CN201457088U

CN201457088U - Digital automobile meter automatically calibrated by analog signal sampling

Info

Publication number: CN201457088U
Application number: CN2009200940609U
Authority: CN
Inventors: 阮少范; 宋连彬; 邱淑贤; 陈晓春
Original assignee: Siping Huiyu Instrument & Electrical Co Ltd
Current assignee: Siping Huiyu Instrument & Electrical Co Ltd
Priority date: 2009-07-23
Filing date: 2009-07-23
Publication date: 2010-05-12
Anticipated expiration: 2019-07-23

Abstract

The utility model relates to a digital automobile meter automatically calibrated by analog signal sampling, which comprises an analog signal sampling control circuit I, a power circuit II, a switch alarm circuit III, meter drive circuit IV, a digital and switch signal sampling circuit V and a meter control chip, wherein the analog signal sampling control circuit I comprises a sampling electronic switch, one way of the electronic switch is connected with a sampling reference voltage control module, one way thereof is connected with a sampling voltage module, and the another way thereof is connected with the sampling switch control port of the meter control chip. The utility model aims at the possible influence of voltage difference between the analog sensor signal sampling circuit grounding of the digital automobile meter and the meter grounding to adopt the control method and circuit of control measures so as to eliminate the voltage influence that possibly exists in the sensor circuit.

Description

The digital automobile instrument of analog signal automatic sampling correction

Technical field

The utility model relates to a kind of digital automobile instrument, a kind of specifically digital automobile instrument of analog signal automatic sampling correction.

Background technology

At present, the cooling water temperature of auto meter, amount of fuel, the signal input of sensors such as engine oil pressure is input as the master with analog signal basically, in the digital automobile instrument, mainly be to realize the parameter of each analog signal state is changed sampling by the size of measuring the respective sensor voltage signal to this type of Signal Processing, this class onboard sensor signal generally is with in the present pull up circuit of the form body of current signal, in the MCU of auto meter preposing signal process circuit, be translated into voltage signal earlier, and control its input voltage signal in the 0-5V scope by suitable mode, input to the A/D conversion input end of auto meter MCU then through the Filtering Processing of necessity, utilize in-to-in A/D conversion under software control, to finish and measure and drive to show.

Because the sampled voltage signal of analog signal sensors is subjected to all kinds of disturbing influences, can produce certain variation, disturb for some ccasuals in the circuit, can resist by suitable hardware handles, but because the pressure reduction between the instrument that causes behind some electrical work in circuit ground and the sensor ground, can influence the accuracy of analog signal sensors sampled voltage, and then cause the information of instrument demonstration and the information of existing condition to produce difference, can provide wrong information to driver and crew when serious, cause unnecessary driving risk to occur.

The utility model design mainly is at above issuable voltage of system disturbing influence, and the specific aim design measure of taking, promptly by in the analog signal sensors sample circuit, increasing an electronic switch, and conducting and shutoff by auto meter MCU port controlling electronic switch, with every 100ms as a sampling period, control each cycle conducting electronic switch 10ms, 90ms turn-offs, the A/D sampling is sampled twice to each analog signal sensors at the electronic switch on off mode, when being the electronic switch unlatching, once sampling, measure the sample voltage value of analog signal sensors, before electronic switch is opened, measure once again, record the instrument ground that may occur and the voltage difference between the sensor ground.Utilize the value that measures for twice to calculate, obtain the sample voltage value of real simulated signal transducer, as the input value of the sampled voltage of current time analog signal sensors,, control corresponding analog signal instrument and show by calculating and the processing of auto meter MCU.

Summary of the invention

Problem to be solved in the utility model is by take the control method and the circuit of measure of control at issuable voltage difference influence between digital automobile instrument analog sensor signal sample circuit ground connection and the instrumentation grounding, reaching the purpose of eliminating the voltage influence that may exist in the sensor line, thereby provide a kind of digital automobile instrument of analog signal automatic sampling correction.

The purpose of this utility model is achieved in that the digital automobile instrument of this analog signal automatic sampling correction comprises analog signal controlling of sampling circuit I, power circuit II, switch warning circuit III, instrument drive circuit I V, numeral and on-off signal sample circuit V, gauge control chip 3.

Described analog signal controlling of sampling circuit I comprises sampling reference voltage control module, sampled voltage module, has the gauge control chip of sampled voltage control port and sampled voltage input port, it is characterized in that: it also comprises a sampling electronic switch, described sampling electronic switch one tunnel connects sampling reference voltage control module, one the tunnel connects the sampled voltage module, and another road connects the sampling switch control port of gauge control chip.

The utility model is owing to the circuit that adopts said structure and method has the following advantages and good effect:

1, the technical solution of the utility model is the environment for use at present onboard instruments analog signal sensors, taken into full account different vehicle mounted electrical apparatus and may in the voltage sample treatment circuit that generally adopts at present, increase electronic switch control circuit the influence of sensor circuit.With respect to the conventional method of the sampling of present analog sensor signal (promptly phase in once sampling) weekly, the technical solution of the utility model is that the setting sampling period is 100ms, and be controlled in each sampling period by instrument MCU, the analog signal sensors voltage sampling circuit is opened 10ms, turn-offs 90ms.In circuit is opened the interval, measure the value of one-off pattern analog signal sampled voltage, result of a measurement is stored in the specific memory zone; In circuit turn-offs the interval, measure one-off pattern analog signal sample voltage value again, the result is stored in the specific memory zone.Control by auto meter MCU, the result of double sampling is carried out mathematical computations, and, can eliminate the voltage difference that exists between sensor line ground and the instrument ground so reliably to showing the influence of accuracy as a result with the input value of result calculated as analog signal sensors.

2, the utility model adopts the unlatching and the shutoff of electronic switch control analog signal sensors voltage sampling circuit, on the basis that guarantees sensor voltage sampling function, by to being present in the voltage influence double sampling of sensor circuit, can eliminate the influence of the voltage disturbance that sensor circuit may exist, improved the precision of sensor sample, simultaneously, turn-on and turn-off control by switch, also can reduce the energy of analog signal sensors circuitry consumes greatly, only need the value of choose reasonable sampling matched resistance R, the accurate controlling of sampling that just can adapt to different vehicle-mounted analog signal sensors shows for driver and crew provide dynamic on-vehicle information accurately and timely.

3, the utility model method has promptly guaranteed the accuracy of sampled signal, also can reduce simultaneously the power consumption of sensor circuit, improved the adaptedness of instrument product to the vehicle-mounted state of difference, improved the precision of instrument analog signal indication, this controlling models efficiently solves voltage difference between analog signal sensors ground and the instrument ground to the influence of instrument display precision.

Description of drawings

Fig. 1 is the digital automobile instrument integral structure block scheme of analog signal automatic sampling correction.

Fig. 2 is the utility model analog signal controlling of sampling circuit logic block scheme.

Fig. 3 is the utility model analog signal controlling of sampling schematic circuit diagram.

The specific embodiment

Shown in accompanying drawing 1, the digital automobile instrument of this analog signal automatic sampling correction comprises analog signal controlling of sampling circuit I, power circuit II, switch warning circuit III, instrument drive circuit I V, numeral and on-off signal sample circuit V, gauge control chip 3.

Shown in accompanying drawing 2, this analog signal controlling of sampling circuit I comprises sampling reference voltage control module 1, sampled voltage module 2, the gauge control chip (MCU) 3 that has sampling switch control port 5 and sampled voltage input port (A/D) 6, sampling electronic switch 4, described sampling electronic switch 4 one tunnel connects sampling reference voltage control module 1, one the tunnel connects sampled voltage module 2, and another road connects the sampling switch control port 5 of gauge control chip (MCU) 3.

Described sampling electronic switch 4 adopts field effect transistor MOSFET-P; Sampling matched resistance R1 on sampling reference voltage control module 1 suitably selects its value at different analog signal sensors, and the sampled voltage of adjustable mould preparation analog signal sensor is controlled between the 0-5V reliably.

The concrete steps of described digital automobile instrument analog signal automatic sampling correction control method are as follows:

1., by the sampling switch control port 5 of auto meter control chip (MCU) 3, control field effect transistor MOSTFET-P conducting 10ms in the sampling period, sampled voltage input port (A/D) 6 once sampling when shutoff 90ms. is controlled at conducting by auto meter control chip (MCU) 3, the record sampled voltage is to designated memory locations, sampled voltage input port (A/D) 6 once sampling again when turn-offing, the record sampled voltage is to designated memory locations;

2., get above-mentioned 1. double sampling result's voltage difference, input value as actual samples, be after double sampling finishes, calculate the voltage difference of double sampling, and with this input value as the analog signal sensors sampled voltage, after handling by this sample voltage value by gauge control chip (MCU) 3, by the corresponding instrument indication of software program controlling and driving, can dynamically eliminate the influence of the voltage difference that produces between sensor ground and the instrument ground after handling like this to the instrument pointing accuracy, thus guaranteed that instrument is indicated and actual test value between accuracy.

Claims

1. the digital automobile instrument of an analog signal automatic sampling correction, it comprises analog signal controlling of sampling circuit I, power circuit II, switch warning circuit III, instrument drive circuit I V, numeral and on-off signal sample circuit V, gauge control chip (3), it is characterized in that: described analog signal controlling of sampling circuit I comprises a sampling electronic switch (4), described sampling electronic switch (4) a tunnel connects sampling reference voltage control module (1), one the tunnel connects sampled voltage module (2), and another road connects the sampling switch control port (5) of gauge control chip (3).