detectors, wind speed and direction sensors, brightness detectors, and over-height vehicle detectors), along with the associated control and guidance systems.

System Architecture and Configuration

Aoto Technology, as a provider of a full range of automation products, can offer a comprehensive solution for tunnel monitoring systems.

 

方案一：NA400 PLC

 

The PLC and communication network are the core components of a tunnel monitoring system, and the selection of the PLC along with the performance of the monitoring system's communication network play a decisive role in determining the overall effectiveness of the tunnel monitoring system. Choosing the right PLC and communication network based on the specific characteristics of the tunnel and its monitoring requirements is a critical factor in ensuring the system delivers optimal performance.

 

In terms of communication, Nanjing Aoto provides users with a wide range of options. Whether it's the PROFIBUS communication network built on fieldbus technology or the industrial Ethernet network based on Ethernet technology, both can effectively meet the tunnel monitoring system's requirements for communication network performance and reliability.

 

Aoto Technology's NA400 series PLC solution offers users a cost-effective solution thanks to its stable performance, robust communication capabilities, and competitive pricing.

 

Here's an introduction to the industrial Ethernet solution based on Ethernet technology:

 

Industrial Ethernet redundant ring networks are robust regional and unit-level networks based on IEEE 802.3 (Ethernet), technically fully compatible with standard Ethernet. At the same time, considering the harsh working conditions and extremely high reliability requirements of industrial environments, Industrial Ethernet incorporates tailored enhancements over conventional Ethernet to better meet the needs of industrial applications.

 

Technical Features >>>

  • Industrial Ethernet technology is technically compatible with IEEE 802.3 / IEEE 802.3u and utilizes ISO and TCP/IP communication protocols.
  • Redundant 24V DC power supply;
  • Simple cabinet rail installation;
  • Conveniently configured in star, linear, and ring topologies;
  • A high-speed, redundant security network with a maximum network reconfiguration time of 0.3 seconds;
  • Network components can be used in harsh field environments and have passed EMC testing;
  • Powerful network diagnostics and management features, supporting SNMP;
  • Supports web-based network management.

 

As shown in the diagram, the monitoring system’s communication network employs an industrial Ethernet redundant fiber-optic ring network. This redundant ring network utilizes industry-specific redundant ring network switches, ensuring highly reliable network communication. Specifically, even if a fault occurs at any single point on the network, normal communication can be restored within 0.3 seconds—without disrupting time synchronization between devices. For local control, the NA400 series PLC is chosen to manage the input, output, and control of field digital, analog, and serial communication devices (such as large information display boards). The NA400 PLC connects to the fiber optic switch on the fiber-optic ring network via Ethernet. In the main monitoring room, a locally configured NA400 hot-standby redundant PLC is also connected to the industrial Ethernet redundant fiber-optic ring network through the same switch. Operators use a touch screen in the monitoring room for real-time field control and surveillance. Meanwhile, the NA400 PLC serves as the central controller and coordinator for the entire tunnel monitoring system, seamlessly uploading system data to the monitoring sub-center, enabling operators to achieve centralized oversight and management.

 

 

 

Option 2: NA400 PLC + NA300 PLC

Aoto Technology's NA400 Series Hot-Standby Redundant Core Controller + NA300 Series Regional Controller Solution.

PLC Network Structure Topology Diagram:

 
 
 
 
 

 

方案三：NA400 PLC + NA2000 PLC

 

The monitoring system consists of a three-tier network structure: the Central Control Center, the Tunnel Monitoring Center, and the On-site Monitoring Terminals. Nantai Aoto's products primarily handle data acquisition tasks at the Tunnel Monitoring Center and the On-site Monitoring Terminals. Specifically, the Tunnel Monitoring Center is equipped with the NA400 mid-to-large-scale PLC, utilizing a hot-standby redundancy system solution that ensures power, CPU, and network redundancy, thereby guaranteeing the secure and reliable collection of critical data. Meanwhile, the On-site Monitoring Terminals mainly employ our company’s NA2000 series of intelligent controllers. Developed with an integrated, compact, and network-oriented approach, these controllers are tailored for core applications such as IoT-based terminal control units and automated mechanical equipment control units. The NA2000 features an integrated Ethernet interface, multiple RS485 ports, and a wide range of I/O interfaces, supporting bus-type Ethernet cascading. Data exchange between the terminals and the NA400 PLC is facilitated via a fiber-optic ring network.

 

 
 
 

PLC Network Structure Topology Diagram:

 
 
 
 
 

 

方案四：NA300 PLC + NA2000 PLC

PLC Network Structure Topology Diagram:


 

 

 

Traffic Monitoring System Functions

 

Automatic System Event Monitoring

Vehicle-stopping detection, traffic congestion detection, pedestrian detection, vehicle-running-against-the-flow detection, low-speed vehicle detection, abandoned-object detection, vehicles with following distance below the limit detection, fire detection, and casualty detection—and the system can prioritize alerts to prevent multiple alarms for the same event.

 

Automatic recording

When an accident or traffic incident occurs, the system automatically triggers an alarm and simultaneously starts recording the event for at least three minutes (including one minute before the incident and two minutes afterward; the recording duration can also be adjusted according to the specific needs of the situation). The system then transmits and stores these recordings in the central event detection workstation, making it easier for analysis. Additionally, the system offers several recording options: automatic recording upon incident occurrence, continuous (permanent) recording, administrator-initiated recording, multi-camera recording mode, and external-triggered recording.

 

All-weather detection function

Regardless of day, night, rain, snow, or fog—under all kinds of weather conditions—as long as the human eye can detect the movement of vehicles, even on roads without lighting, as long as the vehicles have functioning headlights and taillights, various traffic events and accidents can be detected seamlessly.

 

Traffic Data Detection

Traffic volume, average vehicle speed, occupancy rate, headway, queue length, vehicle type, travel time, and vehicle classification (3 types);

The system runs a self-diagnostic program on the analyzer, automatically detecting the following errors:

Camera position shift, camera signal loss, analyzer error, network communication failure, system resource status;

 

Incident and Accident Detection

The computer is responsible for managing and statistically analyzing event detection along the route, as well as transmitting alarm signals to the entire monitoring system.

The system should feature intuitive, user-friendly settings as well as convenient maintenance and management capabilities.

It should feature differentiated settings for multi-level user operation permissions in the maintenance management environment, enabling multiple users with varying privileges to simultaneously perform system operations and management tasks.

 

Data Output Interface

The standard Ethernet interface allows event and incident alarm data to be accessed by other application systems via the TCP/IP protocol, enabling additional functionalities such as alarm linkage—for instance, direct control of video matrix switchers or integration with comprehensive emergency response management platforms.

 

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