The Application of PLC in the automatic Packing Machine Control System Lixia Guo a, Zhengzhong Li b

Transcription

1 Advanced Materials Research Online: ISS: , Vols , pp doi: / Trans Tech Publications, Switzerland The Application of PLC in the automatic Packing Machine Control System Lixia Guo a, Zhengzhong Li b School of Electronic and Information Engineering Chongqing University of Science and Technology Chongqing, China a b li_zhengzhong@126.com Keywords: Packing machine; Programmable Controller (PLC); Control system; human-computer interface Abstract. This paper analyses the working process of small vertical automatic packaging machine, the overall solution of the automatic packaging machine control system based on PLC has been put forward. The design of hardware and software structure of PLC control system has been expounded emphatically. The control system human-machine interface and control procedures flow charts have been given. 1 Foreword The control system is an important part of the packaging machinery, its role is to control and coordinate the entire automatic working cycle, including: to make a variety of packaging movement complete in a certain order; to regulate and control the necessary pressure,temperature,time and speed ; to achieve automatic security protection, automated metering and counting ; to control the material supply and the automatic fault alarm. Conventional control system has the following: mechanical type, gas (liquid) pneumatic type and Electric control type and so on. [1] Electronically controlled type is the most widely used. Early electronically controlled control system mainly use the relay contactor circuit and the methods controlled by the instrument, and its lower level of control has been difficult to adapt to the control requirements of the modern food packaging. The modern automatic packaging machine required to complete a variety of packaging items, accurate positioning and high-speed packaging. Automatic packaging machine control system based on PLC and touch technology can better meet the requirement of packaging production and improve production efficiency. PLC has powerful, programmable, intelligent features. According to production requirement of process program, it can direct control the equipments. The touch referred to as the PT, is a high-tech man-machine interface designed specifically for PLC applications, with a powerful display and manipulation capabilities, to monitor the production site. At present, PLC and touch control technology has become an important industrial area of the control method. This article focuses on based on PLC automatic packaging machine control system, the control system of the hardware design and software design are described in detail. 2 The Small fully automatic packaging machines working process The small automatic packaging machine is packaging equipment with the function of bag making, filling, sealing, date printing, cut off bag film, and finished counting. While automatically quantitative partly completed materials convey, loading, metering and feeding and etc. The working process is as follows: After the packaging film has been installed according to specified requirements, the packaging film is driven by stepping motor driving synchronous belt wheel. When the Packaging film through the printer, it can automatic to print in need of the production date. The film is lapel molding, through the longitudinal sealing device of longitudinal sealing will film made bag cone, the seal the bag tube used the under seal. The material through the material level measuring hopper, the control system to be automatic control feeding machine rev. Stop the materials in the hopper to keep a certain height to form a stable material pressure to ensure the stability of the measuring accuracy. Material All rights reserved. o part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-08/04/16,21:54:11)

2 1814 Advanced Information and Computer Technology in Engineering and Manufacturing, Environmental Engineering filling measuring cup, beyond the edge of the material is scraper scraping the flat, when the material depending on the proportion of change, but through the rotating measurement adjusting mechanism hand wheel change measuring cup volume, to achieve the measurement accuracy. material filling measuring cup, beyond the edge of the material is scraper scraping the flat, when the material depending on the proportion of change, but through the rotating measurement adjusting mechanism hand wheel change measuring cup volume, to achieve the measurement accuracy. Material feeding tube through into the bag film on the seal, the under seal, and go after the completion of the paper bag process, equipped with the material of the bag film through the self-respect, automatic fall into the sliding plate output machine. 3 PLC Control system design 3.1 Control system overall scheme design Based on the analysis of the working process of packaging machine, its control process is a typical sequence control, considering packing machine has complicated operation, sensor, interference characteristics, and PLC has high reliability, strong control function, easy to program, so using the programmable controller as the main controller. Consider to make the user convenient operation, to achieve flexible packaging machine control, selection of man-machine interface as operation, the touch menu of application software on the machine's parameters in track adjustment. Electronic display and cutting length, packaging, filling and packaging yield, net content, stick out a mile. Standard color code tracking photovoltaic system can absolutely guarantee product packaging printing patterns correctly. In addition, the machine can work on the process of on-line state monitoring and fault diagnosis analysis, if a problem occurs, automatic shutdown, and display the fault causes and solutions. Based on the complex structure of the vertical bag forming machine, adjusting mechanism, and low accuracy of packaging, generally within ± 2% -3% and some are still more than ± 3%. Packing speed low, mechanical and general servo control forming machine power consumption is big, sealing not strong enough, especially the trademark printed with color patterns cannot be accurately, it is because of wrapping the actual movement velocity and the expected has error, the accumulated will make a mark position changes, the urgent need to improve. Based on this point, the system selects the stepper motor control, intermittent packaging machine using a stepper motor for membrane, the reliability can be improved. Before packaging films used for sending the crank and connecting rod mechanism with intermittent pull mode, the structure is complex, adjustment difficulty. Especially when you need to replace the product, not only the adjustment difficulties, and packaging waste a lot of film. Stepper motors and pull the wheel with direct links with Latin America, not only structure has been simplified, and it is very convenient for adjusting, as long as through the buttons on a control panel can be achieved, thus saving the adjustment time, but also saves the packaging materials. In the intermittent packing machine, packaging material feeding control can be used in two modes: the length of the bag control mode and color control mode. Bag length control model applies to without color packaging film, by a predetermined stepper motor speed method, changing air ratio setting through the touch can be achieved. Color models are equipped with photoelectric switches, photoelectric switches detect color position, when the detected color, a control switch signal, stepping motor according to the signal, stop, after a certain period of time delay, then turning for the film, go round and begin again, guarantee in accordance with the mark position fixed length for film. Control system structure diagram as shown in figure 1.

3 Advanced Materials Research Vols HMI PLC Photoelectric detection Printer For the film motor Main motor Bag pulling stepper motor 3.2 PLC model selection The selection of PLC basic principle is to satisfy the control requirements under the premise of ensuring system, reliable work, convenient maintenance and use, and the best price performance ratio. According to the machine control requirements, due to its process is relatively fixed, better environmental conditions, a smaller amount of repair, so the selection of integral structure of PLC is the best; For the control of machine process, the main control objects are: the main motor (using three-phase asynchronous electric motor), paper (single phase capacitor motor), (bag pulling motor stepper motor), temperature control. For the three kinds of control object, main motor, paper feeding motor output is the relay output, bag pulling motor output is transistor output, These are all belong to the switch quantity control, and the temperature control is the analog control, the need for dedicated analog module. Bag pulling motor (stepper motor) require frequent on-off, based on this point, I choose the output transistor output PLC. For the temperature control module, select FX0-3A module. Based on the above points, the control system uses the Japanese Mitsubishi FX1-40MT produced by AC programmable controller, power supply, DC24V power input, transistor output.fx1 PLC is a series of Mitsubishi company in recent years the introduction of high performance small integral PLC, can achieve high speed operation, basic instructions every 0.08 microseconds. High speed counter, enclosing the internal components is very rich, is a very strong function of small PLC. Because of its compact structure, fast execution speed, powerful functions and higher capacity-price ratio, consistent with the system requirements. 3.3 Input output point distribution Automatic packaging machine process consists of bag forming, filling, sealing, cutting several parts, packaging machine control system input signal: start, stop, emergency stop signal, the safety door switch detection, packaging bags color detection, detection of long paper shortage, long bag pulling detection, quantitative filling portion of the return signal, material filling high stop detection signal. The output signals are: the main motor, paper feeding motor, pulling the bag of step motor and its related instructions. The control requirements, and based on the whole control system total cost and spare considerations, the design and selection of input 24, output 16 PLC basic unit. 4 Control system software design Figure 1 Control system structure diagram Control system software consists of two components: human-computer interaction interface and PLC control programs. Human-computer interaction interface program complete the dialog between the operations officer with the PLC, mainly all and switch between each operation the corresponding to the various key actions the PLC program control Human-computer interface design PLC control system for an actual value, in addition to hardware and software, there should be suitable for the user easy operation and of human-machine interface. In recent years, software plays an increasingly important role of the human-machine interface system, its direct impact on the life of the

4 1816 Advanced Information and Computer Technology in Engineering and Manufacturing, Environmental Engineering software. Human-machine interface design quality, directly affect the users of the software product evaluation, thus affecting the competitiveness of the software product. Users can interface readily understand, observe and grasp the whole control system for operation, necessary or can be issued through the human-machine interface control system fault alarm, manual intervention. Man-machine interface, PLC information and computer Exchange, to input data, the PLC control system information command and control and PLC control system through human-machine interface, programmable terminals, computer last air control system data and related information to the user. From this interface fully embodies the I/O functions of PLC control system and user control to the operating system work. In summary, the so-called man-machine interface is an interface between people and between the PLC control systems. The operator can achieve the exchange of information and data processing with PLC control system by man-machine interface. The man-machine interface of the system selected is that Human Electronics in Shenzhen MT500 series touch. All s, designed by EB500 software, have welcome, splash, data display and parameter settings, alarm, and is mainly used for the packaging machine to set control parameter, starting and stopping the machine, Real-time data display, work status display and fault information display, and the realization of the role of communication with the PLC. After the EB500 software compiled correctly, it can be debugged using after the download from the PC to the touch. Figure 2 gives the main of control system. Welcome to the DXD type full automatic packaging machine June 18, 2012 Eight forty-five and 26 seconds Set Display Alarm June 18, 2011 Operation Out of paper PgUp Start Stop Manual Emergency stop PgDn Operation Set Display Alarm Exit Out of paper bag stuck Main motor Return (a)the main interface (b)operation interface June 18, 2011 Set Frequency setting Packing capacity Bag length setting June 18, 2011 Alarm display PgUp The number of preset bag PgUp PgDn Return Return (c)set and Display interface Figure 2 Control system interface 4.2 Control system design of the main program (d)alarm interface Automatic packaging system show the main process in Figure 3, first determine the transverse seal and vertical temperature reached the set temperature and the safety door is closed before the system work, and also used to detect the control error or not, if error, the program does not work properly, send out the alarm signal in order to exclude. ext do the manual and automatic state judge. If it is in manual, conduct Manual operation, if in automatic, conduct cycle program after setting the parameters.

5 Advanced Materials Research Vols Start Set temperature to Safety door closed Operation mode selection Alarm display Automatic operation Parameter set Cycle operation Manual operation Alarm display Running time ED Figure 3 System control flow graph 5 Conclusion The design of packaging machine control system, the PLC technology and man-machine interface, and the original by relays, contact device control system composed of more obvious advantage, mainly displays in through the PLC control stepping motor, improve the reliability of equipments, the use of PLC man-machine interface save the I/O points, the operation is the interface is simple, convenient; Produced a good economic benefits. Mitsubishi FX1 type PLC in small vertical all the application shows that the packing machine, it is a property prices are higher small programmable controller, is more suitable for small mechanical equipment of the electrical control system. 6 References [1] Fuyuan Lei, The design principle of automatic packaging machine Tianjing, Tianjin Science Press, April [2] Wanzhen Zhou, Hongbin Gao, PLC analysis and design application,[ M]. Beijing: Publishing House of electronics industry,juanuary 2004 [3] Qinglai ue, Inverter, PLC and touch integrated application technology. Machinery industry press, May [4] Liu chen, Xiaogang Li. The Application of PLC in packaging machinery [J ] packaging engineering, February 2004, (02). [5] Easy Builder 500, The use of manual Shenzhen Computer Electronics Company Limited

6 Advanced Information and Computer Technology in Engineering and Manufacturing, Environmental Engineering / The Application of PLC in the Automatic Packing Machine Control System /