Multisim2001 software based electronic locks design

Introduction

Electronic circuit design commonly used method is to test design, generally including the design of programmes, programme validation, programme modification 3 phases.

Traditional test design typically manual lap experiment circuit to finish, often need to be tested and modified repeatedly until the correct circuit design. With the electronic and computer technology, produced in computer platforms of EDA (electronic design automation) technology, which in addition to its powerful design features, plus test and simulation analysis, management and other functions. In the EAD desktop design environment "by using your computer to complete the circuit design and simulation of systems integration. Currently used by the EDA software Muhisim, Orcad Pspice, .Ptotel, etc, including computer software known as Muhisim laboratories in the interaction with the interface, and the screen image of intuitive features. 1 Multisim2001 software introduction

Muhisim2001 is Canada IIT (Interactive Image Tech-nologies) company developed specifically for electronic circuit simulation in virtual EWB (Electronic Workbench) software, compared with other software, the software has a large component library, providing approximately 16 000 species _r components and models, especially the large and practical components corresponding to the component model, users can customize the components of the property, you can create your own component library for easy invocation, minimize design mistakes, and enhance the usefulness of the simulation circuit; also has a user-friendly test functions, allowing multiple test instrument (such as distortion meters, spectrum analyzers, network analyzers, etc.) and circuit diagrams together in the same operation interface, conduct tests, allowing components to connect arbitrary, depending on the size of the circuit diagram, the program automatically adjust circuit window size, do not need artificial settings.

The software offers a variety of software emulator, analog circuit, digital circuit, CPLD/FPGA or very complex digital devices (cPu, memory) or complex die a few hybrid circuits, are able to carry out simulation analysis and observe the results.

Multisim2001 software also provides word generator and Logic Analyzer, Logic Analyzer, digital conversion, can solve digital circuits for signal generation, multichannel waveform observation and temporal comparisons, particularly unique virtual instrument, the instrument can implement logic into truth table, logical expressions and logic circuits between mutual conversion, digital circuit design brings great convenience.

Muhisim200l software in the role of digital circuits, particularly conspicuous.

2 electronic locks of composition and theory

2.1 composition of electronic combination lock

Electronic locks with CMOS integrated circuit, unlock and delay-and-hold circuit, the wrong key locking circuit, the main control circuits, debugging control circuits, relay switching circuits, unlock show circuit, etc.

When you enter the password must follow in order to enter and be in a specified time after you have entered, or else, even on the password to open the lock. In addition, the lock also has the wrong key locking and eliminate wrong key features. Electronic locks up the block diagram shown in Figure 1.

　　

　　

2.2 works

There are four passwords of electronic locks of simulation schematic diagram shown in Figure 2.

　　

　　

A) main control circuit: from edge triggered by JK.

JK = 0l, when control-CP appears the rising edge, Q is a low level, so the relay coil, electric snap-action trigger switch action, close the circuit, the LED (light emitting diode) display luminous, the correct password, unlock success.

B) lock and delay-and-hold circuit: set 4 unlock key, provisional order for J1, J2, J3, J4, delay circuits RC circuit, i.e. using RC of charging or discharging to achieve the purpose of delay remains.

While the keys are pressed, the capacitor C4 charging to high level, UlA output low level output, UlB, and keeping housing wait 2 key presses, if J2 on time without pressing the J2, R1, C1 discharge by UlA, Ul B and restored to its original state, and then pressing the J2 will not change the u2A output. If in a specified time, press the J2, u2A output, and maintain for a period of time. Similarly, pressing the J3, J4, ultimately u2C output low level, rising edge through ulE, trigger generated main control circuit unlocking.

C) wrong key locking and debugging control circuit: J5, J6 two wrong key locking switch, that is, when you press both keys in 1 or 2 keys, can make the primary control circuit in blocked State.

Debugging keys J7 is to prevent the master key by mistake which cannot be unlocked after setting, press the mistake when master J5, J6 of 1 or 2 keys, this lock is locked open, only press the debugging keys J7, then in the correct order to enter a password to open the lock.

3 simulation analysis

3.1 electronic locks for simulation of electric schematic diagram design

Simulation of electrical schematics in u1A, u1B, u1C, u1D, ulE, u1F for RP, U2A, U2B, U2E:, enter the second u2D NAND, as normally open relay switching contact.

Enter Muhisim200l working environment interface, may facilitate placing components and instruments: from Basic components in the redeployment of resistors, capacitors, relay, a component from the Sources in the voltage source and grounding symbols, from CMOS components box out and non-, gate, JK, etc., from the Diodes symbol box out LED.

Circuit wiring arrangement in accordance with the circuit diagram of various components, place your mouseThe symbol pin or instrument interface, mouse indicates changes to "+" shape, move the mouse to another symbol pin, that is, complete the connection between the two.

From the component library for various components in the electronic work platforms, display blue components for real components, components for virtual black components, Figure 2 circuit components are choosing real components.

From the library the switch action keys as the space bar, double-click after changing it to other key.

Which password key Jl, J2, J3, J4, respectively, H, O, M, E key, debugging keys to R, the wrong key is set to A, B, CMOS IC's call library power integrated circuits for 10 V.

3.2 electronic locks by process simulation

Press the simulation switch, activate circuit, followed by enter unlock key, that is, H, O, M, E key to relay coil power snap-action contact closure, normal open, the LED is lit.

4 closing

By Muh: isim200l software design locks, as in the laboratory Panel lap circuit, and is not controlled by component type, quantity and test instruments, with its high-quality performance, powerful analysis capabilities and online screen displays allow designers to easily, pleasant, and successfully complete the design task, thus contributing to the design of electronic systems, electronic products and electronic engineering provides a new and convenient way.

Application Multisim200l software can also increase the level of modern educational technologies, improving the experiment environment, integrated design, the ability of the experiment.