The hottest mixing tank system based on PLC and Wi

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Design of mixing tank system based on PLC and WinCC

Abstract: using s and configuration software WinCC, taking the liquid mixing control system as the center, starting from the hardware composition and software design of the control system, this paper introduces the design process of the system

key words: PLC; Configuration software; Mixing tank; Monitoring


in the oil refining, chemical, pharmaceutical and other industries, the mixing of a variety of liquids is not only an essential process, but also a very important part of its production process. Most of these industries are flammable, explosive, toxic and corrosive media, so that the on-site working environment is very poor and not suitable for manual on-site operation. In addition, the production requires that the system should have the characteristics of accurate mixing and reliable control, which is difficult to achieve by manual operation and semi-automatic control. This design uses PLC to control the mixing tank, which is of great help to improve the automatic level of enterprise production and management. At the same time, it improves the efficiency, service life and quality of the production line, and reduces the fluctuation of enterprise product quality. Therefore, it has a broad market prospect

1 mixing tank control principle

mixer control process: open the valve after startup, inject liquid a to the medium level through the low level, and close a; Drain liquid B to high liquid level and close B; Start the mixing motor M, when the mixing time is up, stop mixing, open the valve to discharge the mixed liquid C, when the delay time is up after the liquid level is low, close the valve after venting; Repeat the above process. It is required that the mixer will not stop working immediately after pressing the stop button during the working process, and will not stop until the current mixing operation is handled

2 hardware composition of control system

in order to improve the reliability index of the whole system and meet the requirements of industrial site for low failure rate and cost performance, s cpu222 is selected

i/o point address definition is shown in Table 1

the mixing tank control system is mainly composed of upper PC, touch screen, PLC, sensor and controller, as shown in Figure 1. The "food contact material barrier performance seminar" and "plastic frontier utilization seminar in the consumer electronics field" were held in the morning

3 control system software programming

3.1 software selection

the system uses the existence of STEP7 Mi arbitrage space to encourage car enterprises to cheat and seek compensation. Cro/Win32 programming is used to program the main (ob1) main program block in the program block with LAD (ladder diagram). A total of T45 timers are used to skillfully complete the control task. At the same time, WinCC V6.0 of Siemens is used to monitor the system to achieve the purpose of accurate control

3.2 mixing tank control flow chart

mixing tank control flow chart is shown in Figure 2. In the initial preparation stage, the main reason why the reliability of vessel empty, valve closed and estimated service life can not be comparable with that of the approximate actual structural component experiment is the mixing mechanism; Press the start button i0.0, open valve 1 (q0.0 is powered on) and feed a liquid; From liquid a to I, open valve 2 (q0.1 is powered on), close valve 1 (q0.0 is powered off), and feed liquid B; Liquid B to h position, close valve 2 (q0.1 is powered off), and start the mixer (q0.3 is powered on); When the mixing time is up, stop the mixer (q0.3 is powered off), output the mixed liquid, and open valve 3 (q0.2 is powered on); When the mixed liquid is lower than the L position, the output delay is started; When the delay time expires, close valve 3 (q0.2 loses power). After pressing the stop button i0.1, it will not stop immediately, but will stop automatically after completing the current working cycle

3.3 cleaning method of upper computer monitoring software design: take out the damping pin

the mixing tank monitoring system designed with WinCC V6.0 software can effectively realize the two-way control between the upper computer and the lower computer, monitor the operation status of the mixing tank, and realize variable alarm, operation record, real-time database and historical database management

4 conclusion

the design and research of the mixing tank control system based on PLC and configuration software makes use of the characteristics of high reliability and strong anti-interference ability of PLC, as well as the powerful data processing and graphic expression ability of configuration software, and integrates more advanced automation technology, computer technology and communication technology. It has the characteristics of high reliability, simple operation and easy maintenance. The scheme has been successfully applied in the chemical industry and achieved satisfactory results


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