ControlNet's Application in Vacuum Control System of Positive and Negative Electron Collider in Beijing

The Beijing Electronic Negative Collider (BEPC) vacuum system is used to maintain the high vacuum of the accelerator beam pipe to ensure that the positive and negative electrons are accelerated and stored therein. Its control system uses process control equipment to control various ion pumps, vacuum gauges, and vacuum valves. In the Beijing Electronic Negative Collider Major Transformation Project (BEPC), EPICS will be used to upgrade the existing control system. In the vacuum control system, Rockwell Automation’s ControlLogix system is used as the vacuum coupling. The lock protection system simultaneously controls the vacuum valve, which communicates with the front-end VME computer via the ControlNet control network.

1ControlNet Control Network A new real-time fieldbus network oriented to the control layer, which simultaneously supports I/O information, real-time interlocking of controllers, and communication message transmission and programming operations on the same network link. As follows: Programming can use the same network and reach the same speed.

Using an advanced producer/consumer network model, information is identified by content. If a node wants to accept a data, it only needs to identify the specific identifier associated with this information. Each packet no longer needs to provide the source address and target. Address information. Because the data is identified by content, the data source only needs to send the data once. Many nodes that need this data can simultaneously consume the same data from the same producer by identifying the identifier on the Internet. This maximizes network bandwidth utilization and supports multi-host, multicast, and peer-to-peer application relationships.

The data link layer Media Access Control Protocol (MAC) employs a special implicit token passing mechanism, and a special time-slicing access algorithm is designed to ensure network update time-neutral (NUT) time Each node on the network is automatically tuned to take advantage of the implicit token passing information. ControlNet's technical specifications stipulate that the configurable NUT time is 0.5~100ms. Each NUT is divided into 3 parts, namely scheduled part, scheduled part and maintenance part (maint-). Nance).

6 coaxial cable, simple installation, strong anti-interference ability, each network segment can be extended 1000m and can use repeater extension. The optical fiber can be used in outdoor, dangerous and high electromagnetic interference environment. When mixed with coaxial cable, it can be extended to 25km. Optional media redundancy, which is especially important in high reliability requirements.

Research students, mainly engaged in research and development of accelerator control technology. , ElectronicPublishingHou, 6) Application-oriented design. The metering method uses an abstract object model to describe the product's communication functions. 2 System Structure Beijing's positive and negative electron collider control system was built in 1987 and was rebuilt in 1994 using a VAX4500 computer and a CAMAC1/O device for storage ring magnet power, high Frequency and vacuum equipment are controlled, and other subsystems are basically controlled by a PC. At present, the industrial and accelerator control systems in the world have been developed using vis() ryControlandDataAcquisition) products, ie configuration software packages, and EPICS is a joint venture between the Los Alamos National Laboratory (LANL) and the Arng National Laboratory (ANL). Developed non-commercial SCADA products that support high-energy physics experiments and commonly used VME and CAMAC front-end devices in the accelerator community, and many high-energy physics laboratories developed accelerator-specific applications on the EPICS platform to achieve software sharing and reduced Application development workload. At present, EPICS has been used by more than 50 high-energy physics experimental facilities and control systems in the world. The Beijing Electronic Negative Collider Control System Improvement Project will also use EPICS to upgrade existing control systems.

EPICS consists of three parts: an operator interface module (OPI) running on the client, an input/output control module (IOC) running on the server, and a channel access module (CA). They work in a network environment in client-server mode. Clients generally run on Unix operating system platforms. Servers generally run on VxWorks operating system platforms. EPICS/I0C is installed on the front end of the server as a server. The core of I0C is a distributed memory database system, which stores real-time data from and to the device. EPICS/CA is network communication management software. It supports TCP/IP protocol and is installed on client computers and front-end machines as servers respectively. Using CA tools, users can directly read and reside in the IOC from the operator console through transparent communication. Real-time data in the database. The EPICS/OPI residing on the client provides I0C database generation tools and human-machine graphical interface development tools and device monitoring tools.

Under the EPICS framework, the vacuum positive and negative electron collimator control system in Beijing is divided into three levels: operator interface layer (OPI), input and output control layer (I0C), and device control layer. OPI is set up in the central control room and can also be used for local control and equipment maintenance. I0C runs on Motorola's PowerPC 750 series CPU board MVME2431 based on VME bus 13-4, which interfaces with vacuum gauge controller, temperature monitoring system, ion pump power controller and vacuum interlock protection system via RS-232 and ControlNet respectively. , VME bus ControJNet interface card is Wo (XdheadImhstries company's SST5136-CN-VMEl5. Vacuum valve is controlled by the vacuum interlock protection system. Vacuum control uses a total of two VME / IOC systems and two Contro for vacuum interlock protection - Logix5555 PLC system: Input module 1756/IB16 of ControlLogixPLC system receives vacuum alarm signal and vacuum valve status signal from vacuum gauge controller, and output module 1756/OB16 outputs switching action signal to vacuum valve.PLC vacuum interlock protection algorithm in PLC It is realized in the 1756/LSM12 processor module in the system.The input and output of the PLC system must also be controlled and monitored by the upper layer. As part of the entire machine interlock protection system, the PLC vacuum interlock protection system also directly protects the central safety interlock. The system outputs interlock protection signals to protect other equipment such as high-frequency systems.

When the ion pump power controller fails (power failure, overload, high voltage short circuit, etc.), vacuum interlock protection should also be caused. Since the selected ion pump power controller can only transmit these fault signals via RS-232 communication, their interlock protection algorithm will be implemented in the control flow of the I0C data record. The generated vacuum protection command sends the PLC vacuum interlock via I0C. Protect the system and close the corresponding vacuum valve. In addition, PLC vacuum interlock protection system will also open/close the corresponding vacuum valve when receiving commands from the console, vacuum temperature monitoring system or signal from the machine interlock protection system.

3 ControINet control network configuration ControJNet control network must determine certain parameters to operate, these parameters include network update time NUT, network need to use sche (diled period of the highest node address SMAX to send information, need to use unscheduled period of time to send information the highest node address UMAX Physical parameters (number of nodes, cable length, and number of repeaters), data size to be exchanged between nodes, and requested data packet interval RPI, etc. Configuration is achieved through the configuration software provided by the product, and the development of the system is programmed. The configuration environment is as follows: the OPI layer SUN workstation runs the Solaris 8 Unix operating system to develop the applications and the man-machine interface of the EPICS IOC; the IOC runs the VxWorks 5. 4 operating system; and another PC for PLC system development installs the Windows 2000. , on which RSLogix 5000 is programmed for ControlLogix PLC programming and its module configuration, RSNe-worx4. 01 is used to configure G)rtroINet network, RSLinx is used to install the communication driver, RSLogix5000 and RSNetworx use this driver card to exchange with ControlLogixPLC Data and some network parameters; 190 Beijing Jingzheng Electronics Collider vacuum air control system! Simulation results of graphing CPublishing step signal simulation Schematic diagram of square wave signal simulation results Traditional BP algorithm identification results so it does not need to directly use state input or training signals, making the network input layer neurons have a larger number of compared with the traditional feedforward network cut back. In this paper, the improved BP algorithm is applied to this model, which greatly improves the real-time and rapidity of the algorithm and is very suitable for real-time systems. The simulation results further demonstrate the feasibility of this algorithm.