Intelligent network communication controller system based on fieldbus technology plays an important role in the design and construction of control system of chemical industry in China. This paper takes the field bus intelligent controller technology as the research object, carries out professional technology research, and provides theoretical support for the wide application of this technology. In the current research and application of control technology in chemical industry, the intelligent network communication controller based on fieldbus technology has been widely used. Therefore, thermostatic element the researchers of control technology take the characteristics of this control technology as the starting point, and combine with the requirements of control technology in chemical industry, carry out practical research on its application. On the one hand, this research is helpful to the effective development of control technology in chemical industry; on the other hand, it provides technical and theoretical support for the application of fieldbus control technology. Therefore, this research has very high technical and theoretical value in the field of technology application. Fieldbus is a kind of bus system for industrial data control. In practical application, its main function is to solve the problem of digital information transmission between intelligent instruments, controllers of various kinds of equipment and equipment executing agencies in industrial field management, as well as related management systems. Therefore, in the application, it is not only an industrial data line system, but also a data network for data communication and transmission at the bottom of the automation field.
Because this network system has the advantages of simplicity, reliability, economy and practicability in the process of construction and industrial control, it has been widely used in the current industrial control management technology. In the design and construction of field control system in chemical industry, the application of Fieldbus controller technology includes the following technical contents. In the design and construction of communication controller, we require low-voltage distribution room in equipment system to set up low-voltage distribution automation system. Its main function is to collect and monitor the operation data of the matching distribution room. Its configuration and technical requirements are as follows: (1) Data acquisition and monitoring data content. The connection between distribution room and distribution automation system is completed by PROFIBUS-DP bus protocol. Its main transmission monitoring data includes the following points: first, the monitoring data of intelligent equipment in distribution room; second, the monitoring data of intelligent motor protector in circuit system; third, the monitoring data of direct feeding circuit; fourth, the running status data of motor in system; fifth, the data of motor protection device; seventh, intelligent electricity. Monitoring data obtained by force measuring instruments. (2) Control mode. The main control modes of the distribution automation system in operation include the following contents: one is to open and close the feeder circuit of the distribution room; the other is to trip the feeder circuit of the distribution room; and the third is to issue various protection settings to the circuit of the distribution room. (3) Network construction structure, the general low-voltage distribution automation system in the construction should use optical fiber broadband network to ensure its operation and control speed. In the actual design and construction of automatic controller system, the problems encountered by technicians are more complex. After the analysis and research of the technical problems in our country, the problems are summarized as follows. (1) In the application of network communication controller system, the number of main engine system and motor control center system in low-voltage distribution room is large, which improves the difficulty of data transmission in control. (2) Because of the lack of standardized content of technical equipment management in our country, the brand and model of intelligent equipment are not uniform in some distribution room construction, so it is difficult to effectively unify its communication interface, connection mode and communication protocol, which affects the equipment connection, as well as the development of data acquisition and management. (3) The internal network construction of some chemical enterprises also preserves the characteristics of non-standardization, so there are often uncoordinated sites in the distribution and technology network, which affects the development of control network communication. (4) The automated information transmission system in the high and low voltage equipment system of chemical enterprises is not uniform. Therefore, how to realize the client/server data forwarding technical requirements required by the controller is also the main technical problem for technical researchers. (5) In the design and construction of controllers, due to the large number of monitoring equipment in automation system and the different types and types of equipment, the problem of inconsistent data acquisition mode and data form is prominent. Therefore, the first technical point in our research on equipment control technology is to unify the control of monitoring data between different devices. (6) In the current network construction of chemical enterprises, the interface and network protocol used by different equipment are often different. For example, RS485 interface and Modbus-RTU communication protocol are commonly used in intelligent power measurement instrument, while OPC protocol is used in automatic control system of distribution room. Therefore, how to connect all kinds of network interfaces with communication protocols in bus connection and achieve the overall completion of control has become the main content of our research. In order to solve the main problems encountered in the design and construction of the controller, the field bus technology characteristics of the technical researchers carried out the research of the system technology practice scheme. The scheme is to use 2000R /TCP communication controller as field intelligent equipment of distribution automation system.
Its main function is to collect and process the monitoring data generated by the field equipment in the control. Because the network communication controller supported by fieldbus technology has a certain number of downlink communication interfaces and upstream network interfaces, it is equivalent to a small data processing computer in use.
Its main role in use includes the following contents. First, the monitoring data information provided by the intelligent monitoring/protection device is collected and processed, which is transmitted to the main station system in time, and then the remote monitoring and management of the chemical production system is realized. Secondly, the system control background computer and all kinds of control commands transmitted by DCS are transmitted to the data processing equipment in the substation of the system through the data signal to realize the remote control of the substation indoor equipment, especially the switch-on and switch-on equipment. Thirdly, through the design of various internal communication interfaces, the problem of poor network connection between low-voltage distribution room and other automation equipment is well realized, and the communication quality and efficiency between control system equipment are improved.
In order to ensure the stability of network communication controller in operation and achieve its management performance, technicians have adopted the following equipment configuration. (1) The host system uses 32-bit industrial control CPU. (2) The control software system is a real-time multi-task Linux embedded operating system. (3) The connection system adopts the following modes: the downlink communication port is the standard Modbus-RTU protocol; the upstream communication network is broadband Ethernet or RS485/232 bus mode. (4) The local monitoring master station and remote dispatching processing are completed by software communication control. (5) In the design of network communication controller, there should be more than two Ethernet ports, multiple communication serial ports and one RS232 equipment maintenance port. In the practical application of network communication controller, we need to set up the network level of control system reasonably according to its network technology characteristics and practical application, so as to ensure the stability and smoothness of network operation. In the design, its main network level includes the following contents. (1) Interval layer of network production equipment.
This network level mainly controls and manages the field equipment in chemical production, such as low-voltage switchgear, intelligent measurement, start-up switch, etc. equipped with communication interface, which are connected and controlled by this network level. Its connection is connected with the downlink port in the network communication controller. (2) Network front layer. The network front layer is mainly the network layer that connects the slave station equipment with the downlink PROFIBUS-DP master station interface of the controller to manage the slave station equipment. Its management content includes: First, data maintenance interface, mainly responsible for the completion of the controller internal data setting and maintenance management. Secondly, the main and standby switching and data exchange interface is mainly responsible for data refresh and exchange management in the system.
It should be noted here that if the control system adopts the dual controller mode, then the two devices should be set as standby mode for each other. In use, one should be set as the main communication station, while the other should be set as the monitoring standby station. Its main and standby switching is accomplished through this interface. (3) Network station monitoring and control layer.
This network level mainly carries on the network monitoring work to the control system, avoids the occurrence of the control accident caused by the control system failure. Its monitoring and control computer has the same configuration as the network front layer, which consists of single computer monitoring and double computer monitoring.
Under the normal working condition of the system, the workstation monitors and collects the daily data of the distribution automation system, displays them in the computer display system, completes the relevant monitoring and control commands, and transmits the corresponding data collected by the monitoring and control system. In the dual-computer monitoring mode, the standby machine is responsible for switching to the monitoring management mode in time under the condition of the host failure and starting the emergency management work. Automatically switch to standby program after host troubleshooting.