CN102095896B - Portable intelligent speedometer tester and using method thereof - Google Patents

Abstract

The invention discloses a portable intelligent speedometer tester and a using method thereof, belongs to the technical field of automatic detection, and particularly relates to an intelligent tester for testing a plurality of speedometers of an airplane, a steamship, a train, a car and the like simultaneously. The portable speedometer tester based on a DSP (Digital Signal Processor) is characterized in that the tester can test speedometers to be tested without rotating the speedometers, thus equipments such as various shafts, a speed regulator, a belt driving mechanism, a roller and the like are saved; a plurality of speedometers can be tested automatically and simultaneously, measured values of the speedometers to be tested can be collected in real time, and errors can be recorded and analyzed; the tester can test speedometers used on various rotating machines through real-time maintenance of parameters; and the tester solves the problems that the traditional testing table has narrowapplication range, is inconvenient to carry, has high labor intensity and low working efficiency and the like.

Description

A portable speedometer intelligent tester and its usage method

technical field

The invention relates to a portable speedometer intelligent tester and a method for using the same, belonging to the technical field of automatic detection, and in particular to an intelligent tester capable of simultaneously detecting multiple speedometers such as airplanes, ships, trains and automobiles.

Background technique

The vehicle speedometer is an important instrument to monitor the driving of the vehicle, and its integrity and accuracy are directly related to the driving safety of the vehicle. In order to ensure the driving safety of motor vehicles and avoid road traffic accidents caused by inaccurate speedometers, according to Article 9 of the "Measurement Law of the People's Republic of China" and Article 25 of the "Detailed Implementation Rules for the Measurement Law of the People's Republic of China", the Measuring instruments must be periodically calibrated in accordance with the law, and the longest calibration period shall not exceed one year. Although there are many current studies, they are generally carried out on the test bench, that is, the speedometer to be tested is calibrated on the test bench with the speed indication of the coaxial standard speedometer. The speedometer is removed, the work is complicated and labor-intensive, and there are also problems such as inconvenient to carry, low work efficiency, and low calibration accuracy. For example, the "Intelligent Digital Display Car Speedometer Calibration Bench" introduced by Wu Zhengbin and Yang Xiaosong adopts a double-wheel-double-drum structure, so that the drive axle wheels of the car can be reliably connected with the test bench measuring rollers, so the linear speed of the car wheels is equal to the measurement The linear speed of the drum is used to verify the speedometer. The "LSY-302 Intelligent Locomotive Speedometer and Diesel Engine Tachometer Dual-purpose Calibration Platform" introduced by Tan Cimin is mainly composed of a synchronous belt transmission mechanism, an intelligent standard meter and a thyristor stepless speed regulating device, which are respectively installed in a sheet metal structure. In the control cabinet, several key components of the test bench have been carefully selected in the design. For example, the synchronous belt transmission mechanism is adopted, which greatly simplifies the structure, reduces the self-weight and noise, and uses the thyristor stepless speed regulating device to regulate the speed, which ensures the adjustment width and achieves the purpose of stable adjustment. However, the above-mentioned calibration tables are mainly driven by a synchronous belt transmission mechanism, and the tachometer (or sensor) is installed at the end of the crankshaft, the end of the camshaft or other shaft ends, and an AC speed regulating device must be provided, and the structure is complicated and the cost is high.

The author also introduced a verification device in the article "DesigR for the SYstem of Speedometer TestiRg Set", which was developed with MCS51 single-chip microcomputer and used to verify the speedometer on the electric locomotive. It is for special purposes. It can send out the code pulse of DF16 photoelectric encoder used in electric locomotives, so that the speedometer display can achieve the purpose of verification. The verification device in this article cannot retrieve the actual value of the speedometer, so it cannot give the deviation number, and the scope of application is very limited.

Contents of the invention

The present invention is a portable speedometer intelligent tester and its use method, aiming at the limitations of the above-mentioned disclosed calibration platform, providing a device that can be calibrated without rotating the speedometer to be tested, which saves Various shafts, speed regulating devices, belt transmission mechanisms, rollers and other equipment have been removed, and the automatic calibration of multiple speedometers can be realized at the same time, and the measured values of the speedometers to be tested can be collected in real time to record and monitor their errors. Analysis, through the real-time maintenance of parameters, the verification of various rotating machinery speedometers can be realized, so as to solve the problems of narrow application range, inconvenient portability, high labor intensity and low work efficiency of the existing verification platform. The present invention is based on DSP A technical solution of a portable speedometer tester and a method of use thereof.

A portable speedometer intelligent tester of the present invention is characterized in that it is a portable speedometer tester based on DSP, and the technical scheme adopted by the tester is mainly composed of a microcontroller unit, a communication interface unit, a signal conditioning unit, a keyboard Composed of a display unit and a clock unit, where:

Described microcontroller unit comprises DSPCPU, off-chip RAM, power supply, crystal oscillator circuit, JTAG interface circuit, LCD indicator light and and jumper wire;

The communication interface unit includes an RS-232 drive circuit;

The signal conditioning unit includes a pulse signal input conditioning circuit and a pulse signal output conditioning circuit;

The keyboard display unit includes a keyboard interface circuit and an LCD display circuit;

The clock unit includes a level conversion buffer circuit;

For each module mentioned above, the communication interface unit is connected to the microcontroller through the serial port communication interface module SCI, and the signal conditioning unit, keyboard display unit, and clock unit are connected to the microcontroller through the I/O port;

The off-chip RAM in the above-mentioned microcontroller unit is connected with the DSP through a 16-bit address data bus and a chip select line;

The serial port communication module of the above-mentioned communication interface unit DSP is connected with the host computer through the driver chip MAX3232;

The pulse signal input of the above-mentioned signal conditioning unit is connected to the IO port of the DSP through the isolation buffer circuit, and the pulse signal output from the DSP IO port is sent to the speedometer to be verified after being photoelectrically isolated;

The pulse signal output from the DSP IO port in the above-mentioned signal conditioning unit is sent to the speedometer to be verified after being photoelectrically isolated. The output of the digital signal of the speedometer is connected to the IO port of the DSP through an isolation buffer circuit. The analog signal is conditioned and connected to the ADC of the DSP.

The matrix keyboard terminal line in the above-mentioned keyboard display unit is connected to the IO port of the DSP, and the LCD is connected to the parallel IO of the DSP through a level conversion module;

The above-mentioned clock unit is connected to the IO of the DSP through a level conversion buffer circuit.

The above-mentioned method for using a portable speedometer intelligent tester is characterized in that the implementation steps are as follows:

、设置参数给出各种命令

, set parameters to give various commands

The speedometer receives the photoelectric pulse from the photoelectric speed sensor when the device is running, and connects it to the outer rim when in use, that is, K pulses per revolution, the output waveform is a square wave, and the duty cycle is 50%±2%. , the output amplitude is high level ≥ U _H , low level ≤ U _L , this signal is isolated, and the driving speedometer shows that an output system that can output the same signal instead of the sensor is designed according to the above parameters; through the small keyboard function key to set parameters and give operation commands, including:

Set the wheel diameter, set the number of photoelectric codes sent in one circle, display the wheel diameter, display the speed value, set the speed, check, store the detection data and send it to the host computer.

、校验

,check

For each speedometer, due to the difference in the diameter of the rotating wheel, it must be input into the DSP every time to send out the number of pulses corresponding to the linear speed. Since the information of the test data, deviation and time must be recorded in the off-chip RAM and It is transmitted to the upper computer, so this system has a calendar and clock chip DS12887. By setting the initial value of the calendar and clock, DS12887 automatically starts to record the time and date; after completing the input and adjustment of the above parameters, input a speed value and press the keyboard "Start", the DSP will start to calculate the timing time according to the set parameters, and send pulses to the speedometer with this time as a cycle, the speedometer will display the speed value until the next speed value is entered, and the DSP will repeat the calculation, output and The process of verification; the speed sensor sends K pulses for one revolution of the wheel, and KR pulses for R revolutions. If the diameter of the rotating wheel is D mm, the given speed is R km/h, which is (10 ⁶ R)/(3600) mm/s, that is (10 ⁶ R)/(3600πD) cycle/s, that is (10 ⁶ R)×K/(3600πD) pulse number/s, then the pulse period T=(3600πD) / ( (10 ⁶ R )×K) seconds, since the pulse signal duty ratio of the speedometer is 1/2, the timing time is T/2; the crystal oscillator is 30MHZ, and the timing initial value Y should satisfy: (65535-Y)·12/(30× 10 ⁶ )=(1/2)·(3600πD) / ( (10 ⁶ R)×K), so Y=65535- 4500πD /(R×K), whenever the timing time is up, a timing interrupt will be generated to execute the interrupt In the service program, the output terminal is reversed in the interrupt service program, so that a pulse waveform with a uniform interval between high and low levels is obtained, and the high level of the output voltage is 12V, that is, the voltage value of the isolated power supply, which can be adjusted according to the output amplitude of the speed sensor , the TTL low-level value is 0.3V, which is completely consistent with the output signal of the speed sensor. This signal is connected to the speedometer through the I/O port with photoelectric isolation and the soft connector, so that the speedometer can be displayed. check the table;

、记录查询分析

, record query analysis

Data recording, query, and analysis are partly realized by the upper computer PC. This function is developed on the PowerBuilder11.5 platform using the SQL Server 2008 database. There are modules such as system maintenance, data receiving management, data receiving information supplementary management, and data receiving query. Composition, the real-time data of a plurality of speedometers of the present invention is collected by the I/O mouth of DSP, reads the actual value of speedometer after sending out pulse signal, and records in the off-chip RAM, carries out necessary after being passed on to the upper computer for follow-up. analysis.

The advantages of a portable speedometer intelligent tester and its use method are: due to the improvement of the structure of the calibration platform and the combination of CPU technology, as long as the calibrator is taken on the car and connected to the speedometer with a cable, the Start the test without removing the speedometer, which solves the problems of inconvenient portability, high labor intensity and low work efficiency of the existing calibration table. Compared with the existing calibration table, its main advantages and positive effects are:

(1) The calibration of the speedometer is realized completely by CPU and digital technology, without the need for complex structures such as belt transmission mechanism, crankshaft, camshaft, AC speed control device, etc. The product is more integrated, portable, high in reliability and low in cost. Low, long service life;

(2) It has a wide range of applications, and all parameters can be input in real time, including the diameter of the rotating wheel, the number of photoelectric codes sent per revolution, and the amplitude of photoelectric pulses, so as to adapt to the speedometer calibration of different types and applications;

(3) Powerful functions, capable of calibrating 16 speedometers at the same time;

(4) The system structure is clear, easy to operate, and the calibration results are intuitively displayed;

(5) The verification speed is fast, the degree of automation is high, and the precision is high; the present invention does not calculate the frequency of the signal, but the period of the pulse in terms of the generation of the pulse signal. Since the frequency of the crystal oscillator of the DSP is relatively high, the timing time can be adjusted. to the microsecond level, so the obtained cycle accuracy is high, the resolution of the measurement speed is high, and the measurement range is very wide, which can reach a speed range of tens of thousands of kilometers per hour. The pulse signal is sent to the I/O port through photoelectric isolation. The I/O port can output 16 channels at the same time, and test several speedometers at the same time;

Description of drawings

Fig. 1 is the functional block diagram of the speedometer intelligent calibrator based on DSP of the present invention;

Fig. 2 is a schematic diagram of microcontroller of the present invention;

Fig. 3 is a schematic diagram of the communication interface of the present invention;

Fig. 4 is 16 road pulse signal generation schematic diagrams of the present invention;

Fig. 5 is 16 speedometer output signal acquisition principle diagrams of the present invention;

Fig. 6 is a schematic diagram of the keyboard interface circuit of the present invention;

Fig. 7 is a schematic diagram of the display circuit of the present invention;

Detailed ways

The specific embodiment of the present invention is described in further detail in conjunction with accompanying drawing as follows:

As shown in Figure 1, a kind of DSP-based portable speedometer calibrator of the present invention comprises microcontroller unit, communication interface unit, signal conditioning unit, keyboard display unit, wherein:

Described microcontroller unit, the minimum system of DSP comprises CPU, off-chip RAM, power supply, crystal oscillator circuit, JTAG interface circuit, LCD indicator light and necessary jumper;

The communication interface unit includes an RS-232 drive circuit;

The signal conditioning unit includes a pulse signal input conditioning circuit and a pulse signal output conditioning circuit;

The keyboard display unit includes a keyboard interface circuit and an LCD display circuit;

For the modules mentioned above, the communication interface unit is connected to the microcontroller through the serial communication interface module (SCI), and the signal conditioning unit and the keyboard display unit are connected to the microcontroller through the I/O port.

(选通数据空间)和

（选通程序空间）相与作为RAM的选通线。仿真器通过JTAG仿真接口与DSP连接，以便于调试DSP硬件和软件。电源模块是采用12V的开关电源经过L7805三端稳压器转换成5V直流电。电压转换采用TI公司的5V/3V高性能稳压芯片TPS7333Q将+5V转换成+3.3V供DSP使用，为了保证芯片的稳定工作和提高核心板的抗干扰能力，模数电压和模数地之间分别采用10mH电感和0

电阻进行隔离，在芯片的每个电源输入引脚处都连接了去耦电容。复位电路采用MAXIM公司具有人工复位功能的MAX811芯片，实现对电压的精密监控，提供掉电复位、上电复位及电压跌落复位等多种功能。时钟电路采用晶振方式，由锁相环时钟电路和晶振电路组成，锁相环时钟电路设计了由0.015F、0.68

F电容及11

的电阻组成的PLL滤波电路，晶振选用10M的有源晶振，其4脚接3.3V电压，2脚接地，在3脚接DSP的CLKIR引脚，经DSP内部4倍频即后获得40MHz的系统时钟。 As shown in Figure 2, the microcontroller unit CPU adopts TMS320LF2407 DSP chip of TI Company, expands a 64×16bit RAM, adopts CY7C1021CV33 chip of CYpress Company, it uses 16-bit address data bus, chip selection line, read and write line connected to the DSP, use the

(gated data space) and

(Strobe Program Space) Phase AND acts as a strobe line for RAM. The emulator is connected with DSP through JTAG emulation interface, so as to debug DSP hardware and software. The power module adopts 12V switching power supply and converts it into 5V DC through L7805 three-terminal voltage regulator. The voltage conversion uses TI's 5V/3V high-performance voltage regulator chip TPS7333Q to convert +5V into +3.3V for DSP use. In order to ensure the stable operation of the chip and improve the anti-interference ability of the core board, the analog-to-digital voltage and between 10mH inductor and 0

Resistors are used for isolation, and decoupling capacitors are connected to each power input pin of the chip. The reset circuit adopts the MAX811 chip with manual reset function of MAXIM Company, which realizes precise monitoring of the voltage and provides various functions such as power-down reset, power-on reset and voltage drop reset. The clock circuit adopts the crystal oscillator mode, which is composed of the phase-locked loop clock circuit and the crystal oscillator circuit. The phase-locked loop clock circuit is designed by 0.015 F, 0.68

F capacitance and 11

A PLL filter circuit composed of resistors, the crystal oscillator uses a 10M active crystal oscillator, its 4 pins are connected to 3.3V voltage, 2 pins are grounded, and 3 pins are connected to the CLKIR pin of DSP, and the 40MHz system is obtained after 4 frequency multiplication inside the DSP. clock.

As shown in Figure 3, the SCI communication interface unit adopts the low-consumption drive chip MAX3232 conforming to the RS-232 standard to realize the conversion between TTL level and PC level, and realize the communication between DSP and the host computer through the Modbus protocol.

As shown in Figure 4 and Figure 5, the digital output of the 16-way speedometer in the signal conditioning unit is isolated by the photoelectric TLP521-4, buffered by the SR74LS244R and connected to the IO port of the DSP, and the pulse signal output by the 16-way IO port is passed by the photoelectric TLP521- 4 isolated feeds into 16 speedometers to be calibrated.

As shown in Figure 6 and Figure 7, the keyboard interface circuit in the keyboard display unit is designed with function keys and number keys, such as the number setting of speedometer, speed setting, wheel rim diameter setting, and the number of photoelectric codes sent per revolution. number setting. The keyboard used is a 4×3 12-key keyboard. The function of the shift key is set, that is, the function key and the number key are multiplexed. The 7 pins drawn from the keyboard are connected to the IOPB0-IOPB6 of the DSP respectively. IOPB4~IOPA6 correspond to the 1st~3rd row of the keyboard, IOPB0~IOPB3 correspond to the 1st~4th row of the keyboard, and the 4 pins of the keyboard row are respectively connected to 3.3V through pull-up resistors. The display circuit liquid crystal module adopts CM128640-10SLYB liquid crystal display, which is connected to DSP through read-write line, chip select line, data bus, and the level conversion of TI company is used between DSP data interface (3.3V) and LCD (5V) data interface The device SR74LVC4245DB performs bus level conversion, and uses a 20KΩ sliding rheostat to adjust the contrast of the liquid crystal display.

When in use, at first install the intelligent calibration detector, which can be realized by those in the technical field. The second is the operation method of the intelligent calibration detector.

This system can give the pulse signal required by the speedometer, thus realizing the static detection problem of the speedometer. The system is divided into two parts, that is, the speedometer test part and the data record, query and analysis part.

1. The speedometer verification is realized by DSP, and the parameters can be set through the function keys of the small keyboard, and various operation commands can be given, including:

F1: Set the wheel diameter, input the four-digit value one by one, if it is less than four digits, add 0 in front, and have "CL" logo;

F2: Given speed, input three-digit values one by one, if less than three digits, add 0 in front, press the "Start" button every time you set it, and start to calculate the number of pulses according to the set parameters and speed, and input them through the I/O port give the speedometer;

F3: Set the number of photoelectric codes sent out in one circle, input four-digit values in sequence, if less than four digits, add 0 in front, and have "SL" logo;

F4: Display the wheel diameter, display the four-digit value on the keyboard, and have a "ZJ" logo;

F5: display speed value, display three-digit value on the keyboard, and have "SD" mark;

F6: Send, upload the memory in the integrated board memory RAM to the PC, and clear the RAM at the same time;

2. The data recording, query and analysis are realized by the host computer (PC). This function is developed on the PowerBuilder11.5 platform using SQL Server 2008 database, and consists of modules such as system maintenance, data receiving management, data receiving information supplementary management, and data receiving query.

System maintenance is the entry of personnel and other information in Chinese characters, which provides convenience for future use and ensures the uniqueness of its entry. After entering the data receiving management, first click the "Receive Data" button, and then press the F key on the CPU integrated function board to send, and the receiving screen will appear. " Exit, and then click "Convert Data", the received data will be displayed in the data window below, and finally click "Into General Database", these records will enter the general database, and the content of the data window will disappear at the same time.

Then enter the data receiving information supplement management module to supplement the tester and other information. First enter the start date and end date. After pressing Enter, all records in this date range will be displayed in the data window below. After selecting the tester, all records will be added to this tester. You can also click on each tester Add or modify testers one by one, and also add confirmers or remarks.

The data receiving and query module is designed for querying data information. Click the small box to select this condition, and the selected condition is the relationship of "and". Click "Condition Selected", and the records meeting the conditions will be displayed in the data window below. Click "All Query", all records will be displayed again. And you can also modify the relevant information (confirmer, remarks). After the modification, click "Modification Complete", and the password input window will appear. If the input is correct, the modification will take effect, otherwise it will not take effect.

Claims (1)

1. A portable speedometer intelligent tester is characterized in that it is a kind of portable speedometer tester based on DSP, and this tester comprises microcontroller unit, communication interface unit, signal conditioning unit, keyboard display unit and clock unit, in: Described microcontroller unit comprises DSPCPU, off-chip RAM, power supply, crystal oscillator circuit, JTAG interface circuit, LCD indicator lamp and jumper; The communication interface unit includes an RS-232 drive circuit; The signal conditioning unit includes a pulse signal input conditioning circuit and a pulse signal output conditioning circuit; The keyboard display unit includes a keyboard interface circuit and an LCD display circuit; The clock unit includes a level conversion buffer circuit; Described communication interface unit is connected with DSPCPU by serial port communication interface module SCI in DSP, and described signal conditioning unit, keyboard display unit, clock unit are connected with DSPCPU by I/O port in DSP; The off-chip RAM in the described microcontroller unit is connected with DSP through 16-bit address data bus and chip select line; The serial port communication interface module SCI adopts the low-power driver chip MAX3232 conforming to the RS-232 standard, realizes the conversion between TTL level and PC level, and realizes the communication between the DSP and the upper computer through the Modbus protocol; The pulse signal input of the signal conditioning unit is connected with the I/O port of the DSP through the isolation buffer circuit, and the pulse signal output from the I/O port of the DSP is sent to the speedometer to be verified after being photoelectrically isolated, wherein the speedometer The output of the digital signal is connected to the I/O port of the DSP through the isolation buffer circuit, and the analog signal of the speedometer is connected to the ADC of the DSP after conditioning; The matrix keyboard terminal line in the described keyboard display unit is connected with the I/O port of DSP, and the LCD display circuit is connected with the I/O port of DSP through the level conversion module; The clock unit is connected with the I/O port of the DSP through a level conversion isolation buffer circuit.

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