CN202403834U

CN202403834U - Multipoint network distribution type temperature detecting system

Info

Publication number: CN202403834U
Application number: CN201120538485.1U
Authority: CN
Inventors: 熊璞; 张磊; 张永恒
Original assignee: CHENGDU ZONGXUN TECHNOLOGY Co Ltd
Current assignee: CHENGDU ZONGXUN TECHNOLOGY Co Ltd
Priority date: 2011-12-21
Filing date: 2011-12-21
Publication date: 2012-08-29
Anticipated expiration: 2021-12-21

Abstract

The utility model provides a multipoint network distribution type temperature detecting system. The system comprises a single chip computer, a plurality of temperature sensors DS18B20 connected with the single chip computer, a keyboard module, an LCD (liquid crystal display) module and an alarm; the plurality of DS18B20 temperature sensors transmit the collected temperature signal to the single chip computer; the single chip computer processes the signal and displays a result on the LCD (liquid crystal display) module; the keyboard module is used for setting the temperature values measured by corresponding temperature sensors and the alarming temperature. According to the multipoint network distribution type temperature detecting system, the digital temperature sensors DS18B20 are adopted and have a special single bus interface form, namely, tens of and even hundreds of digital sensors are allowed to be hung on one signal line, so that the interface between the temperature measuring device and each sensor is very simple, the defect that a necessary A/D (analogue/digital) converter and other complex circuits are needed when an analogue sensor is connected with an microcomputer interface is overcome.

Description

Multidrop network distributed temperature detection system

Technical field

The utility model relates to electric network monitoring field, and a kind of multidrop network distributed temperature detection system is provided.

Background technology

21 century, science and technology development is maked rapid progress, and the progress of science and technology has driven the development of measuring technique, and earth-shaking variation has taken place for the performance of modern opertaing device and structure.We have got into the information age of high speed development, and measuring technique also becomes a main flow of current science and technology, are deep into the every field of research and application project widely.

Temperature is the physical quantity that and people's living environment have substantial connection, also is a kind of important physical amount that in production, scientific research, life, needs measurement and control, is one of seven fundamental quantities of International System of Units.Variation of temperature brings significant impact can for our life, work, production etc., and is therefore most important to the measurement of temperature.It measures the general temperature sensor that uses form of all kinds of control.Development along with modern computer and automatic technology; The function element of handling mutually as various information perception, collection, conversion, transmission; Show the effect day of temperature sensor outstanding; Become indispensable important technology instrument in automatic detection, automatic control system and the metrology and measurement, it uses the every field that has spreaded all over industrial and agricultural production and daily life.

Distributed temperature sensor has important application prospects at power industry, colliery, forest, fire, skyscraper, Aeronautics and Astronautics aircraft etc., causes researchist's extensive concern.In recent years, the report of many distributed temperature sensors has been arranged, comprised based on the Raman temperature sensor of fiber nonlinear effect etc., but because its expensive cost and can't being widely used.The utility model has used the digital temperature sensor DS18B20 of new generation of American Dallas semiconductor company; It has unique single bus interface mode; Promptly allow on a signal line, to articulate tens of even up to a hundred digital transducers; It is very simple that thereby the interface that makes temperature measuring equipment and each sensor becomes, the A/D converter that has needed when having overcome analog sensor and microcomputer interface and the shortcoming of other complex peripheral circuit.

The utility model content

It is a kind of simple in structure, with low cost that the purpose of the utility model is to provide, the multidrop network distributed temperature detection system of good reliability.

The utility model is for realizing that above-mentioned purpose adopts following technical scheme:

A kind of multidrop network distributed temperature detection system is characterized in that: comprise single-chip microcomputer, a plurality of DS18B20 temperature sensors, Keysheet module, LCD display module and the alarm that are connected with single-chip microcomputer;

Said single-chip microcomputer and LCD display module annexation do, P0.0 meets DB0, P0.1 and meets DB1, P0.2 and meet DB2, P0.3 and meet DB3, P0.4 and meet DB4, P0.5 and meet DB5, P0.6 and meet DB6, P0.7 and meet DB7, P3.7 and meet RS, P3.0 and meet RW, P3.3 and connect that E, P3.5 meet CS1, P3.6 meets CS2;

The DQ pin of said a plurality of DS18B20 temperature sensors is articulated on the bus and is connected with the P1.7 of single-chip microcomputer;

Two four inputs of said Keysheet module are connected with the P3.2 pin of single-chip microcomputer with a 74LS21, and H3 meets P2.7, H2 and meets P2.6, H1 and meet P2.5, H0 and meet P2.4, L3 and meet P2.3, L2 and connect that P2.2, L1 meet P2.1, L0 meets P2.0;

Said alarm drives input end and is connected with single-chip microcomputer P3.4.

The utlity model has following beneficial effect:

The utility model adopts digital temperature sensor DS18B20; It has unique single bus interface mode; Promptly allow on a signal line, to articulate tens of even up to a hundred digital transducers; It is very simple that thereby the interface that makes temperature measuring equipment and each sensor becomes, the A/D converter that has needed when having overcome analog sensor and microcomputer interface and the shortcoming of other complex peripheral circuit.

Description of drawings

Fig. 1 is the system block diagram of the utility model.

Embodiment

DS18B20 is an intelligent temperature sensor, and digital quantity is adopted in its I/O, with Single Wire Bus Technology, receives the order that main frame sends, and handles accordingly according to the agreement of DS18B20 inside, and the temperature of changing is sent to main frame with serial ports.Main frame is according to the sequential of communication protocol with an IO mouth analog D S18B20; Send order (initialization command, ROM order, command function) and give DS18B20; And read temperature value, and carry out relevant numerical in inside and handle, show the temperature of each point with the graphic lcd module.

Each DS18B20 has the sequence number of oneself; Therefore native system can articulate 4 DS18B20 on a bus; Through CRC (CRC) verification, the ROM of each DS18B20 is carried out addressing, the DS18B20 that the address meets just responds; Receive the order of main frame, send the temperature of conversion to main frame.Adopt this DS18B20 addressing technique, make the system hardware circuit simpler.

Keyboard circuit

Although it is different to constitute determinant keyboard version, their principle of work is identical, and existing is that example is explained with Fig. 2: column rule P2.4-P2.7 is output, and alignment P2.0-P2.3 is input.CPU makes first row (P2.4) be " 0 ", all the other behaviors " 1 " earlier.Read the state of input port P2.0-P2.3 then, if the state of input buffer all is " 1 ", no key that then expression is expert at is pressed; Next CPU makes a downlink be " 0 "; All the other column rules are " 1 ", and the scanning next line carries out in the P2.4-P2.7 circulation like this.If input buffer be not " 1 " entirely, explain that institute is expert at and has key to press, CPU stops the current line line sweep, is transferred to alignment and scans, and alignment P2.0-P2.3 is that the tabulation of " 0 " state shows that correspondence shows key and press.Like this, column rule and columns cross key are exactly the button that scans.The key scanning mode has three kinds.

One, the reliable input of bond switching state has two kinds of solutions.

A kind of is that software goes shake: it is when having detected key and press; After carrying out the delay procedure of a 10ms; Confirm again whether this key level still is kept closed level, as be kept closed level and then confirm as real key down state, thereby eliminated effect of jitter.Another kind goes shake for hardware: be button and add a latch.Two kinds of methods are all simple, and what the design adopted is that hardware goes to tremble.

Two, to encode given key assignments or provide key number of button

No matter have or not coding for button, and adopt what coding, all to be converted at last with totalizer in the corresponding key assignments of numerical value, move with diffusing the walking around of realizing the keypress function program.For making encoded interval little, loose that it is convenient to change the port address arrangement over to, often adopt key that preface successively arranges number.

Three, select the keyboard monitoring method

The information input mode that whether has key to press there are two kinds of interrupt mode and inquiry modes.The query method that the utility model adopts is promptly calling the keyboard scan subroutine when CPU is idle.

Claims

1. a multidrop network distributed temperature detection system is characterized in that: comprise single-chip microcomputer, a plurality of DS18B20 temperature sensors, Keysheet module, LCD display module and the alarm that are connected with single-chip microcomputer;

Said Keysheet module is connected with the P3.2 pin of single-chip microcomputer;