Abstract : This article introduces how to design an artificial rainfall simulation control system based on the control characteristics of the system, using advanced KingSCADA monitoring software and a programmable computer controller (PCC) with a time-sharing multi-tasking operating system and a user-friendly programming platform. Keywords : PCC; control; artificial rainfall simulation; KingSCADA CLC Number: TP27 Document Code: A Article Number: 1008-1151(2005)10-0084-02

The rapid development of science and technology has brought revolutionary changes to current industrial automation. Traditional system control methods relying on relays and discrete electronic circuits are far from meeting control requirements. Therefore, PLC control technology emerged, leading to a qualitative leap in industrial control technology worldwide. However, its simple logical sequence control function and the lack of transparency in the control process still have shortcomings in some areas. To address this, this paper proposes a new design concept for an artificial rainfall simulation system, using B&R as the lower-level control system and KingSCADA as the upper-level configuration controller. This significantly improves the stability, monitoring, and effectiveness of the control process, effectively solving the problem. 1. Introduction to Artificial Rainmaking Device   This standard runoff field artificial rainfall simulation system is built on a natural slope, approximately 10m high. 96 X-shaped downspout nozzles are evenly distributed within a 20m × 5m area. Each nozzle consists of four sets of different nozzle orifice diameters, divided into 24 groups, each controlled by a solenoid valve. An electric flow control valve and a pressure gauge are installed on the water supply pipeline. Adjusting the flow control valve controls the pipeline flow rate and displays the current pipeline pressure. By controlling the flow rate in the artificial rainfall supply pipeline and the artificial rainfall nozzles, the system simulates artificial rainfall processes of varying intensities, distributions, and durations. The system provides real-time, accurate, and effective raw data for simulating the effects of different rainfall intensities, durations, and soil moisture content on soil infiltration, as well as the movement of soil moisture during rainfall. The implementation of this system will undoubtedly contribute to the development of runoff research.   2. System Hardware Configuration   2.1 Introduction to Programmable Computer Controllers (PCCs) .   The Programmable Computer Controller (PCC) was introduced to the industrial control field in 1994 by B&R Automation AG of Austria. It combines the features of an Industrial Control Computer (IPC) with those of a conventional Programmable Controller (PLC). Both in terms of internal hardware functionality and the ease of programming and development, it represents a significant advancement over conventional PLCs. The PCC's hardware and software have the following characteristics: 2.1.1 The CPU module adopts a multi-processor architecture. 2.1.2 A qualitative time-sharing multi-tasking operating system. 2.1.3 Modular structure, flexible system configuration, and easy installation. 2.1.4 Large program storage space. 2.1.5 Advanced programming languages. 2.2 System Composition and Functions.   Based on the characteristics of the artificial rainfall simulation control system, this system uses an Advantech industrial control computer as the host computer and B&R PCC-2003 series modules as the slave computers. The host computer uses an IPC2000 with the B&R Automation Studio V2.40 operating system installed; the slave computers use high-performance B&R PCC-2003 series programmable computer controllers, including the CPU474, analog input module AI774, analog output module AO352, and digital mixed-signal module DM465. Communication between the host and slave computers uses a CAN bus or RS232 bus. The system hardware configuration is shown in Figure 1.
Figure 1 shows the system hardware configuration. The entire system adopts a two-level distributed upper and lower computer structure. The upper computer system's human-machine interface can monitor the entire process and has functions such as pressure status display, animated rainfall simulation, and control and display of the opening of pipeline pumps, solenoid valves, and flow control valves. The lower computer consists of a B&R 2003 series programmable computer controller. The CPU module communicates with the upper computer and monitors the field equipment; the analog input module AI774 is connected to the pressure gauge and flow control valve to display pressure and valve opening; the analog output module AO352 is connected to the flow control valve to control its opening; and the output function of the digital mixed module DM465 is used to control the opening of the pipeline pump and solenoid valve.   3. System Software Design   Based on the requirements of the control system, we developed the system control software, which mainly consists of upper-level computer configuration software and lower-level computer control software. 3.1 Upper-level computer configuration software design .   The development platform for the upper-level computer configuration software is Kingview 6.0 software from Beijing Yacon Company. Kingview software was developed to meet the increasing demands for industrial automation and the need for communication between numerous control devices and process monitoring equipment, and it runs on Windows 9X/2000/NT. Kingview 6.0 software has a complete industrial graphics library, such as valves, pipelines, and simulated traditional display instruments, making the operating interface more user-friendly. The process flow and equipment operating status are clearly displayed, improving the safety and reliability of user operation. The system's monitoring interface mainly includes: the operation interface, the simulated rainfall hall interface, the regulating valve adjustment interface, the combination mode setting interface, and the solenoid valve combination interface. The operation interface is used to monitor the opening of pipeline pumps and solenoid valves, the opening degree of regulating valves, and pipeline pressure in manual mode; the simulated rainfall hall interface is used to simulate rainfall and monitor the operation of on-site equipment; the regulating valve adjustment interface has the function of adjusting and displaying its opening degree; the combination mode interface and the solenoid valve combination interface are used in combination mode, where the combination mode interface is used to set the rainfall time, regulating valve opening degree, and time period selection; the solenoid valve combination interface is used to control the opening of solenoid valves. 3.2 Lower-level control software design .   The lower-level control software utilizes B&R Automation's Automation Studio (AS) programming software. Automation Studio supports six standard development languages: ladder diagrams, instruction lists, structured text, sequential function charts, Automation Basic, and standard C language. Users can choose one or more languages ​​for programming within the same project as needed. Furthermore, the programming environment includes a rich library of functions and blocks that can be directly called as needed, significantly reducing the workload of developers. The lower-level control software design mainly includes upper-lower-level communication, manual mode, and combined mode task modules. The flowcharts for the manual mode and combined mode are shown in Figures 2 and 3, respectively. Figure 2: Manual Mode Flowchart Figure 3: Combined Mode Flowchart 4. Conclusion The artificial rainfall simulation control system based on PCC (Potentially Parametric Control System) studied in this paper was successfully applied in the Qiugou test area of ​​the Nanxiaogou watershed of the Yellow River Soil and Water Conservation Xifeng Management and Supervision Bureau in October 2004. Operational results show that the system has high reliability, flexible configuration, and high adaptability and scalability. References [1] Qi Rong, Principles and Applications of Programmable Computer Controllers [M], Northwestern Polytechnical University Press, Xi'an, 2003. [2] Beijing Asia Control Technology Development Co., Ltd., Kingview version 6.0 User Manual [Z], Beijing: Asia Control Company, 2001. About the Authors Sun Zhen (1991), male, from Xiping, Henan, is a master's student in the School of Automation and Information Engineering, Xi'an University of Technology. His research interests include detection technology and automation devices. Wang Huamin (1953), male, from Xi'an, Shaanxi, is a professor at Xi'an University of Technology. His research interests include detection technology and automation devices, and high-frequency induction heating power supplies.