Surveillance Systems – Design and Structure of Local and Remote Surveillance Systems

Design scheme and structure of on-site monitoring
  1. Design of monitoring

The lower computer mainly includes local controller, inverter, combiner box, environment acquisition instrument and other equipment. The local controller collects the field data in real time, and also receives the command from the PC monitoring software in the upper computer to the local controller to realize the local control of the inverter, such as controlling the start and stop of the inverter, setting various parameters of the inverter, etc. the field monitoring adopts the embedded MCGS configuration software of tpc7062ks model, which is the “brain” of the lower computer, including the inverter, combiner box Through the collection and processing of these on-site data, the central equipment for the collection and control of equipment such as environment acquisition instrument is displayed in the form of dynamic display, alarm processing and process control, which can enable the on-site personnel to grasp the overall information of the equipment conveniently, clearly, accurately and timely.

1.1 MCGS configuration software

MCGS is a powerful and practical industrial control configuration software, which can be combined with other relevant hardware equipment. Through the collection and processing of field data, MCGS provides users with solutions to practical engineering problems in many ways, such as animation display, alarm processing, process control and report output. It has a simple and flexible visual operation interface, strong real-time performance and good parallel processing performance. The system adopts the embedded version of MCGS configuration software. In the process of interface design, it mainly calls the graphic control, data report, alarm window and other modules in MCGS, and compiles relevant command languages according to the needs of the system. The monitoring system uses multi-level menu to switch the interface and operating system.

  1. Design of local and remote monitoring scheme
WiFi remote control camera
WiFi remote control camera

2.1. Monitoring solution

In the traditional monitoring solution, the whole system is divided into three levels: man-machine interface layer, database layer and data acquisition and processing layer. The man-machine interface layer is mainly man-machine interaction to complete the basic functions of relevant data display, curve generation, report printing, alarm prompt, constant value setting, database history query and so on. The data acquisition and processing layer is mainly responsible for the data acquisition, data message analysis and processing of the power station, Data storage, etc. the human-computer interface and data acquisition layer can adopt different development environments. Both layers are independent application programs. The database layer is the bridge for data interaction between the human-computer interface layer and the data acquisition and processing layer. The human-computer interface layer can store and modify the data of the database, and the underlying data acquisition and processing layer can also store and modify the data of the database. In practice, There are some problems in this solution, such as certain delay in alarm, difficult system maintenance, complex system configuration during multi platform development, and poor flexibility of remote dispatching. In the two parts of local monitoring and remote monitoring designed in this project, the traditional solution is not adopted, but a completely based solution is adopted Net platform can solve the shortcomings of traditional solutions.

Based on the three-tier structure model design, the top layer is the application layer, the middle layer is the business layer, and the bottom layer is the data layer. Compared with the previous scheme, the man-machine interface program and background data acquisition program can be combined into one program, but they are not simply combined, but divided into multiple threaded function modules. Each module has certain independence for system development and maintenance. The web service (including data remote publishing module) and web browser module in are a three-tier B / S structure based on Web technology, It is mainly used for the remote dispatching center to access the power station. The traditional scheme is that the background program collects the data and stores it in the database, and then the foreground interface reads the data from the database and displays it. When there is a control command, it should interact with the background program through the database, during which there is a read

Take the time delay of the command. The scheme in this project can be displayed directly after the data acquisition thread collects the real-time data, and stored in the database to facilitate the next display: when there is a control command, it can directly organize the message to be sent to the bus. In practical application, the delay generally includes interaction delay, transmission delay and action delay of instrument mechanism. The traditional scheme generally has a delay of about 2 ~ 5S. If this scheme is adopted, the delay time can be shortened by 1 ~ 3S

In this way, the field equipment is equipped with RS485 communication interface and adopts Modbus communication protocol. The collected data is transmitted to the communication management machine through RS485 bus. The communication management computer analyzes the transmitted Modbus protocol, organizes the message according to the TCP / IP protocol, and then transmits it to the upper computer in the monitoring room through the optical transceiver. The function of local monitoring is completed by local monitoring computer and web server. They realize real-time monitoring and real-time storage through multithreading technology. Special monitoring software is installed on the monitoring computer to store and analyze the collected data, quickly reflect the operation of field equipment through various styles of graphics and charts, generate reports from the required data, and print and export them for more professional calculation and analysis. The operator inputs the corresponding control information through the software to change the operation state of the equipment to realize control. There is also a special computer in the local monitoring room as the web server of the system to publish the operation of field equipment to the Internet to realize remote monitoring.

  1. 本地和远程监控软件的结构设计

3.1 hierarchical design of monitoring software

In this part, both local and remote monitoring software are developed through Microsoft Visual Studio application platform and C programming technology. Visual studio is a development environment launched by Microsoft. It can be used to create windows applications and network applications under Windows platform, as well as network services, intelligent device applications and office plug-ins. It is the most popular application development environment on Windows platform at present. In the design of monitoring software, three-tier structure is adopted, which are: presentation layer, business logic layer and data service layer.

Presentation layer: it is displayed in Web mode in dispatching center and WinForm mode on local monitoring computer It is used to respond to the input request of the user, and display the monitored data to the user in various image representations such as graphics and tables. The user can make decisions on various data conveniently and quickly.

Business layer: it mainly completes three functions. The main thread module is responsible for the coordinated operation and data interaction of the whole system; The data acquisition thread module is responsible for communicating with the inverter, combiner box and other field equipment, analyzing the messages sent by the field equipment, and organizing the data sent to the field equipment into relevant messages for distribution; The control command thread module is responsible for the message organization and command distribution of user operation commands such as maintenance personnel, which are used for remote control operation and fault handling.

Data layer: it is responsible for interacting with the database, obtaining the final data by adding, deleting, checking and modifying the data monitored in real time in the database, and feeding back the results to the business logic layer to provide the presentation layer with the data source of historical data and alarm data, as well as the records of user settings and system configuration status.

3.2 B / s and C / s system structure

At present, there are two modes for industrial monitoring: C / server mode and B / server mode

C / S mode, i.e. client / Server Mode: it is a distributed computing structure composed of one or more clients and one or more servers (database server, file server, network server, etc.). In the traditional two-tier structure system, the client software is generally composed of presentation layer program, application program and corresponding database connection program, and the server software is generally a kind of database system. The application program is responsible for processing the application logic, then converting the request into SQL according to the application logic, sending the language to the database server, and transmitting the results returned by the database server to the client-side application program for display. This mode is more suitable for running in the LAN environment with small scale, few users, single database and security. The C / S structure makes the functions of the client and server more specific. When the environment and application conditions change frequently, it only needs to implement corresponding changes to the client and server, so it has good flexibility, scalability and portability.

B / S mode, i.e. browser / Server Mode: it is a network structure mode developed from the traditional two-tier C / S mode. With the support of TCP / IP protocol based on the Internet and HTTP as the transmission protocol, the client can access the web server and the back database connected with it through the browser. This architecture includes presentation layer, function layer and data layer, which are placed in three independent units: Web browser, web server and database server Because the transaction logic processing is put into the web server, the pressure of the client is greatly reduced, the client is liberated from the heavy burden and the continuous requirements for improving its performance, and the technicians are liberated from the heavy maintenance and upgrading work. Moreover, it runs on the Internet, which makes the system overcome the limitations of space and region. It can access the system anywhere and realize monitoring anytime and anywhere.

From the current situation, B/S structure is more suitable for applications with little interaction between users and systems. For frequent applications of updating and interaction, it needs to integrate with traditional C/S structure to give full play to their respective technical advantages and better serve the monitor system. Simultaneous interpreting and testing are very important.