This paper introduces the centralized control system for surface coal conveying at the North Open-pit Mine of China Power Huomei Group, based on the new Beckhoff CX1000 controller from Germany. The control system uses the CX1000 controller as the control unit and achieves full system monitoring, production operation, and management through a real-time Ethernet network. 1 Introduction The centralized control system for surface coal conveying at the North Mine of China Power Huomei Group is the centralized control component of the surface coal conveying system for the under-construction Huolinhe thermal power plant. It is responsible for conveying coal for the thermal power plant, connecting the open-pit coal yard of the North Mine of Huolinhe with the thermal power plant. The coal conveying distance is approximately 5 kilometers. This system fully summarizes the control experience of domestic counterparts and absorbs current advanced control concepts from abroad, actively applying new technologies to achieve the current advanced level of the system. 2 Process Overview The coal conveying system is designed with four conveyor belts (see Appendix 1 for details), with an hourly production capacity of 1200 tons. The centralized control system's basic control tasks include real-time monitoring and control of conveyor belts 101 (primary crusher), 102 (connecting belt conveyor), 104 (secondary crusher), 201 (transfer belt conveyor, 4500 meters), 301 (upper silo belt conveyor, 455 meters), and 401 (distribution belt conveyor, 105 meters) in the coal conveying system. Through a host computer installed in the central control room, each belt conveyor and crusher is centrally controlled. Simultaneously, the system displays the real-time operating status parameters of the belt conveyors and crushers, as well as the parameters of level gauges and belt scales, and provides protection for the controlled belt conveyors. [IMG=Figure 1 Overall Flowchart of Coal Conveying Production Centralized Control System]/uploadpic/THESIS/2007/11/2007111314212046935M.jpg[/IMG] Figure 1 Overall Flowchart of Coal Conveying Production Centralized Control System 3 Control System Structure and Functions In this project, both the master station and slave station control units of the system adopt the BECKHOFF CXl000 controller from Germany. The host computer adopts the BECKHOFF C5102 industrial IPC from Germany. BECKHOFF is a world-renowned automation company that continuously advocates new automation technologies. It has added many high-quality new products to automation applications. The automation system it constitutes has outstanding performance and functional advantages: (1) A complete range of products, from industrial IPCs and bus terminals to servo drives. (2) Wide range of supported protocols: LightBus, Profibus, Interbus, Canopen, DeviceNet, ControlNet, SERCOS, Ethernet, EtherCAT, Modbus, Fipio, AS and common interfaces RS232/RS485, etc. Therefore, it can be widely connected to standard automation products from other manufacturers, such as AB, MODICON, SIEMENS, etc. (3) The unified software platform TWINCAT enables the configuration and programming of the entire Beckhoff product series. (4) The unique power measurement module KL3403 can measure the online voltage, current, active power, apparent power and power factor of the power system. (5) The German Beckhoff CXl000 controller uses a Pentium MMX processor with a clock frequency of up to 266MHz. It can run four PLC control tasks simultaneously, providing a stable and reliable control program running platform for the system. According to the coal conveying production system process, the entire system is set up with one master station and two slave station systems. The master station is located in the central control room, in the middle of the entire system. Slave station #1 is located between crushers 101 (primary crusher) and 104 (secondary crusher), and slave station #2 is located at the drive station of conveyor belt 301 (upper silo). The master station uses a Beckhoff CX1000 controller as the main controller. The main controller exchanges information between the master station and the field slave stations via fiber optic communication, and the communication link between the master station and the host computer is established via Category 5e shielded twisted-pair cable. The specific functions include: (1) Information exchange between the master station and the No. 1 slave station controller to realize the acquisition and control of the No. 1 slave station field equipment (2) Information exchange between the master station and the No. 2 slave station controller to realize the acquisition and control of the No. 2 slave station field equipment (3) Information exchange between the master station controller and the host computer to realize the communication connection between the host computer and each slave station, and realize the interaction between the human-machine interface and the field signal (4) Comprehensive control tasks in the main control room (through the input module and output module configured by itself) In the No. 1 slave station, the German Beckhoff CXl000 programmable controller is used as the master controller, and the information exchange between the system master station and the No. 1 slave station is completed through fiber optic communication. At the same time, the local equipment is acquired and controlled. The specific control functions of the No. 1 slave station are as follows: (1) Through the serial communication module KL6021, the communication connection with the tape comprehensive protection instrument ZB02 is made according to the MOD BUSRTU protocol to realize the 102 (connecting tape) protection function (pull rope switch, deviation switch, blockage). (2) 102 (connecting conveyor belt) is centrally controlled by the host computer, including the acquisition of centralized signals, local signals, running signals, emergency stop signals, etc., and the output of centralized control, local control, running commands and warning signals. (3) 101 (primary crusher) is centrally controlled by the host computer, including the acquisition of centralized signals, local signals, running signals, emergency stop signals, etc., and the output of running commands and warning signals. (4) 104 (secondary crusher) is centrally controlled by the host computer, including the acquisition of centralized signals, local signals, running signals, emergency stop signals, etc., and the output of centralized control, local control, running commands and warning signals. (5) By configuring the KL3403 power measurement module, the voltage, current, active power, cumulative energy and power factor of the substation incoming power supply at 102 (connecting conveyor belt), 101 (primary crusher), 104 (secondary crusher) and 102 (connecting conveyor belt) can be detected and monitored online. (6) 102 (connecting conveyor belt), 101 (primary crusher), 104 (secondary crusher), comprehensive control tasks and interlocking control of the iron remover. In the No. 2 slave station, the German Beckhoff CXl000 programmable controller is used as the main controller, and the information exchange between the system master station and the No. 2 slave station is completed through fiber optic communication. At the same time, the local process equipment is collected and controlled. The specific control functions of the #2 slave station are as follows: (1) Through the serial communication module KL6027, it communicates with the tape protection device ZB02 according to the MODBUS RTU protocol to realize the 201 (transfer tape) protection function (pull rope switch, deviation switch, slippage, blockage, tear) (2) Through the serial communication module KL6021, it communicates with the tape protection device ZB02 according to the MODBUS RTU protocol to realize the 301 (upper warehouse tape) protection function (pull rope switch, deviation switch, slippage, blockage, tear) [IMG=Figure 2 CXl000 embedded PC as slave station master controller on site]/uploadpic/THESIS/2007/11/2007111314274754095E.jpg[/IMG] Figure 2 CXl000 embedded PC as slave station master controller on site (3) 201 (Transfer Conveyor Belt) is controlled by a host computer, including the collection of centralized signals, local signals, No. 1 motor running signals, No. 2 motor running signals, No. 3 motor running signals, emergency stop signals, incoming circuit breaker down-operation signals, fault signals and ready signals, etc., and the output of running commands and warning signals. (4) 301 (Upper Warehouse Conveyor Belt) is controlled by a host computer, including the collection of centralized signals, local signals, running signals, emergency stop signals, incoming circuit breaker working signals, fault signals, release, closing and ready signals, etc., and the output of running commands and warning signals. (5) 401 (Distribution Conveyor Belt) is controlled by a host computer, including the collection of centralized signals, local signals, forward running signals, reverse running signals, emergency stop signals, etc., and the output of forward running commands, reverse running commands and warning signals. (6) By configuring the KL3403 power measurement module, the voltage, current, active power, cumulative energy and power factor of the three motors of 201 (transfer belt), one motor of 301 (upper silo belt), one electric roller of 401 (distribution belt), and the power supply of 201, 301 and 401 are detected and monitored online. (7) By configuring the KL3022 analog measurement module, the detection and online monitoring of one belt scale signal (4-20mA) and six level gauge signals (4-20mA) are realized. (8) The integrated control tasks and interlocking control of 201 (transfer belt), 301 (upper silo belt) and 401 (distribution belt) are realized. (9) The Rockwell DODGECST (soft starter) data transmission and display of 201 (transfer belt machine) are realized. Two industrial control computers (1PC), one color inkjet printer and a control console are configured in the central control room. Two industrial PCs are configured with redundant WinCC HMI applications. The industrial PCs are two Beckhoff C51021PCs (configured with P4 2.4G, 40G hard drive, DDR 256M memory, and 17' LCD monitor), connected to an industrial Ethernet switch via Cat5e shielded twisted-pair cables to achieve high-speed (10/100M) and reliable information exchange between the system master station and the host computer. Specific functions include: (1) Display of the status parameters of the total process equipment on site and the status parameters of each independent equipment (2) Control status display and centralized control of 102 (connecting belt), 201 (transfer belt), 301 (upper belt), 401 (distribution belt), pull rope switch, deviation switch, tearing, slippage, blockage online real-time status display (3) Control status display and centralized control of 101 (primary crusher), 104 (secondary crusher), magnet (4) Online real-time status display of a belt scale and level gauge (5) Detection and online monitoring of the operating voltage, current, active power, cumulative energy and power factor of motors 101 (primary crusher), 104 (secondary crusher), 201 (connecting belt), 301 (upper belt), 401 (distribution belt) (6) Historical data curve display, print (7) Data report display, print (8) Alarm information display (9) Help information display In this project, in order to achieve reliable and high-speed (10/100M) information exchange, an industrial Ethernet switch is used between the host computer and the CXl000 controller. Due to the long distance between the sub-control stations on site, the distance between the main control station and the 1# slave station is 3100 meters, and the distance between the main control station and the 2# slave station is 2450 meters. Moreover, there are actually multiple 6KV high-voltage motors installed on site. In order to completely and effectively prevent the impact of electromagnetic interference on the system, the on-site control and information exchange are realized through single-mode fiber optic Ethernet. The 1# slave station CXl000 controller, the 2# slave station CXl000 controller and the main station CXl000 controller are connected by RealTime Ethernet based on single-mode fiber optic Ethernet. Information exchange between controllers is carried out by publishing exchange variable status values ​​to designated devices or global devices through the Publisher defined by each CXl000 controller, and the Subscriber receives the exchange variable status values. 4. Conclusion The centralized control system for surface coal conveying at the Beikuang Coal Mine of China Power Coal Group has been officially put into operation, and all functions of the control system have met the design requirements. The introduction of new technologies into the control system not only provides reliable system operation but also provides a good platform for enterprise production and management. (Proceedings of the 2nd Servo and Motion Control Forum; Proceedings of the 3rd Servo and Motion Control Forum)