Automatic dishwasher Control System Design
Abstract:Based on the functional requirements of the automatic dishwasher, introduced by SCM AT89LS8252and keyboard/display management chip designed automatic dishwasher HD7279A hardware control system design methods,using HD7279is given control of the keyboard and display hardware circuit,while the system is functional software modules and software flow chart.After debugging test of the system,which can effectively achieve the control dishwasher complete
automatic water,heating,cleaning and disinfection,and other functions.
自动洗碗机的控制系统设计
摘要：基于自动洗碗机的功能要求，介绍了用单片机ＡＴ８９ＬＳ８２５２和键盘／显示管理芯片ＨＤ７２７９Ａ设计的自动洗碗机的硬件控制系统的设计方法，给出了用ＨＤ７２７９控制键盘和显示的硬件电路，同时给出了系统软件和功能软件模块的流程图。该系统经过试验调试，可有效地实现洗碗机的自动控制，完成自动进水、加温、清洗、消毒等功能。
关键词：洗碗机；控制器；键盘／显示
Key words:dishwashers;controller;keyboard/display
1Introduction
As digital application of information appliances,dishwashers have broad access to masses of people in the family,so that people can work from home in the complex gradually liberated.
１引言
随着数字信息家用电器应用的普及，洗碗机已经广泛进入人民大众的家庭之中，从而使得人们能够从繁杂的家务劳动中逐步解放出来。
As a home automation equipment,such as dishwashers generally need to a chieve automatic control influent,automatic detergent,cold wash,automatic tem perature washing,cleaning,drainage,Disinfection,and the timing and fault alar m functions.From the point of view of control,a dishwasher usually need to meet Figure1shows some of the specific requirements,which involves the sw itching of signals there are two kinds of sensors is high,low signal detection, such as doors Switch,the water level and temperature regulation for the prote ction of trip switches,etc.;another solid-state relay switching control signals b y the strength of the signal voltage disconnect and loading,such as electromag netic inlet valve opening and closing,opening and closing the heater thermostat ,and instantly the heater to create a control box cleaning agents and disinfect
ants control box,and so on.Figure1in the analog signal used to achieve the following major aspects of functions:
(1)Temperature Sensor temperature/Xiaodaishui temperature detection;
(2)through the man-machine interface display,keyboard input and output,such as voice achieve temperature,washing process shows that the fault type and d isplay;
(3)According to user needs by setting button to select washing mode,and thr ough function keys launch-related functional;
(4)the use of statistical machine,cleaning agents and the use of disinfectants dose counting;
(5)Failure Alarm,as well as,washing complete the report.
作为一种家庭自动化设备，洗碗机一般需要实现诸如自动控制进水、自动加洗涤剂、冷洗、自动加温洗、清洗、排水、杀菌消毒，以及定时和故障报警等功能。从被控制量角度出发，一个洗碗机通常需要满足图１所示的一些具体要求，其中涉及的开关量信号有两种，一种是传感器的高、低电平信号检测，如机门开关、水位高低、温度调节保护器和行程开关等；另一种开关信号经由固态继电器控制强弱电压信号的断开和加载，如进水电磁阀门的开合、恒温加热器的开合、瞬间加热器的开合、清洁剂控制盒和消毒剂控制盒的工作等。图１中所涉及的模拟量信号主要用于实现以下几方面的功能：
（１）用温度传感器实现水温／消毒水温度检测；
（２）通过人机接口的显示输出、键盘输入和声音输出等实现水温显示、洗涤过程显示以及故障类型显示等；
（３）根据用户需要通过设置键选择洗涤模式，并通过功能键启动相关功能；（４）机器使用情况统
计、清洁剂和消毒剂剂量的使用情况计数等；
（５）故障报警以及、洗涤完成报告等。
2dishwashers control system hardware design
To address the above function and reliability,cost and ease of use factors such as maintenance,and the author of the design shown in Figure2dishwashers control system.
SCM system is the smallest and MCS-51compatible with the AT-MEL co mpanies low-power high-performance CMOS chip design AT89LS8252,k-chip
8-byte programmable flash memory storage system for the procedures to be ad opted by the SPI interface download programs;and2k bytes of EEPROM is used to store key parameters,such as the boot password maintenance,product serial number,the number of boot,washing setting parameters;256bytes of R AM used to store temporary variables.
In view of the dishwashers have more of the switching signal,therefore,the use of parallel design chips8255to expand the I/O interface,and to meet some of P1and P3I pin the use of its input and output ratio of21/14,wh ich buzzer from P1.3control.From the reliability point of view,part of the in put
and output using photoelectric isolation measures.Consider that part of the drive signal required by the larger drive current,therefore,the design uses po wer-driven devices ULN2803to drive.
There are two temperature acquisition programme:First,the use of thermal r esistance with a MAX150chip AD converter,and then deposited in the progra m memory in the form to achieve the current temperature;Second,the use of three-DS18B20temperature sensor for acquisition,direct access to the temperat ure data.In contrast,after a simple programme more economical.
LED display and keyboard use HD7279A3to control,the circuit sho wn in Figure3.HD7279A without external components can directly drive a tot al of eight vaginal LED digital pipe;corresponding pin DIG0~0~3digital output driver;pin SA~SG and DP is a paragraph corresponding to~g and the decimal point drive output can be independently controlled to decode/dec oding and attributes such as blanking and scintillation.
２洗碗机控制系统的硬件设计
针对上述功能及可靠性、成本和方便使用维护等因素，笔者设计了图２所示的洗碗机控制系统。
单片机最小系统采用与ＭＣＳ－５１兼容的ＡＴ-ＭＥＬ公司低功耗高性能ＣＭＯＳ芯片ＡＴ８９ＬＳ
８２５２设计，其中片内８ｋ字节在线可编程闪存用以存放系统程序，可通过ＳＰＩ接口来下载程序；而２ｋ字节的ＥＥＰＲＯＭ则用以存放关键参数，如开机维护密码、产品的序列号、开机次数、洗涤设置参数等；２５６字节的ＲＡＭ用来存放临时变量。
鉴于本洗碗机有较多的开关量信号，故此，设计中使用并行芯片８２５５来扩展Ｉ／Ｏ接口，以配合Ｐ１和Ｐ３口部分管脚的使用，其输出和输入的比例为２１／１４，其中蜂鸣器由Ｐ１．３控制。从可靠性角度出发，输入和输出部分都采用光电隔离措施。考虑到部分驱动信号所要求的驱动电流较大，因此，本设计选用功率驱动器件ＵＬＮ２８０３来驱动。
温度采集有两种方案：一是使用热敏电阻配合芯片ＭＡＸ１５０进行ＡＤ转换，然后通过存放在程序存储器里的表格来求得当前温度；二是使用三端温度传感器ＤＳ１８Ｂ２０进行采集，直接得到温度数据。相比之下，后一种方案较为经济简捷。
键盘和ＬＥＤ显示选用ＨＤ７２７９Ａ ３ 来进行控制，其电路图如图３所示。ＨＤ７２７９Ａ无需外围元件即可直接驱动８位共阴式ＬＥＤ数码管；引脚ＤＩＧ０～３对应０～３位数字输出驱动；引脚ＳＡ～ＳＧ和ＤＰ则对应于段ａ～ｇ及小数点的驱动输出；各位可独立控制译码／不译码及消隐和闪烁等属性。

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