Design of Batching Controller Based on Industrial Control Machine

0 Introduction

The batching control system used to control the batching process of concrete, feed, cement and other products has the characteristics of real-time and multi task control. At present, PLC is often used as the core control device. However, in the networked production management including multiple production lines and enterprises, the real-time data of production site needs to be controlled by computer, Then, the server is uploaded to the enterprise management, so that the management can not grasp the production instant data in time. This paper studies a kind of batching controller, which serves Ethernet. On the basis of industrial control computer, it uses fieldbus technology, real-time operating system platform, communication protocol and other customized software platform. Its essence is an embedded system, which integrates software and hardware technology. It can replace the traditional industrial control computer + PLC in use and control the production process, At the same time, the data of each workstation is transmitted to the server to realize the integration of production control and information decision-making, which is suitable for networked process control system.

1. The working principle of controller

In order to realize network production management in the production process of concrete, feed, cement and other ingredients, the structure layer should be layered, including management, control layer and equipment layer. After adopting this batching controller, the batching control system can realize the management layer (composed of all departments of the enterprise, such as production scheduling, material management, financial management, chief engineer and general manager) through the central switch and the next level control network, so as to monitor the whole control system, extract production data and analyze the report; The control layer (composed of engineers and operators) can realize the programming, data analysis and storage of the whole control system; Equipment layer (production site), including controller, intelligent instrument, 1/0 module and fieldbus, etc., the acquisition and conversion of various signals are completed by intelligent instrument and 1/0 module, and the controller realizes the processing of logic control circuit.

As the core of the whole batching control system, the working principle of the batching controller is: through the analysis and processing of system input and operation instructions, receiving the control command of the system, outputting control signals, controlling the batching on the production site, collecting the information of relevant control objects such as the electromagnetic valve, weighing sensor, hopper and electronic belt scale on the production site, and then feedback to the system, The system completes the control of the monitoring object and uploads the real-time production information to the server.

The controller designed in this paper belongs to the special controller of the batching industry, which has the following technical characteristics: it is the control core of the whole batching control system; In essence, it is a embedded system, which needs to be selected, configured and developed in software; It is a distributed control system based on Ethernet, which can realize real-time and multi task control; It has the characteristics of stable control and high efficiency of special controller.

2. System structure design of the controller

The batching controller is the soft controller developed on the basis of industrial control machine. According to the work requirements, its logic can be defined in real time and can transmit the data on site based on Ethernet network, and realize the integration of production field control and information decision. From the system structure, the batching controller is actually a embedded system, which integrates software and hardware technology. In the design process, in order to realize the special controller specific hardware system and software structure, in addition to the control requirements of specific objects such as solenoid valve and intelligent instrument in the process of batching production, the controller is designed to meet the control requirements of specific objects such as solenoid valve and intelligent instrument, The problem of interconnection and remote control of all devices in the whole control system should be solved, that is, the support capacity of fieldbus, production data analysis and storage function, network function, etc. should be considered, and sufficient resources should be reserved for the subsequent system upgrade, and the characteristics of stable control response and high efficiency of special controller should be reflected.

Because PC platform has rich software support and powerful processor function, the design chooses industrial computer as the hardware platform, then develops custom control half and pusher software platform. During the design process, the compiled files are downloaded to the target controller for debugging and running, and then the controller is put into normal operation after success.

2.1 hardware design of controller

The controller hardware includes industrial computer and master card to meet the requirements of information processing and real-time control. Industrial control computer includes main board, power module, data communication line, etc. the main board is configured with fscesl713vnaintel845gv chip set and Pentium4 processor. The Profibus master card can meet the design requirements.

The hardware selection of the controller is based on the industrial control computer. Although the quality and volume of the industrial control computer are relatively large, it has important advantages: the power supply of the industrial control machine has the ability of multi voltage DC output, and can supply power to other equipment (such as the master station card); The main board is fully compatible with pcv/isa bus standard, which is convenient to add PCI function board; The program can be transplanted easily by connecting the display.

PROFIBUS master card includes master board im181 and main interface board im180. When used, im18o is inserted into im181 and isa slot of manual control computer is installed. The im18o interface module is mainly composed of special integrated circuit apscz chip, soc165 microprocessor, flasheprom and dual port RAM. It has multiple arbitration lines outside. After using im181, its external read-write arbitration line can only be read from the register, and the register should occupy the space of 8byte at the lower end of dual port RAM.

2.2 software design of controller

The functions of controller in the whole system are as follows: it is the core of the batching control system, responsible for the solution of configuration logic, collecting production data through master station card and sending the control information generated after calculation to the production site. The software development process of the controller includes system initialization, communication protocol formulation and information display and storage, including three modules. The tasks of each module are: (1) system initialization module, which is responsible for initialization of hardware equipment, loading application programs, and converting real mode to protection mode（ 2) Communication module, responsible for solving control logic of the system, collecting production data and transmitting data（ 3) Information display storage module, display and store production data.

2.2.1 system initialization module

The basic hardware used in the design is industrial computer, and the controller works in the protection mode. Therefore, the system initialization of the controller mainly completes three tasks: initialization hardware equipment (completed by BIOS on the main board and the program module generated by assembly language mixed compilation), loading application (completed by bootloader module) The real mode is converted to the protection mode (completed by the program module generated by the assembly language mixed compilation). The initialization process of controller system is: (1) BIOS self check of main board, which gives the control right to initialization boot program（ 2) Self check of the boot program, and if any error is found, it will report the error and stop the machine; If there is no error, interrupt is prohibited, and gdtr and IDTR tables are initialized（ 3) Establish 1/0 interface（ 4) Write the program to memory and complete initialization.

2.2.2 communication module

Profibusdp fieldbus technology is applied to the communication of the controller system. The industrial control machine has serial port, and it is RS-232 serial port, and the quantity is limited. During the design process, profibu is added to the main board of industrial control machine. The master card (im180) extends the number of interfaces to the controller.

Profibusdp system is divided into master station and slave station: the master station determines the data communication of bus. When the master station obtains the bus control right (token), it can send information without external request; Slave station is peripheral equipment, typical slave station includes 1/0 device, solenoid valve, driver, sensor and other equipment. They have no bus control right, only confirm the received information or send information to the master station when it sends out a request. In the process of design, the controller designed is connected to profibusdp system as the main station, and various intelligent instruments on the production batching site are used as slave stations. During the process of setting PROFIBUS master card, the upper part of communication is set as event excitation, and the lower part is set as interrupt response, that is, the upper computer sends out the command to the lower computer actively, the lower computer passively receives the instruction and feedback the execution instruction, and forms a dialogue and communication mode between the upper and lower computers. After the Profibus master card and system configuration are completed, the whole profibusdp system is the master-slave structure. The master station has control and bus control over the slave station, and the slave station uses the bus under the control of the master station and works normally.

2.2.3 information display enclosure

In the normal process of the batching controller, it is necessary to strictly coordinate and control each batching scale (or each batch production line), and monitor and adjust the material level and flow accurately in time and accurately. Therefore, in the design process, a nucleus real-time operating system with good real-time performance is selected. Nucleus real-time operating system has not only the function of common operating system, but also the functions of task control, task communication, task synchronization, memory management, programmable, standard input / output device interface, etc.

The controller control scheme is realized by configuration software. The main problems of configuration software are: data acquisition and data exchange with field equipment; Connect the collected data with the related parts of the upper computer graphics interface; Data alarm limits and system alarms; On line monitoring of real-time data; The storage of real-time data and the query of historical data; Whether the application system is stable and reliable. In the process of working, the controller connects a computer with configuration software or embedded integrated touch screen. The control scheme is edited in the configuration software, and the generated program is downloaded to the controller hard disk for operation. MCGS configuration software of Beijing Kunlun TongZhou company was used in the design process.

3.Conclusion

The proportioning controller designed in this paper is a controller designed for the batching process of concrete, feed, cement, etc. it can replace the traditional industrial control machine +plc mode and the traditional lower computer and upper computer mode in the batching control system, reduce the intermediate link, make the hardware simpler and cleaner, optimize the single system of PLC which is usually used as the controller in the current batching industry, and use the network function, The real-time information of production is transferred to the management of the enterprise, which has a good application prospect.

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