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Research and Development of Automatic Control System on Material Split Packing and Packaging Integrated Machine Kai Yang1, a, Zhongshen Li1, b and Lei Zhang1, c 1College of Mechanical Engineering and Automation, Huaqiao University, Xiamen, 361021, China , , Keywords: Automatic Control System, Split Packing, Packaging Machine, LPC2478, C/OS-II. Abstract. In order to meet the high speed, high precision, high reliability of the packaging machine, a novel control system is provided. In the hardware, the main circuits consisted of main processor module, memory module, temperature measurement and control module, input signal detection module, material split packing module, output driver module, human-machine interface module, system monitor module, power module and JTAG debug module, etc. In the software, the multi-tasking operating system C/OS-II and the graphical user interface C/GUI were successfully transplanted into LPC2478. Then an experimental platform was established. And many control tasks, including automatic measurement, making bags, loading, transferring, pumping vacuum, sealing and data display, were automatically and continuously executed on the platform. Finally the results show: the machine can package 30 packets (5 g per packet) in a minute; the packaging errors 0.2 g; the packaging qualified rates 93%. In conclusion, the system performance is good. Introduction With peoples living standards improving, higher requirements on material packaging are put forward. Some materials, such as food, medicines, not only require precise split packing, but also need vacuum packaging 1, 2. However, in the traditional mode of split packing and packaging, the work is very heavy, materials are easily contaminated, the packaging quality is not good, and the packaging efficiency is also low 3-5. To realize the integration of the automatic split packing and packaging and to meet the high speed, high precision and high reliability, a novel control system is urgently needed. Therefore, research and development of control system on the split packing and packaging integrated machine is of great significance. And an automatic control system of that machine based on ARM is provided in this paper. The overall design of the control system According to market demands and the split packing and packaging features of small granular materials, packaging processes, containing automatic measurement, making bags, pumping vacuum and sealing, are researched. The control system structure is designed as shown in Fig. 1. When the split packing and packaging machine is running, materials are precisely weighed by material split packing module, and then they are loaded into a ready made inner bag. After that, the bag is put into an outer bag and the whole bag is transferred into a vacuum chamber by manipulators,where air in the bag would be evacuated by air pump. Finally, the whole bag is sealed. During those processes, many solenoid valves are used to control various actuators. And, many sensors are used to detect the weight of the materials and location information.Thus, a complete closed-loop system is formed, and the system stability is improved. Hardware Design of the control system The hardware circuits are composed of main processor module, memory module, temperature measurement and control module, input signal detection module, material split packing module, Applied Mechanics and Materials Vol. 533 (2014) pp 294-297 Online available since 2014/Feb/27 at (2014) Trans Tech Publications, Switzerland doi:10.4028//AMM.533.294 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, . (ID: 17, University of California, San Diego, La Jolla, United States of America-18/05/14,08:44:26) output driver module, human machine interface module, system monitor module, power module and JTAG debug module, etc. Some of them are selected to introduce as follows. Main processor module. NXP Semiconductors designed the LPC2478 microcontroller, powered by the ARM7TDMI-S core, to be a highly integrated microcontroller for a wide range of applications that require advanced communications and high quality graphic displays. The LPC2478 can execute both 32-bit ARM and 16-bit Thumb instructions at the maximum 72 MHz system clock rate 6. The LPC2478 inputs signals from photoelectric sensors, magnetic switches, position sensors and infrared sensors. And control signals are output to control electromotors, solenoid valves, LCD, LED and buzzers, etc. Temperature measurement and control module. In this machine, molding inner bag and sealing outer bag are both operated in high temperature. The temperature is measured by K-type thermocouple and controlled by LPC2478. Circuits are shown in Fig. 2. The thermocouple reference function is given as follows: () ()2 190-126.9686 900 0 n i at i i EKta e = =+ (1) And its inverse function is: ( ) 90 0 n i i i tD E = = (2) Where 90 t () is the centigrade degree of the thermocouple, and E (mV) is the corresponding electromotive force, 0 a, 1 a, i K and i Dare conversion coefficients 7. The heating resistor temperature is detected by thermocouples mounted thereon and amplified by operational amplifier OP07. Then the signals are converted from analog to digital. In accordance with the temperature control rules in LPC2478, the processed results are output to ULN2003 to control the start of the heating solid state relay YJGX-3FA. TH1+ TH1- ADC123_IN10 V5 C15 104 R16 100 R14 5.1k R11 5.6k R10 100 W1 200 R13 100 R7 10M V5 R81k R9 1k 6 - 2 + 3 74 V- V+ U8 OP07 V5 V-5 TH1+ R12 2k R15 100k TH1- Thermocouple 1 +C16 10u C18 104 D3 1N4148 1 2 CN2 HEADER 2 +C17 10u D0 1 D1 2 D2 3 D3 4 D4 5 D5 6 D6 7 GND 8 RC 9 D6 10 D5 11 D4 12 D3 13 D2 14 D1 15 D0 16 U14 ULN2003 YOUT8 OUT8 YOUT9OUT9 V33 YOUT8 L220 Y8 Heating resistor 1 1 2 - 3 + 4 SSR4 YJGX-3FA R59 200 OUT89 OUT89 Fig. 1 Control system structure Fig. 2 Temperature measurement and control circuits Material split packing module. The small granular materials are transferred into weighing hoppers with vibrating feeder, where their weight is detected by 3 Kg weighing sensors. Then the signals are converted by A/D converter CS5532. After that, the converted data is transferred to LPC2478 through SPI bus. The weighing module circuits are shown in Fig. 3. As a result of the differences between current weight and set weight and the change rates of them, LPC2478 outputs different frequency to control vibrating feeders. R27 4.7K V2.5 V33 C24 104J C28 104J C26 104J L2100uH L3100uH C23 104J C27 104J C25 104J C35 223J C36 104 C37 104 R28 4.7K R29 4.7K R30 4.7K V33 CY3 4.9152M PS1+ PS1- PS2+ PS2- 1 2 3 4 5 6 7 8 9 10 CN4 HEADER 10 PS1+ PS1- PS2+ PS2- V2.5 C30 104J C34 104J C32 104J L4100uH L5100uH C29 104J C33 104J C31 104J Weighing sensor 1Weighing sensor 2 SPI_SSEL SPI_SCK SPI_MISO SPI_MOSI M1+ M1- M2- M2+ V-2.5 V-2.5 SPI_SSEL SPI_SCK SPI_MISO SPI_MOSI SPI_SSEL SPI_MOSI SPI_MISO SPI_SCK AIN1+ 1 AIN1- 2 AIN2- 19 AIN2+ 20 C1 3 C2 4 VA+ 5 VA- 6 A0 7 A1 8 OSC2 9 OSC1 10 SCLK 11 SDO 12 SDI 13 CS 14 VD+ 15 DGND 16 VREF- 17 VREF+ 18 U10 CS5532BSZ SPI_SSEL OUT2528 SPI_MOSI SPI_MISO SPI_SCK sheet4weight.SchDoc OUT024 sheet5Youtput.SchDoc sheet6power.SchDoc ADC123_IN1011 sheet3temperature.SchDoc IN1016 IN17 sheet2Xinput.SchDoc OUT2528 SPI_SSEL ADC123_IN1011 IN1016 OUT024 IN17 LCD_R04 LCD_G05 LCD_B04 LCD_CK LCD_FP LCD_EN LCD_LP TP_DI TP_CK TP_DO TP_CS TP_IRQ nDISPOff SPI_MOSI SPI_MISO SPI_SCK sheet1main.SchDoc LCD_R04 LCD_G05 LCD_B04 LCD_CK LCD_FP LCD_EN LCD_LP nDISPOff TP_IRQ TP_CS TP_CK TP_DI TP_DO sheet7LCD.SchDoc Fig. 3 Weighing module circuits Fig. 4 Modules cascade chart ARM human-machine interface module input signal detection module material split packing module temperature measurement and control module and control module output driver module system monitor module memory module power module JTAG debug module Applied Mechanics and Materials Vol. 533295 Module cascade. Most of signals are connected through direct coupling cascade, but signals among external sensors, actuators and module circuits are connected by photoelectric isolation coupling cascade to improve the stability and security of the control system. All module schematics and the overall schematic of the control system are drawn through professional drawing software. And modules cascade is shown in Fig. 4. Software Design of the control system The real-time multi-tasking operating system C/OS-II is introduced to design the control system software which is based on top-down structure model and modular design. At first, the system C/OS-II and the graphical user interface C/GUIare successfully transplanted into LPC2478 and well initialized 8, 9. Then the main program starts to create tasks. The control tasks are mainly made up of automatic measurement, making bags, loading, pumping vacuum, sealing and data display, etc. They are conducted by LCD program, touch screen program, the split packing program, temperature control program, packaging control program, the general input and output program, etc. Some of them are selected to introduce as follows. LCD program. The LPC2478 has its own LCD controller. The TFT true color LCD is used to display packaging information, such as packaging parameter adjustment interface, manual operation interface, material real-time weight, molding inner bag temperature, sealing outer bag temperature and fault message windows. The graphical user interface C/GUI runs in the system C/OS-II, and the human-machine interface is beautiful. The LCD control flow is shown in Fig. 5. Packaging control program. In the light of packaging control requirements, there are a lot of input and output signals to process. Input data, comprising various switching signals and sensor outputs, are used to detect in which packaging process the machine runs. Then corresponding control signals would be generated to open solenoid valve or to start electromotor by LPC2478. Finally materials will be packaged into packets. The packaging process flow is shown in Fig. 6. Fig. 5 LCD control flow chart Fig. 6 Packaging process flow chart Test experiments The hardware and the software were integrated into an automatic control system prototype as shown in Fig. 7(a). An experimental platform of the split packing and packaging integrated machine was established as shown in Fig. 7(b). In the main interface, the control system can display two groups of material real-time weight, molding inner bag temperature, sealing outer bag temperature and the settings of them. Users can adjust the settings through + - buttons. Besides, there are manual operation, packaging parameter adjustment, date and time display, etc. In the test experiments, packaging begin put inner bag into outer bag transfer inner bag outer bag ready? open outer bag pusher ready? chamber ready? rotate vacuum chamber put whole bag into chamber vacuum pumping seal the whole bag end Y N Y N Y N initialize coordinate, size N LCD begin draw pixel color under a width? calculate bitmap addresses under a height? get memory addresses end Y Y N 296Modern Tendencies in Engineering Sciences packaging weight and amount were measured in the settings of 5 g, 7 g and 15 g respectively in a minute. And each packet was weighed as shown in Fig. 7(c). Then, the material weight of all packets was calculated and recorded. Measurement points and weighing results were shown in Fig. 7(d). The long-term statistical results show: the machine can package 30 packets (5 g per packet) in a minute; the packaging errors 0.2 g; the packaging qualified rates 93%. 051015202530 0 2 4 6 8 10 12 14 16 Weight (g) Measurement point (a) (b) (c) (d) Fig.7 (a) Circuit board of the automatic control system, (b) experimental platform, (c) weighing packaged materials, (d) measurement point and weighing result chart Conclusions In compliance with the split packing and packaging requirements of small granular materials, an automatic control system is researched and developped. The main conclusions are: a) the hardware and the software of the control system are designed, the real-time multi-tasking operating system C/OS-II and the graphical user interface C/GUI are researched and successfully transplanted into LPC2478. b) an experimental platform of the split packing and packaging integrated machine is established. Many control tasks are automatically and continuously implemented on the platform. c) the inner bag packaging and the outer bag packaging are completed by the machine. And the appearance of the packaged products is consistent. Th