Design and implementation of automatic control system for ironing machine based on single chip microcomputer

This paper introduces the automatic control system of ironing machine based on single chip microcomputer, and gives the hardware and software design and implementation of the system. The DMF50174 display module and TL549 serial A/D converter make the system have a high cost performance. The on-site operation effect is good, and it has produced good economic and social benefits.
China has a clothing consumption market with a population of 1.2 billion, and it is also a major clothing exporter. With the increasing demand of the ready-made clothing market in recent years, small clothing production enterprises have developed very rapidly, and the demand for small ironing systems is increasing. Most of the original small ironing machines are manually controlled equipment, which requires high operating experience of operators. Due to the different operating levels of operators, product quality problems often occur, and the damage rate is very high. In order to meet user needs, we designed an ironing control system by ourselves. The ironing machine uses AT89C51 as the main controller and DMF50174 as the display module. It can realize the storage and modification of 10 ironing programs, and can arbitrarily change the operating parameters according to the different processes and fabrics, and can display the parameter settings of the ironing program in a graphical way. The system is also equipped with a temperature control system, which uses a TLC549 serial A/D converter and a linear temperature sensor to collect and control the temperature. The system can control the temperature valve according to the temperature range preset in the ironing program. During the ironing process, the system displays the parameter settings of each solenoid valve in a graphical manner on the LCD screen, and indicates the current system operation process with a highlighted scan line.
1 System General Requirements
The control machine uses ATMEL89C51 to form a single-machine control system. Each ironing process is roughly divided into the following steps: mold closing, hot pressing (2 times), upper steam spraying, exhaust, lower steam spraying, mold opening, etc. Sometimes a step may be executed differently in a process. The system should flexibly adjust the start time and length of each step. The system should also have a temperature control system so that the ironing temperature can be controlled as required to avoid damaging the fabric.
2. System overall design
2.1 Solenoid valve control part
Each step of the ironing machine is controlled by a different control valve. The system has a variety of valves such as mold closing valve, pressure valve, steam injection valve, steam extraction valve, temperature control valve, etc. In order to facilitate expansion, the system has enough expansion space. This system uses P1 port as the control port, and also expands a 74LS377 for backup. It can control up to 16 solenoid valves to meet the system requirements.
Each control valve in this system is an AC solenoid valve. In order to avoid electromagnetic interference, photoelectric isolation is used.
2.2 Temperature control part
In order to control the temperature, a temperature acquisition part is designed, which uses a resistive temperature sensor PT100 and TI's A/D converter TLC549 with serial control to realize temperature acquisition.
TLC549 is a CMOS A/D converter based on an 8-bit switched capacitor successive approximation A/D converter. It is designed to be able to serially interface with a microprocessor or peripheral device through 3-state data output and analog input. The TLC549 uses only the input/output clock (I/O CLOCK) and chip select (CS) inputs for data control. The I/O CLOCK input frequency of the TLC549 can reach up to 1.1MHz.
The TLC549 provides an on-chip system clock, which usually operates at 4MHz and does not require external components. The on-chip system clock makes the operation of internal devices independent of the serial input/output timing and allows the TLC549 to work as required by many software and hardware. The I/O CLOCK and the internal system clock together can achieve high-speed data transfer and a conversion speed of 40,000 conversions per second for the TLC549.
Other features of the TLC549 include general control logic, on-chip sample-and-hold circuits that can work automatically or under microprocessor control, high-speed converters with differential high-impedance reference voltage inputs, easy ratiometric conversion, scaling, and circuits isolated from logic and power supply noise. The design of the entire switched capacitor successive approximation converter circuit allows conversion within less than 17μs with a maximum total error of ±0.5 least significant bit (LSB) accuracy.
2.3 LCD display
The system is equipped with a membrane keyboard to modify the control program and set up the system. For ease of operation, the system uses an independent LCD display system that can display the system temperature, the status of each control valve, the system operation status, etc. in real time.
The system uses the advanced dot matrix LCD display module DMF50174NB-FW from Japan OPTREX Company and the SED1330 LCD display controller from Japan SEIKO EPSON Company.
The DMF50174NB-FW LCD display module has the characteristics of high sensitivity, high reliability, low power consumption, long life, high brightness, etc. It is a 320×240 dot matrix. The module has two display modes: character and graphic. The display font is 8×8 dot matrix, which fully meets the requirements of industrial production.
SED1330 is an advanced character and graphic LCD display controller. It is the most powerful one among similar products. It has the following features:
?SED1330 is not only applicable to 8080 series MPU interface, but also to M6800 series MPU interface. It has two pins, SEL1 and SEL2, in the interface part as the interface function conversion setting of MPU.
SED1330 has a powerful I/O buffer in the interface part of MPU, avoiding the status check items of general controllers. MPU can access SED1330 at any time without asking the "busy" flag.
SED1330 has a rich instruction set, and most instructions have parameters, up to 10 parameters. SED1330 instructions can not only realize the synthesis display of the contents of two display areas according to different logical relationships, but also the synthesis display of the contents of three display areas. Through the synthesis display, character and graphic mixed display, character text feature display, flashing display and half-color tone display can be realized. The display data sent by SED1330 to the LCD module is transmitted in 4-bit parallel mode, which greatly improves the ability to control the dot matrix LCD device.
3 System software design
The system software adopts modular design and is divided into the following parts: LCD control module, parameter setting module, ten separate ironing program settings and parameter display modules, machine operation status display module and temperature acquisition, control and display module.
In summary, the ironing machine control system designed and implemented in this paper has high practical value. At the same time, the functions and usage methods of DMF50174 LCD, SED1330 LCD controller and serial A/D converter TLC549 are introduced. This system is now used in Shanghai Weijie Garment Equipment Factory. After a long period of actual testing, the system performance is good.