Keywords: CS system, power control, noise shielding, comparison and matching, calculation, fly, one, side, m, foreword, foreword, self-hardening, blade division, one type of horizontal vacuum sintering furnace, 93 years, designed by the South China University of Engineering and Metallurgical Equipment Corporation. Automatic furnace temperature control system.
Due to the technical conditions of the equipment at that time, the host uses a microcomputer-compatible ultra-small automatic control device composed of a compatible microcomputer and the company's own self-developed plate.
The system currently uses the following serious defects: The host has a long service life. In the aging failure period, frequent failures occur. The floppy drive color display can no longer be used normally because there are no replaceable parts. Once the system fails, the system software cannot be repaired. The operation of the problem is cumbersome, there is no Chinese prompt, each curve with oven temperature should be repeatedly input, no Chinese prompts, can not achieve the print control of a record of the collaborative operation of the vacuum control alarm function has failed the system anti-interference ability is poor, often crashes .
The temperature of the second zone of the furnace is always higher than the first three bands by a certain value and cannot be corrected.
In order to improve product quality and market competitiveness, strict process management, we must eliminate the original control system as a whole and replace it with a new type of popular IPC with standard configuration software and multiple input and output temperature intelligent controllers to achieve process requirements and temperature increase characteristics. The furnace temperature automatic control system design and control system hardware design is based on the technological requirements and the principle of economical and simple reliability. The system control scheme is shown in the National Nonferrous Metals Automation Technology and Applications Academic Annual Conference Proceedings Print Host Computer Ten Communication Card Vacuum Furnace Control Vacuum furnace controller temperature true temperature source voltage vacuum furnace controller temperature true temperature source voltage supply voltage vacuum temperature map temperature control system schematic diagram according to the control system to be collected by the analog and 1 / range and Polarity, determine the temperature transmitter's selection and matching process controller input acquisition methods, as shown below, the input and output signal definition and the range of the range of the analog input furnace temperature measuring element type dual platinum crucible thermocouple temperature transmitter output Total Vacuum Measure Output Signal One s Digital Input Start Button Three Band Temperature Controller Up and running.
Power failure recovery button Restarts the unfinished program when the controller is powered off.
The Process Recovery button clears the currently running process curve and the program returns to the initial unoperated state.
If the cooling water flow detection switch is in the state of a cooling water detection switch, the computer gives an alarm message, and the execution of the program is suspended, and the output is completely turned off.
After the fault is completed, press the power button again to resume the unfinished program.
Switch output bell road, relay control.
Furnace temperature alarm signal lamp, red, automatic status indicator lamp, manual status indicator lamp, vacuum degree upper limit warning indicator lamp, process recovery indicator lamp, insulation indicator lamp, water shortage warning indicator lamp, national non-ferrous metal automation Technical and Applications Academic Annual Gaeling) Proceedings of the Analog Output Common-circuit output to a thyristor regulator for zero-crossing triggered external input signals.
According to the above requirements, the design of the temperature process controller block diagram shown in the furnace temperature vacuum degree daily map, solid keyboard array digital display start power recovery process recovery drive conversion cooling water flow switch output lamp level conversion host computer reset Circuit power module expansion diagram temperature controller hardware block diagram PC software design vacuum sintering furnace computer control system management software running on the Xg platform, intuitive and friendly operation interface.
With a few clicks of the mouse, the management and operation of the vacuum sintering furnace controller can be completed.
The host computer software mainly realizes the following functions: real-time display of operating parameters table running curve of each vacuum furnace controller, and the operation status of each vacuum furnace controller is clear at a glance.
Real-time monitoring of the operating parameters of each vacuum furnace. When the parameters are abnormal, it automatically switches to the alarm screen.
Historical alarm records are stored on the computer for later query printing.
Provides query print function of historical running curve.
The real-time bar chart flow chart visually displays the current operating parameters of the vacuum furnace.
Read online to modify the operating curve of the vacuum furnace controller.
The technology curve can be stored in the computer, eliminating the need for future cumbersome entry.
Read online to modify the operating parameters such as vacuum oven valve opening.
Rights management provides two-level password protection to prevent unrelated people from using related functions.
The software provides database maintenance.
PC software flow chart as shown in the National Nonferrous Metals Automation Technology and Applications Academic Conference 8 Proceedings of the main control screen Workers' Assistant Assistant Supervisor and maintainer When the time of the month, the history of the month, the history of the arts, the time limit, the change of the law, the change of the side of the police, the movement of the limit, the flow of the tube, the secret library, the British setting, the status line, the police, the program code, the dimension, the geisha, the number, the table, the record, the guardian, the white noise, Seven sets up the line of inquiry line, set the diagram of the upper computer software flow chart temperature controller software design temperature controller software using single-chip macro assembly language programming, call the standard ID module and various functional function module technical difficulties and solutions The original system thermocouple leads were unshielded.
In this transformation, the original cable was still used initially.
However, in actual use, the detected temperature signal always drifts and fluctuates greatly, and the cause cannot be found. It is believed that the modular temperature transmitter is unstable and the anti-interference ability is poor.
However, the Fluke-type digital oscilloscope was used to check the thermocouple input of the modular thermostat and found that the interference signal applied to the thermocouple was the maximum input signal of the Das type thermocouple and the interfering signal had reached the measurement signal. A full scale 40 thermocouple sampling lead is obviously not available.
After the use of four-core shielded cable as a thermocouple lead (type thermocouple without compensating wire connected to the temperature change input to solve the problem.
The original design was controlled separately for the three belt temperatures and there was no connection between them.
However, in actual use, it is found that the vertical position of the thermocouple installation cannot be completely guaranteed, resulting in that the temperature of one to three zones cannot be completely uniform, and the temperature in the middle zone is always higher than that of one or three bands.
And even if the middle belt is not heated, it is still at a fixed temperature.
After careful inspection of the furnace, the above reasons were discovered.
Considering that the temperature of the three belts has a strong co-occurrence relationship, an algorithm must be used to resolve the problem of inconsistent temperature in the three belts.
After modifying the temperature process controller program, adding the comparison and matching operation, the problem was solved.
The specific approach is that after the computer is automatically put into use, the computer will always check if the temperature of the furnace is the same.
In the following, when it is found that the temperature of the two belts is higher than any one of the three belts, the two belts immediately stop heating until the temperature of one of the three belts is higher than that of the second belt, and the second belt resumes the ID adjustment when the temperature is Above that, all ones and three bands use work regulation, so as to ensure that the furnace temperature rises to a predetermined value and the temperature of the three belts is uniform.
Add 0 national non-ferrous metals automation technology and application of academic difficulties) papers to develop conclusions and promote the application program.
The two-stage distributed system composed of a monitoring and management computer and a process controller is in full compliance with the actual conditions of the vacuum sintering furnace, can effectively control the furnace temperature and handle various abnormal conditions, and has high reliability, high control precision, and control risk dispersion. , Easy operation, low investment, easy maintenance and many other advantages.
The small modular temperature measurement is obviously superior to the traditional temperature transmitter temperature measurement, and has many advantages such as small volume, low power consumption, high accuracy, high response, and good reproducibility. It is an ideal upgrade for other temperature measurement devices of the company.
The chemical index of the automatic temperature control and sintering of the computer is the same as the traditional temperature control, and the magnetic force distribution is more uniform, which can fully meet the needs of the company's old vacuum sintering furnace.
Since many blade products of Noblehard have to undergo vacuum sintering, the vacuum sintering furnace is more successful than the automatic temperature control reconstruction of the vacuum furnace of the blade factory. Its control scheme can be widely applied to other high and low temperature sintering furnaces. Promote and apply to the special line vacuum sintering furnace of the wear-resistant parts factory and obtain better results. Only slightly modify the layout of the control panel and the button definition.
Especially for some occasions where the temperature control range is strict, the working environment is harsh, and there are many interference factors, the computer is used to automatically control the temperature to modify the temperature control of traditional analog instruments. It also has less investment, quick effect, high efficiency, and product market competition. Strengthen and many other advantages.
References 1] Sun Hanfang, Xu Aiqing.
The Principles and Applications of a Series of Microcontrollers [Beijing Beihang University Press, year.
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