The requirements for automatic control systems of aircraft, missiles, spacecraft and other “heavenly” equipment are well known, while the requirements for automatic control systems of tunnel boring equipment are relatively unfamiliar to everyone. Compared with the automatic control of other industries, the automatic control of tunnel boring equipment has the characteristics of high technical difficulty, harsh working environment, short history of PLC application, and the harm caused by system failure may spread to ground buildings. The example shows that any small fault in the automatic control system of the tunnel boring equipment may be magnified into a major accident, which shows how high the requirements of the automatic control system of the tunnel boring equipment are.

Tunneling equipment is a kind of mobile equipment with vibration. It will generate high temperature, high humidity, high dust and high electromagnetic interference when working. Almost all working conditions that are unfavorable to automatic control systems exist in tunneling equipment. When automation components are used in tunnel boring equipment, malfunctions have occurred more or less. Mitsubishi Electric’s CC-Link communication network and Q series PLC have not found any malfunctions in the application of tunnel boring equipment. Tunneling equipment for tunnel construction between Gubei Road Station and Zhongshan Park Station of Metro Line 2. The tunnel boring equipment automatic control system has the following two characteristics:

① PLC has many input and output points, nearly 1000 switch points and more than 100 analog points.

②The communication between PLC stations adopts the communication network. The PLC system is designed at one time and implemented step by step. The main PLC, 1#PLC, 2#PLC, and 3#PLC are the basic PLCs, and the 4#PLC, 5#PLC, and 6#PLC are the extended PLCs. Choose according to project needs.

1. Structure of CC-Link communication network

The structure of the CC-Link communication network is shown in the figure below: the main PLC is the CC-Link network control PLC, 1#PLC, 2#PLC, 3#PLC hang on the CC-Link to form a sub-regional distributed control system for tunnel excavation equipment. The basic control tasks of tunnel boring equipment; 4#PLC, 5#PLC, 6#PLC are the extension of the automatic control system of tunnel boring equipment, and undertake the control tasks of single equipment that can run independently. They are connected to CC-Link as required. Communications network.

1#PLC accepts the operation instructions of the main PLC, accepts the switch signal and analog signal sent by the main PLC, 2#PLC, 3#PLC to the CC-Link communication network, and controls the 2# and 3# trolleys of the tunnel excavation equipment The equipment of the car, upload the switch signal and analog signal of the 2# trolley and the 3# trolley to the CC-Link communication network. A total of DI128 points, DO64 points, AI8 points, using the Q series PLC of Mitsubishi Electric.

2#PLC accepts the operation instructions of the main PLC, accepts the switch signal and analog signal sent by the main PLC, 1#PLC, 3#PLC to the CC-Link communication network, and controls the 4# and 5# trolleys of the tunnel excavation equipment The equipment of the trolley, upload the switch signal and analog signal of the 4# trolley and the 5# trolley to the CC-Link communication network. A total of DI64 points, DO32 points, AI8 points, using the Q series PLC of Mitsubishi Electric.

3#PLC accepts the operation instructions of the main PLC, accepts the switch signal and analog signal sent by the main PLC, 1#PLC, 2#PLC to the CC-Link communication network, controls the tunnel excavation equipment body and the equipment in the assembly area, and sends the The CC-Link communication network uploads the switch signal and analog signal of the device body and the assembly area. A total of DI128 points, DO128 points, AI24 points, AO8 points, using the Q series PLC of Mitsubishi Electric.

4#PLC has two control modes. It can run independently in the local control mode. In the remote control mode, it accepts the operation instructions of the main PLC and uploads the digital signals and analog signals collected by the 4#PLC to the CC-Link communication network. Signal. There are 24 points of DI, 16 points of DO and 16 points of AI, and the FX series PLC of Mitsubishi Electric is used.[page]

5# PLC has DI24 points, DO16 points, AI8 points, adopts FX series PLC of Mitsubishi Electric, and is not used in this section tunnel construction.

6# PLC has DI24 points and DO16 points. It adopts Mitsubishi Electric’s FX series PLC, which is not used in this section tunnel construction.

The main PLC accepts the operation instructions from HMI and instruction components, directly controls the equipment of the 1# trolley of the tunnel excavation equipment, and accepts 1#PLC, 2#PLC, 3#PLC, 4#PLC to send to the switch on the CC-Link communication network The digital signal and analog signal are downloaded to the CC-Link communication network, and the switching signal and analog signal of the 1# trolley are sent to the 1#PLC, 2#PLC, 3#PLC, and 4#PLC. computer to communicate. A total of DI160 points, DO96 points, AI16 points, AO40 points, using the Q series PLC of Mitsubishi Electric.

2. Main technical problems solved in CC-Link application

CC-Link solves two major technical problems when applied, one is anti-high electromagnetic interference, and the other is long-distance communication. Below we describe them separately.

2.1. Solve high electromagnetic interference and improve the reliability of PLC system.

It is relatively easy to solve the unfavorable conditions such as high temperature, high humidity, high dust and vibration that affect the reliability of the PLC system, but it is difficult to solve the impact of high electromagnetic interference on the reliability of the PLC system. It is no exaggeration to think that the level of anti-electromagnetic interference determines the tunnel excavation. The level of equipment PLC application determines the reliability of the PLC system. For electromagnetic interference, Mitsubishi Electric generally recommends that the grounding point of the strong current circuit be separated from the grounding point of the weak current circuit, and the shielding layer of the twisted pair cable is grounded. Separately, the anti-electromagnetic interference method of the shielding layer of the twisted pair cable recommended by Mitsubishi Electric not only cannot resist electromagnetic interference, but also introduces electromagnetic interference, which is determined by the characteristics of tunnel boring equipment.

Most of the tunnel boring equipment is usually distributed in a narrow space with a diameter of 5 to 6 meters and a length of 20 to 30 meters with electrical devices with a power of hundreds of kilowatts. Interfering with the transmission medium of the CC-Link communication network – twisted pair cable, we use three different methods to solve it. The conduction disturbance of the tunnel boring equipment is mainly coupled through the common ground impedance. We use the method of ungrounding the shielding layer to cut off the conduction disturbance; as for the radiation disturbance, we have taken two measures to cut off the disturbance: one is to strengthen the shielding of the radiation source, and use high-power electricity. The device is connected to the main grounding point with a separate ground wire. Second, the separation distance is increased, and the twisted pair cable is as far away from the radiation source as possible; the induction disturbance of the tunnel boring equipment is mainly coupled through the magnetic field, and the high quality twisted pair cable can cut off the induction disturbance. Due to the analysis of the transmission path and the type of disturbance of the electromagnetic interference of the tunnel boring equipment, a method different from that recommended by Mitsubishi Electric was adopted to solve the problem of high electromagnetic interference, ensure the normal communication of CC-Link, and ensure the normal operation of the PLC system. .

2.2. Solve remote communication and improve the usability and maintainability of PLC system.

I remember that when Mitsubishi Electric launched CC-Link, it was used for A series PLCs and QnA series PLCs. For some reason, its in-network communication and remote communication cannot always meet the needs of use. We used to reject the use of CC-Link for a long time, but this situation has come to Mitsubishi 180 changes have taken place in the introduction of the Q series PLC of the motor. We are now preparing to gradually adopt CC-Link in the tunnel boring equipment. The newly designed tunnel boring equipment generally uses CC-Link.

The tunnel boring equipment used for the tunnel construction between Gubei Road Station and Zhongshan Park Station of Metro Line 2 uses Q series PLC for hardware, CC-Link for inter-station communication, and GPPW for software, which realizes remote computer access to any arbitrary network in the CC-Link network. A PLC can perform remote program modification, remote monitoring and remote debugging, which enables us to remotely perform equipment debugging, equipment control and fault diagnosis in different places, which greatly improves the usability and maintainability of the PLC system.

3. The main advantages of using CC-Link in tunnel boring equipment

① CC-Link communication network has strong anti-electromagnetic interference ability and good electromagnetic compatibility, which is suitable for use in tunnel boring equipment with high electromagnetic interference.

② The CC-Link communication network has good scalability and is suitable for the flexible configuration of tunnel boring equipment.

③ The communication speed of CC-Link communication network is fast, which meets the real-time requirements of tunnel boring equipment.

④ CC-Link communication data volume is large, 16 words and 128 bits can be uploaded to the communication network without programming, which basically meets the needs of communication between tunnel boring equipment stations. At the same time, for individual stations with particularly large traffic, the instantaneous transmission function of CC-Link is used to ensure large-capacity data communication.

⑤ The CC-Link communication network is easy to use, and any Q series PLC in the network can be connected to a computer to debug, monitor, and modify the programs of other Q series PLCs in the network.

⑥ CC-Link communication network has strong long-distance communication capability, and can communicate with any Q series PLC in the network on a remote computer without any special communication software (debugging, monitoring, and program modification).