Auto Industry
Case study
Automotive assembly line control system based on the DeviceNet field bus

Summary: DeviceNet Fieldbus The Rockwell Automation introduced, is a low-cost, open, reliable and efficient industrial control network can be widely used in various fields, has become the international standard, European and Chinese National Standards. According to China First Automobile Group's development plan, it designed the automotive assembly line control system based on the Fieldbus DeviceNet, describing the structure of the system and its powerful features. The system comprises a DeviceNet network 12, the plurality of nodes 200, a bus length of 3000m. The overall system technology has reached the international advanced level. Operation and practice, systems and improve business productivity for enterprises to create significant economic benefits.
Keywords: automobile production line DeviceNet PLC control system

I. Introduction
DeviceNet Fieldbus is a provider of world class automation control information solutions and - Rockwell Automation (Rockwell Automation) introduced the best network control technology --NetLinx underlying network. DeviceNet having a low-cost, open, reliable and high efficiency, especially suitable for high-level control of real-time industrial field requirements.

DeviceNet has become the standard IEC62026-3 (2000-07) Voltage switches and international equipment control - device interface, has also been identified as the EN50325 European standard - Controller. In addition, DeviceNet is, in fact, a standard device network for Asia and the Americas. DeviceNet is supported by the public and more manufacturers around the world have been registered in line with several DeviceNet specification thousands of products, the practical application of DeviceNet node device has reached millions. In North America and Japan, DeviceNet occupy the largest market share in similar products in the rest of the world is also showing a strong development momentum.

DeviceNet enter the country, although late, but because of its prominent advantages and highly valued departments and relevant units of China. 2002 October 8, DeviceNet was approved as China national standard GB / T18858.3-2002, and started on April 1, 2003, so as to further promote the DeviceNet fieldbus technology popularization and application in China.

DeviceNet can be widely used in various industries for the automobile industry of China, for example, DeviceNet was applied to the FAW - AUDI A6 Volkswagen Automobile Co., Ltd., BORA A4, JETTA the production lines of welding, assembly line, Zhangjiagang Peony welding factory automobile production lines, assembly lines, automotive coating factory Qingdao Yizhong, coating line bogies Changchun bus factory, Hafei Motor welding factory production line, coating production lines, assembly, and so on. This article describes the DeviceNet FAW - Volkswagen BORA A4 application assembly production line.

Second, the assembly line design goals
FAW - Volkswagen BORA A4 assembly line design is based in China First Automobile Group Corporation planning the development, equipment and control system of the original assembly line technological transformation project, designed to meet JETTA BORA A4 and mixed production line of two models Requirements to achieve production capacity of 90s / vehicle, with an annual output of 150,000. assembly design of advanced technology in the world of modular assembly technology technology and more flexible production line models blended production line, and with efficient, reliable, easy to maintain control system to improve the quality of vehicle assembly .

BORA A4 production line process by memory area, workpiece assembly area, survey area, access area, detection zone, winding zone. mechanized production line system includes a vehicle assembly (process chain, driven by multiple engines), the vehicle body transport line (for release of the chain product), the reserve line (chain product release) , elevators and the like. In that the stopper 22, impeller 10, the switch 6; motor control unit and requiring frequency control, the number of field devices and controlled with a high degree of dispersion: I / O point of about 2600, a length up to 3000 m.

In order to meet the design requirements of the production line and possible cost savings, under the premise of full utilization

the equipment and wiring of the original distribution systems of the most reasonable re-arrangement existing; in transgenic lines are installed between the respective pusher lines avoided transfer line failures; the balance rail using the new system, so that the smooth operation of the production line, reliability, reduce the intensity of work, the car assembly line of the carriage to raise the assembly line, the increase of the assembly line of automobiles for the whole Two stations, an additional robot mounting station.

original production line control system is first designed using a traditional centralized PLC control system and low-precision control control, all digital and analog I / O connection points are PLC cabinet, a large amount of lead, complexity of spinning, high failure rate, site maintenance for a number of disorders, seriously affected production, no longer suited to the production needs of the modern enterprise. Therefore, necessary to design a new high-performance control system, which is the key to the production line to achieve a predetermined design goal.

2.1 control system
After analyzing and comparing a variety of different DeviceNet control field control schemes decided bus control system for the underlying network, as shown in FIG. input devices connected to the push button, DeviceNet network emergency stop switches, proximity sensors, photoelectric switches, limit switches, etc., has an output light device, a control valve, the unit and the like. ControlNet communication system implemented by another between different PLC, to complete the central control room monitoring, control, fault alarm, management information exchange functions.

Figure 1 Fieldbus control system with assemblyNet as the underlying network

Figure 2 PLC-5 / 80C hardware configuration

Figure 2 is a Rockwell Automation system used in the 80C-5 PLC hardware programmable controller (which itself has a remote I / O (RIO) built-in and ControlNet interface). Since the multi-point control system, the long line, so that with six 1771-SDN scanner, connected to a total of 12 Network DeviceNet and the device controlled. DeviceNet network 12 are named 1DN1,1DN2,2DN1,2DN2,3DN1,3DN2,4DN1,4DN2, 5DN1,5DN2,6DN1,6DN2. Wherein, 14 1DN1 controls the entire production line of the inverter; more flexi control 1DN2 all devices on the I / O production line, flexi I / O is connected to the original assembly line can not be connected directly to a device of a DeviceNet network; 2DN1 control the body transport line (discharge volume chain); 2DN2 reserve control line (product release chain); 3DN1 3DN2 control and another reserve (product release chain); 4DN1 6DN2 for the vehicle assembly control (process chain). The assembly process of the vehicle is very complex, consists of 153 composite stations, the process control point in primary function, and other chain of equipment; main equipment chassis marking machine, robot opening roof mount, robot coating, robot assembly, windshield Robot glass coating, control module drive system, powertrain, detection device, etc. . The system has more than 200 nodes.

operating status of all field devices, operating parameters, etc. information transmitted through the DeviceNet network to control room located in the controller fails, and a controller to control a variety of field equipment is implemented via DeviceNet. computer system connected to the monitoring application in the EtherNet RSView32 configuration software, rich text, graphic status of each image display production device, operating parameters, auto pop-up fault alarm screen, point recording of failure, call the relevant control program and electronic control drawings, can also be produced automatically record information, statistics management and alarm information (the point of failure, cause of malfunction, failure time, etc.) to the remote terminal maintenance department, and can be connected to the Ethernet network. The controller controls the start and end of the production line, changes the control parameters, and so on. System via the remote I / O is mounted on the control panel of the HMI man-machine interface, to indicate the operating state of the production equipment, operating parameters, and other control parameters are set. The system has a complete PLC automatic fault diagnosis system and HMI alarm, so that the failure of the consulting device

a is extremely fast, convenient and accurate. automatic closed-loop control system using the current technology to solve the single-chain synchronous control technical problems of the unit, to ensure the normal and safe operation of the production line. The system uses ControlNet's redundant control layer line of port distribution networks, the elevator control system, such as the PLC processor panel assembly system for real-time exchange of control information.

2.2 System Building and Debugging
The field of all real-time transmission signals to the DeviceNet network controller that control signals are transmitted over the DeviceNet network to the field devices, so the DeviceNet network is the foundation for building a control system that is constructed following the steps :

Perform overall planning and reasonable wiring;

Connect the device from the DeviceNet network node to the network;

RSLinx communication software installed and RSNetWorx network configuration tools for DeviceNet or DeviceNet Manager;

To be added to each address of the device distribution node in a DeviceNet network and set the correct communication transmission rate because the communication rate of each segment in a DeviceNet network all nodes must be uniform and not allow the duplicate node address device;

The programming terminal (a computer or dedicated programming device) connected to the network (via a computer communication card or external communication module) and establish communication, ie configured DeviceNet driver under RSLinx: DeviceNet driver (1784- PCD / PCIDS, 1770-KFD, SDNPT driver) (This operation can only be performed in online mode);

DeviceNet configuration device via a network operating parameter (DeviceNet or the ControlNet top-layer network, Ethernet), such as the I / T data trigger device, the I / O device The packet and the operating parameters of the device itself (eg drive startup mode, maximum Frequency and other operating parameters);

The device configuration parameters downloaded to the node device and a DeviceNet Scanner (1791-SDN) and save the configuration file network configuration tool (for offline viewing the same network or network configuration information).

Configuration of hardware and software wiring of the DeviceNet network is very simple, so the installation system cycle is greatly reduced.

Pay attention to the installation and debugging of the DeviceNet network hardware:

Recommended use. Rockwell Automation DeviceNet bus companies, such as set of cables and connectors (which can greatly simplify the installation of hardware, and improve reliability);

b) The power supply of each network segment can only be grounded at one point;

W. in order to network bus terminating resistor must be properly installed (at 120 ohms, Rockwell standard optional terminating resistance with the system and other companies), is not measured when the electrical system network can-H and CAN-L A resistance between the values ​​must be between 50 and 70 Ω.

Secondly, the
Control-based automobile assembly line DeviceNet field bus system, bus length (3000m), the number of nodes (more than 200), and so are the majority of the country, the overall system technology has reached the international advanced level . three-year practical operating system show that the system is powerful, safe, reliable, flexible operation, FAW - Volkswagen creating significant economic benefits, and significantly improving production efficiency, automation and management level, so that the companies of the fierce Leading position in the market competition.

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