CN203672963U - Digital voltmeter based on singlechip - Google Patents

Abstract

The utility model discloses a digital voltmeter based on a singlechip. An AT89C52 singlechip is adopted, and functions of a simple digital-type DC voltmeter are realized by an A/D converter through an ADC0804 chip. The design of the digital voltmeter is based on single-chip microcomputer minimum system development boards, the AT89C52 singlechip is adopted for controlling, the ADC0804 chip is adopted for A/D conversion, an analog signals is sampled, a digital value is output for being used by the singlechip, and the amplitude of the analog signal is processed and output. According to the design of the digital voltmeter provided by the utility model, the digital value generated through analog-digital conversion by the ADC0804 chip is sent to the singlechip through a transmission line, calculation of the digital value is completed by programs of the singlechip, the digital value is converted into the amplitude of the voltage, and the amplitude of the tested real voltage is displayed on Nixie tubes by controlling display of the Nixie tubes. An LM7805 integrated package is adopted in a power supply module, so as to realize conversion into stable DC 5V voltage, the power supply module is internally provided with current limiting protection, overheating protection and overvoltage protection circuits, a reference voltage source which is low in noise and small in temperature drift is adopted, and thus the operation is stable and reliable.

Description

A kind of SCM Based digital voltmeter

Technical field

The utility model relates to voltage instrument, instrument field, in particular, relates to a kind of digital voltmeter.

Background technology

Being applied at present the voltage table in measuring voltage instrument, instrument, is mainly pointer, with magneto-electric reometer as indicator, and on reometer dial plate with voltage calibration.Pointer-type scale function of voltmeter is single, and precision is low, easily causes parallax and visual fatigue, thereby can not meet the needs of digital times.

For the current situation of current digital voltmeter, adapt to the development trend of electronical display science and technology, specifically high performance in the urgent need to one, stability is high, the digital voltmeter that cost performance is high.

Utility model content

The technical matters that the utility model mainly solves is, for the digital voltmeter of prior art, designs one by monolithic processor controlled, has the digital voltmeter of high impedance, high anti-jamming capacity, high measurement accuracy, high range.

For achieving the above object, the utility model is taked following technical proposals:

A kind of SCM Based digital voltmeter, comprises power module, serial communication, A/D modular converter, main control module, display module;

Described power module adopts LM7805 integrated package, and current-limiting protection circuit, overheating protection circuit and overvoltage crowbar are contained in inside;

Described A/D modular converter, adopts ADC0804 conversion chip, has the A/D converter of 8 road analog inputs, 8 bit digital quantity output functions,

Described main control module, adopt AT89C52 single-chip microcomputer, the analog quantity voltage of ADC0804 chip sampling input port VIN input 0～5 V, after analog to digital conversion, produce corresponding digital quantity sends AT89C52 chip to P1 mouth through its output channel DB0～DB7, AT89C52 is responsible for the digital quantity receiving through data processing, produce the display segment code of 7 segment numeral pipes, and by P0 and P2 mouth through triode, send again charactron to, it also produces position by its four I/O mouth P2.4, P2.5, P2.6, P2.7 and selects signal simultaneously, controls the light on and off of charactron;

The P3.1 pin of AT89C52 connects button, a termination low level of button, and one end is connected to high level by the resistance of 10K, in the time that button is pressed, Low level effective, P3.1 pin is low level, single-chip microcomputer is started working; In the time that button disconnects, P3.1 pin is high level, and single-chip microcomputer quits work.

SCM Based digital voltmeter of the present utility model, adopts AT89C52 single-chip microcomputer, and A/D converter adopts ADC0804 to realize the function of simple and easy digital direct current voltage table.The design of digital voltmeter is based on single-chip minimum system development board, with the control of AT89C52 chip microcontroller, adopt ADC0804 chip to carry out A/D conversion, to analog signal sampling, and export digital quantity and use and process for single-chip microcomputer the amplitude of outputting analog signal.The design first realizes the digital quantity of the analog to digital conversion generation of ADC0804 chip and gives single-chip microcomputer by output line, realized again the computing of digital quantity by Single Chip Microcomputer (SCM) program, convert the amplitude of voltage to, by the demonstration of controlling charactron, on charactron, show the amplitude of our measured virtual voltage.

Power module adopts LM7805 integrated package, can convert stable direct current 5V voltage to realize, and current-limiting protection, overheating protection and overvoltage crowbar are contained in its inside, have adopted the reference voltage source that noise is low, temperature drift is little, and working stability is reliable.1 pin is input end, and 2 pin are earth terminal, and 3 pin are output terminal, uses very conveniently, can use in any place that has an alternating voltage, does not need another charged pool.By output dc voltage after rectifying and wave-filtering, guarantee that whole circuit can normally work.

Brief description of the drawings

Fig. 1 is circuit structure diagram of the present utility model.

Fig. 2 is the power supply diagram of the utility model circuit.

Embodiment

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Figure 1, 2, a kind of SCM Based digital voltmeter, the analog quantity voltage of 0～5 V of ADC0804 chip sampling input port VIN (+) input, after analog to digital conversion, produces corresponding digital quantity and sends to through its output channel DB0～DB7 the P1 mouth of AT89C52 chip.AT89C52 is responsible for the digital quantity that receives, through a data processing, producing the display segment code of 7 correct segment numeral pipes, and by P0 and P2 mouth through triode, then send charactron to; Produce position by its four I/O mouth P2.4, P2.5, P2.6, P2.7 simultaneously and select signal, control the light on and off of charactron.In addition, AT89C52 is also controlling the work of ADC0804, and P3.7 controls the external read data control signal of ADC0804; P3.6 controls the outside of ADC0804 and writes data controlling signal; P3.0 controls conversion beginning and the end signal of ADC0804.

A/D converter is a link in analog input channel, and single-chip microcomputer becomes input analog amount into digital quantity by A/D converter to be processed again.The design is by completing change-over circuit with ADC0804, wherein VCC=5V, and pin VREF/2 is unsettled, the value that the reference voltage that therefore ADC changes is VCC, i.e. 5V.VIN (-) ground connection, and the input of VIN (+) connecting analog magnitude of voltage, therefore the input voltage range of VIN+ is 0V～5V, just in time in reference voltage range.Pin CS, WR and RD are connected respectively the P3.0 of single-chip microcomputer, P3.6 and P3.7 pin, and DB0 ~ DB7 connects the P1 pin of single-chip microcomputer.

Circuit carrys out beginning and the end of control circuit by button, be keying circuit, and concrete principle is as follows, is connected to the P3.1 pin of single chip computer AT 89C52 by button, a termination low level of button, and one end is connected to high level by the resistance of 10K.According to the requirement of design, in the time that button is pressed, Low level effective, P3.1 is low level, single-chip microcomputer is started working; When button disconnects be, P3.1 is high level, and single-chip microcomputer quits work.With this, control the work of whole Circuits System by keying, simple to operate, be easy to the realization of whole function.

Claims (1)

1. a SCM Based digital voltmeter, is characterized in that, comprises power module, serial communication, A/D modular converter, main control module, display module;

Described power module adopts LM7805 integrated package, and current-limiting protection circuit, overheating protection circuit and overvoltage crowbar are contained in inside;

Described A/D modular converter, adopts ADC0804 conversion chip, has the A/D converter of 8 road analog inputs, 8 bit digital quantity output functions,

Described main control module, adopt AT89C52 single-chip microcomputer, the analog quantity voltage of ADC0804 chip sampling input port VIN input 0～5 V, after analog to digital conversion, produce corresponding digital quantity sends AT89C52 chip to P1 mouth through its output channel DB0～DB7, AT89C52 is responsible for the digital quantity receiving through data processing, produce the display segment code of 7 segment numeral pipes, and by P0 and P2 mouth through triode, send again charactron to, produce position by its four I/O mouth P2.4, P2.5, P2.6, P2.7 simultaneously and select signal, control the light on and off of charactron;

The P3.1 pin of AT89C52 connects button, a termination low level of button, and one end is connected to high level by the resistance of 10K, in the time that button is pressed, Low level effective, P3.1 pin is low level, single-chip microcomputer is started working; In the time that button disconnects, P3.1 pin is high level, and single-chip microcomputer quits work.

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