中文2528字AT89C51 single-chip temperature-controlled watertemperature control systemEarly contact thermometers for chemical water temperature thermostat shortcomings, this paper introduces an approach based on AT89C51 single-chip microcomputer-based controller, combined with integrated temperature sensor AD590J composed of constant temperature water temperature control system.Chemical, chemical experiments and research on water temperature requirements of high performance and accuracy, the current market face chemistry, chemical experiments and study the high price of heated water systems. In this paper, the design of single-chip component AT89C51 from the temperature control system for people with low-cost, high precision, intelligent control, etc.The water temperature of the performance indicators are: Temperature range: 0 ~ 1O0 ℃; temperature range: 0 ~ 99.9 ℃; temperature: 0.4 ℃; heating power: 1000W.Part of the hardware circuitAT89C51 selected as the system CPU, it is a low-power, high performance, 4kB flash chip programmable / erasable read-only memory 8-bit microcontroller COMS.Block diagram of the system AT89C51 single-chip by chip, IO expansion port 8255 chip, 8032 chip digital-to-analog conversion, analog-to-digital conversion chip 0809, keyboard control, status indication circuit, sampling circuit temperature thermostat control circuit, driver circuit and display circuit, such as group into.1.1 temperature sampling circuitTemperature sampling circuit using AD590 current-mode temperature-sensitive device of its stability and linearity are better. When in AD590 for the current 273.2uA, temperature increase 1℃, the current increase in 1uA. The current is converted to voltage signal by analog-to-digital converter ADC0809, AT89C51 single-chip temperature monitoring and conversion. One resistor R measurement using a low temperature coefficient of resistance, temperature coefficient of 10 x l0_6 / ℃. When monitoring the temperature of lO0 ℃when generated in the resistor voltage 18.66V about, when the temperature is 0 ℃when generated in the resistance of about 13.66V voltage, that is, at a temperature of 0 ~ 1O0 ℃in resistance on pressure drop resulting from bad to 5v. However, when the temperature is 0 ℃demodulation IC2 potential output allows for OV, the time when 1O0 ℃for IC2 output 5v, in the constant temperature water tank 3 installed AD590, which are located under the sink in the various parts, using its monitoring of temperature changes in the market tank in order to control the stirring motor to ensure uniform temperature sink.1.2 thermostat control circuitConstant temperature control circuit from heating thermostat temperature setting and the composition of the two parts of the circuit. The thermostat circuit settings temperature to provide the working conditions of the heating circuit, the circuit set by the keyboard combination of software programming to achieve common. In addition to each button and set the IO port connected to 8255, but also through a door with the AT89C51 and T0 timer connected so that when the button is depressed immediately after the interruption to the application AT89C51, 8255 inquiry, and at the same time the functions of the corresponding control . One set is the key type from the set and the AT89C51, D / A converter analog voltage measurement is the AD590, after the detection signal AT89C51, D / A converter provides analog, IC3 constitute a comparison amplifier, IC4 ratio amplifier , BG1, BG2, T constitutes a thyristor conduction angle control circuit, a single bipolar transistor oscillator circuit the lower the frequency, SCR's on-the shorter the time the smaller the heating power, on the contrary higher. Single-junction transistors and the oscillation frequency by the ratio of amplifier output voltage control, AT89C51 single-chip temperature settings through the sample and the temperature difference after the value, after amplification by comparison with the temperature change to mediate voltage thyristor the conduction angle in order to achieve the adjustment of heating power to meet the temperature requirements of the waters of the thermostat.1.3 Drive CircuitWhen the 8255 high output corresponding IO port, the drive transistor turn-on 9013, so that the relay action, in order to drive the work of the relevant circuit. Significant choice for a show so that the display to choose between the "settings" and "measurement".1.4 Keyboard control and status indication circuitWith the 8255 connected to the IO port 8 and 9 LED button to complete thecommon waters of the control thermostat and the instructions state. In addition to each button with the 8255 connected to the IO port, but also with AT89C51 it connected the timer so that when the button is depressed immediately after the interruption of AT89C51 applications, and query the status of 8255 in order to carry out the functions of the corresponding control. 1.5 shows the circuit Display circuit using a half the number of table 4 show the temperature head waters of the measurement of temperature and set temperature.2 Software designSkeleton of the software, contains initialization, configuration subroutine, subroutines to deal with temperature, showing subroutine. Completion of system initialization after power-on reset 8255 and software initialization and pre-heated water for the water to wait for work, and open the inlet solenoid valve, when the corresponding button press interrupted when AT89C51, read 8255 the status of the population to determine the function keys in order to call the corresponding subroutine. Subroutine completed one set of the set temperature function. Initialization settings for the "0o.0o", when the choice set and to identify key addition and subtraction operations for each click on the Settings button software settings for the corresponding temperature of the addition and subtraction operation count, and the value storage and display. Subroutine to deal with the role of temperature is the temperature set values and the difference to the SCR trigger circuit heating thermostat control.2.1 The use of Pro / E to establish mold standard parts library FamilyPro/E is part of the family table (or assembly, or the characteristics of) a collection of these parts (or assembly or characteristics) are broadly similar, but in 12 some small differences, for example, fastening screws Hexagon many kinds of specifications, but they seem to be like and to implement the same function, so in the Pro / E in them as a part family is a very useful table in the family the same as a table-driven components parts to be identified. In Pro / E use group table has the following advantages:1) simple and compact to create and store a large number of objects.2) For the generation of standard parts to save a great deal of time and work.3) parts from a series of documents to generate change, do not have to re-create and generate for each part.4) In the parts to create tiny changes in the relationship do not have to use to changethe model.Table feature allows three-dimensional mold standard parts library and standard library mold the development and use of things become very easy. The following guide to commonly used as an example to create a lead-chu-chu series of standard parts. First, Pro / E in the completion of the three-dimensional modeling guide column, and the need to change the size parameters defined as symbols. To mark the size of symbol table for the family members did not indicate the size of the features of a non-changing, dependent on the existence of other features.Family Table is essentially constituted by the rows and columns of the table to start, you can use the Pro / TABLE to create and modify. Here contains examples and their appropriate values, the use of specific projects were listed. Generic model is not in the group table of the project be included in each instance will be automatically generated in accordance with design intent, Family Table, regardless of the merits of another to create a new table or modify an existing table, you can add to the table project. The use of the above-mentioned methods. Enterprises can die design in accordance with the need to build their own three-dimensional mold standard parts library.2.2 The use of Pro / E to establish the standard mold base libraryIn the use of Pro / E to establish the mold standard parts library, in order to further improve the efficiency of die design, quality and standardization, it is necessary to consider the establishment of standard mold base library, the following discussion of how to use Pro / E to establish the standard mold base. The establishment of standard mold base the first thing to consider is the business of processing capacity punching equipment, punching equipment to the processing capacity as well as equipment based on the work table to consider the standard form of mold, practicality and versatility will be higher. In the three-dimensional mold standard parts library has been established under the premise of the establishment of standards mold-base much to the convenience and quick. First of all, to enter the Pro / ASSMBLY equipped) mode, with the establishment of similar communities standard parts, the specific path for the operation: ASSMBLY (components) -- Family Tab (Family Table add-item (additional items)) -- Component (component), and then choose to change to take place in the assembly of parts or components as the assembly of the project group table, and in the assembly do not need to change family (such as fasteners) you do not need to select. instances in the assembly of the assemblyaccording to the agreed relationship between the automatically generated . other aircraft such as the bending modulus, tensile modulus planes.Taking full account of this, pressing equipment and typical performance parameters under the premise of stamping parts, you can use the same solution to create a standard mold base.3 ConclusionAt present, some colleges and universities as a result of provincial funding in the strained devices, laboratory equipment, more backward, in chemistry and chemical engineering laboratories still use a contact thermometer to control water temperature. In order to overcome the factors that a lot of inconvenience to the original based on the old thermostat has been designed transformation of waters. Proved by the use of the design，to meet the current chemistry, chemical engineering and research needs of the experimental results.AT89C51单片机控制的恒温水域温控系统针对化工早期接点温度计恒温水域控温存在的缺点，本文介绍了一种基于AT89C51单片机为主控制器，结合AD590J集成温度传感器等组成的恒温水域温控系统。
