MOXA tunnel monitoring solution

With the development of the economy, transportation as the lifeblood of economic development has become the top priority of China's construction. China has a vast territory and complex geographical conditions. Tunnels have become an important part of road construction. Due to the particularity of the tunnel, it is difficult to use in the opening, running, post-disaster rescue, traffic guidance, etc., especially for medium and long distance tunnels. Therefore, the tunnel adjacent system plays an important role in the safe and reliable operation of the tunnel and has become an indispensable part of today's highway tunnel construction projects.

Industry Background <br> Tunnels are an important part of highways and urban roads. According to current international design standards, long tunnels and extra-long tunnels require monitoring systems to ensure safe and smooth traffic within the tunnel. There are various complicated systems in the tunnel, such as lighting system, ventilation system, traffic guidance system, CCTV system, fire alarm system, fire control system, emergency telephone system, and broadcasting system. The connected devices are more complex and can be divided into: detection equipment, control equipment, display equipment, and communication equipment. Detection equipment such as: fire alarm probe, vehicle detector COVI, visibility detector, wind speed and direction, etc.; control equipment such as traffic area controller, lighting area controller, ventilation area controller, etc.; display equipment such as: computer workstation, large screen Monitors, sound and light alarms, etc. Communication equipment such as: switches, hubs, serial signal transmission equipment, optical transceivers, etc.

The whole system is divided into two parts of the regional control and control center. No matter which method is used, the core idea is to combine all the vertical and horizontal systems organically, and finally realize the most humanized automatic control through algorithm analysis. . The core of all this is the zone controller. Each area controller is responsible for collecting information of the on-site detection equipment, which is then transmitted to the local control center, and the control commands of the local control center are sent to the area controller, and then the area controller controls the corresponding equipment. Moreover, in the event that communication between the local control center and the regional controller is interrupted, the regional controller still has the ability to independently control the field devices. Therefore, the requirements for the zone controller are efficient and highly reliable.

The local control center of the control center is generally composed of a field monitoring workstation (control computer), monitoring system software, a main area controller and corresponding auxiliary equipment, which is used for unified monitoring of the entire tunnel monitoring system. The monitoring system software continuously exchanges data with the PLC controller, and displays the current status of all devices in the real-time mode in the color, flashing, numerical value, etc.; and each action of the operator in the operation interface is also performed by the monitoring system software. Related commands and parameters are written to the PLC to implement manual control of the device.

In addition to the high performance of the regional controller itself, the communication network running through the entire system is the key to ensuring that the regional controller becomes the core of control. With the continuous improvement of tunnel construction technology, there are more and more long tunnels and extra-long tunnels, and there are more and more regional controllers in the caves, which means that the nodes of the network are increasing. The communication network not only needs to have a high communication rate to ensure the effective transmission of a large amount of data, but also must have fault tolerance to improve the reliability of communication, that is, self-recovery can occur when a network fails, and the devices constituting the communication network must conform to the industry. Level requirements to accommodate the demanding working environment within the tunnel.

The industrial Ethernet Ethernet communication rate is greatly improved, and the universal application of network switching technology greatly eliminates the uncertainty of Ethernet communication and improves the real-time and QoS of Ethernet communication. At the same time, the industrial automation system is developing in a distributed and intelligent direction. The use of communication becomes the key, and the requirements of users for unified communication protocols and networks are increasingly urgent. The above factors have led to the rapid adoption of Ethernet from the field of office automation to the field of industrial automation.

Industrial Ethernet is a LAN technology that applies Ethernet to industrial control and management. It is technically compatible with ordinary Ethernet. Considering the acrylic working environment and high reliability requirements in industrial field, Industrial Ethernet is common to Ethernet. The network has been improved to meet the requirements of industrial applications.

Moxa EDS Series Introduces MOXA EtherDevice Switch The EDS-508 series is an 8-port Ethernet switch designed specifically for industrial applications. In addition to high-performance Ethernet switching, redundant Ethernet, and a variety of real-time network status displays, The high-reliability quality guarantees that your industrial automation system will operate 24 hours a day.

Ultra-fast Redundant Ring features (Recovery Time < 300 ms)

For industrial automation applications, redundancy is an important condition for increasing system stability. MOXA EtherDeviceTM Redundant Switch EDS-508 is equipped with the network backup protocol Turbo Ring developed by MOXA. Turbo Ring allows you to easily set up the Redundant Ethernet Network, its fast and stable Redundant Ring, which provides an automated system to quickly and automatically establish a Reudndant Ethernet Ring within 300ms after the network is disconnected, and immediately resumes normal connection.

Using IGMP Snooping to Control Network Traffic IGMP (Internet Group Management Protocol) functionality is important for industrial networking applications and can be used with Ethernet field protocols such as Allen-Bradley EtherNet/IP, Siemens Profibus, And Foundation Fieldbus HSE (High Speed â€‹â€‹Ethernet). These industrial Ethernet protocols use the publisher/subscriber communication model to multicast packets to avoid excessive network traffic. IGMP Snooping can sort traffic from multicasts and pass packets to destinations that really need them, thus reducing traffic on the Ethernet network.

VLAN makes network planning easier VLANs are made up of a group of devices, which can be located anywhere in the network, and communicate as if all devices are on the same physical layer. VLANs can be used to cut networks without being bound by physical connections. This is not possible with traditional network design. In addition, because all automation systems contain sensitive devices, these devices need to prevent unauthorized access. Therefore, the establishment of an identity authentication system is very important, and only authorized users can enter and leave the system. If the devices belong to different VLANs, they cannot communicate with each other to provide security and to avoid unauthorized access or traffic. The IEEE 802.1Q standard and the GVRP protocol can exchange parameters between each other so that the VLAN settings in the entire network are consistent.

QoS Improves Qualitative Quality of Service (QoS) capabilities provide traffic prioritization to ensure that important data is delivered consistently and predictably. The EDS-508 Series can detect IEEE 802.1p/1Q layer 2 CoS tag and layer 3 TOS information for consistent grading of the entire network. The QoS capabilities of the EDS-508 family improve the performance and determinism of mission-critical applications in industrial networks.

Redundant Ethernet Ring function (recovery time < 300 ms at full traffic)
Use IGMP Snooping to control network traffic to support IEEE 802.1Q VLAN and GVRP protocols, making network planning easier to support QoSâ€”IEEE 802.1p/1Q and TOS/DiffServ for improved determinism for demanding industrial environments Designing bandwidth traffic management features The expected network status Port Lock allows only certain MAC addresses to be accessed. The port mirroring function provides automatic debugging when the online debugging is detected to the abnormal state. The relay output alarm is automatically obtained through the digital input integrated sensor and the alarm. IP address of the network device patent Line-swap fast recovery
Dual DC can be connected to DC power input operation temperature range from -40 to 75 Â°C (-T wide temperature model)
Rugged IP 30 high-strength housing DIN-Rail or wall-mounted installation mean time-to-failure (MTBF) over 260,000 hours can be set using the Web browser, Telnet/Serial console and Windows utility to check the integrity of the network segment using the ping command 1: Single tunnel monitoring In single tunnel monitoring, it is generally divided into several areas, and the area controller controls the field devices in the area. Other lighting systems and ventilation systems are controlled by the controller of the substation. The main controller is responsible for parsing the commands of the monitoring computer and then giving them to the various regional controllers and ventilation lighting controllers. At the same time, the area control, control, and most The feedback signal of the control is also parsed by the main controller and displayed on the man-machine interface adjacent to the computer.

Case 2: Tunnel Group Monitoring Multiple individual fiber ring networks can be connected for the proximity of a tunnel group. Generally, the entire tunnel group is controlled by a monitoring center, so the endless tunnel must be far away from the monitoring center, so the fiber optic cable of the single mode fiber needs to be used first when the optical cable is connected. As shown in the figure, the single-mode fiber converter can be used to convert the electrical port signal of an ordinary Ethernet switch into a fiber-optic signal, thereby achieving the purpose of long-distance ,, and connecting each fiber ring network to the monitoring center. Centralized control of the monitoring center.
Since the lengths of the tunnels in the tunnel group are different, for many small tunnels with short distances, the number of control points is small, and it is wasteful to have a full set of input and output. Therefore, it is more suitable for the application of distributed PLC control system.

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