Application of the pyrotechnic control computer in

2022-07-27
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The application of industrial control computer in the control system of die casting machine this paper uses industrial control computer to complete the control system of die casting machine, designs the corresponding hardware circuit and compiles the control software. In order to improve the quality of die casting parts, it is proposed to use the adaptive fuzzy control theory to control the injection speed, an important parameter in the die casting process. The computer simulation results show that this control method is feasible

high pressure and high speed are the two major characteristics of the pressure casting process. The mold filling of the casting is intact and the contour is clear, which mainly depends on the injection speed (i.e. the injection process), while the internal quality and mechanical properties of the casting mainly depend on the pressurization effect (i.e. the pressurization process). In order to obtain high-quality die castings, All process parameters in the die-casting process must be properly controlled according to different situations. "If there is capital chain fracture in Longmei, such as injection pressure and injection speed, etc. compared with foreign high-tech, domestic die-casting technology is still very backward. In view of this situation, the State Planning Commission has established" j11280 die-casting machine system "as one of the key scientific and technological projects in the eighth five year plan

j11280 28000kN (the horizontal cold chamber die casting machine is a new product designed and trial produced by domestic die casting machine manufacturers. After the control system is completed, the user manufacturer is very satisfied with the performance of the machine. It has passed the appraisal of the State Development Planning Commission. It is the largest and most advanced die casting machine in China.

1. Overview of j11280 horizontal cold chamber die casting machine

1.1 machine components

j11280 horizontal cold chamber die casting machine is mainly composed of body, electrical system and ejector Structure, combined mechanism and sometimes hydraulic system are composed of five parts. The working principle diagram of the injection system is shown in Figure 1

Figure 1 Schematic diagram of the injection system of the die casting machine

1.2 analysis of the working mechanism of the die casting machine

the process of completing a casting is as follows: dynamic 1 core inserting - Dynamic 2 core inserting - mold closing - low pressure mold closing - system pressure locking - mold closing completion - static core inserting - slow pressing - one fast - two fast (simultaneous pressurization) - (the cooling time is up) static core pulling - mold opening - Dynamic 2 Extraction - Dynamic 1 Extraction - delay before ejection - delay after ejection - pressure back - ejection - return to the original position - delay unloading. Repeat the cycle for casting production. Each action process of the die casting machine can be controlled by changing the state of the hydraulic system through the on-off of the solenoid valve

2. Hardware system design of industrial computer controlled die casting machine system

2.1 overall design of hardware system

the die casting machine control system is mainly composed of industrial computer, switch input board, switch output board, analog input board, relay board and peripheral auxiliary circuits. Its structure block diagram is shown in Figure 2

Figure 2 control system structure of die casting machine

the industrial control computer mainly completes the sending of control instructions and the calculation of analog quantities. The specific control process is as follows: the switch signal sent by the travel switch and the control button indicates the current action of the die-casting machine, enters the industrial control computer through the switch input board, detects the working state of the die-casting machine by regularly reading the corresponding port of the industrial control computer, forms the corresponding switch output through logic operation, and then controls the on and off of the solenoid valve of the die-casting machine through the output relay board to control the action of the die-casting machine. In order to prevent interference, switching value input and output adopt photoelectric isolation input and output, which are 32-channel input and 26 channel output

2.2 industrial computer configuration

industrial site conditions are relatively poor, and the most common problems are dust, radiation, electrical interference, etc. In some environments, it is necessary to prevent moisture, shock and impact. The universal industrial computer series produced by Contec company is selected for the design. It has high reliability power supply device, high-power double cooling fan refrigeration system, all steel standard chassis with filter, shock absorption and reinforcement strip device, and 14 slots for i/o expansion, which can meet the requirements of production environment. See Table 1 for details. Table 1 industrial computer configuration

2.3 system simulation

because the system has many non-linear links, such as hydraulic oil, servo valve, etc., which brings certain difficulties to the theoretical analysis and optimization design of the system, the system can only be simulated with the help of computer. Because the resistance of the cylinder piston in the injection process is very small, it is approximately considered that the injection speed is proportional to the volume of hydraulic oil entering the cylinder, that is, the proportional link. Refer to relevant manuals to determine parameters. The system simulation results are shown in Figure 3

Figure 3 system simulation diagram

3. Software system design of die casting machine controlled by industrial computer

its program modules include: die casting machine driver module, digital quantity detection module, status display module, speed pressure curve display module, fault diagnosis module, parameter adjustment module, printing module and help module

Borland c++ is used as the programming language in the design of this system. Interrupt in interrupt service program_ The main function of app() function is to form a new control byte from the current input state according to the logic rules and send it to the corresponding output port, so as to drive the corresponding solenoid valve to gain or lose power and achieve the purpose of completing the die-casting process. Thus interrupt_ The app() function is mainly composed of three sequential parts: reading the input status, performing logical operations to form control bytes, and outputting control bytes. Its design evolved from PLC ladder diagram. Such as PLC ladder diagram 4

Figure 4 PLC ladder diagram

its corresponding conversion program is as follows:

if ((r0[0]& "r0[7]) &&&counter[tc31] TC)‖Ro[1])

R17[4]=1;

else

R17[4]=0;

if (R16[7]&&!R0[3])

Start_ counter(TC31);

else

End_ counter(TC31);

counter is a data structure as follows, which corresponds to the finisher of the first ground test phase of the world's largest composite aircraft:

structure counter

{int TC;/* indicates its contact */

int use;/* indicates whether the counter is currently started */

unsigned long counter_max;/* timing time */

unsigned count;/* records the value */

} counter

delay disconnection: when e=1, = 1, unt increases by 1 every certain time, and count_ When Max is equal, =0, stop counting

when the delay closing is e=1, = 0. When the timing time is up, make = 1 and stop counting

die casting machine has two working mechanisms: adjustment and linkage. Each working system has a certain action sequence. Therefore, there are two design schemes:

1) step by step design scheme: under this design scheme, first of all, it is necessary to study the C flow chart of PL controlling the action of die casting machine to improve the quality of recycled materials, and then deduce the executable conditions of each action. In the process of program design, based on the current working state, control the corresponding next action

2) design scheme according to PLC control mechanism: under this working mode, only PLC ladder diagram needs to be converted into corresponding program language, and then the driver program design is simulated according to the working mechanism of PLC

the PLC flow chart adopted in the second working scheme has been running on site for a long time, which is easy to ensure the correctness of control, and is easy to be understood and mastered by on-site technical workers. Therefore, the second design scheme is adopted

plc's basic working mode is to adopt periodic working mode, i.e. scanning working mode, under the control of system software. Its operating system is a small real-time system software with its own structure and characteristics. During each scanning, PLC not only reads the status of each input point, but also outputs control signals by user logic, but also carries out fault self diagnosis and processing and communication requirements with programmers, computers, etc

4. Conclusion

the system designed in this paper has the following characteristics: ① with 2000 times of state detection per second, it can detect the instantaneous change of state and control it in real time; ② With the functions of status monitoring, fault diagnosis, pressure and speed curve display in the system, users can have a timely and comprehensive understanding of the working status of the system; ③ The system has a simple program interface, users can easily carry out the secondary development of the system; ④ It has good user interface and simple system operation

references

[1] Dai Zhongda Fundamentals of automatic control theory Tsinghua University Press, 1991

[2] Jin Haiming, Luo Yunlin Microcomputer measurement and control technology Coal Industry Press, 1995

[3] Zhu Jing Fuzzy control principle and application China Machine Press, 1995

[4] John rland c++ programming guide Electronic Industry Press, 1998 (end)

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