CN102135444A - Portable power mechanical-vibration measurement analyzer - Google Patents

Abstract

The invention provides a portable dynamic mechanical vibration measurement analyzer, the hardware structure of which is as follows: 12 groups of vibration acceleration sensors and 12 groups of constant current source modules are connected in series and connected in parallel to the input end of the A/D conversion module, and the output Terminated to a digital signal processor. The digital signal processor is connected in parallel with modules such as a clock module, read-only memory, random access memory, power-down protection memory, USB interface, battery power supply, control panel keyboard, and control panel LCD screen. The rotational speed counter is connected with the rotational speed sensor in series and connected to the digital signal processor. The software module composed of 6 subroutines including parameter setting, measurement control, data access display, vibration intensity calculation, vibration harmonic analysis and test report generation is stored in the read-only memory. The invention has a built-in vibration measurement and analysis software module, which can independently complete the calculation of the vibration intensity of the power machine and the analysis of the vibration harmonic order without the cooperation of a computer. The instrument is powered by a lithium battery and is suitable for on-site measurement.

Description

Portable Power Machinery Vibration Measurement Analyzer

technical field

The invention belongs to measuring instruments, in particular to a detection device for measuring and analyzing dynamic mechanical vibration.

Background technique

In all fields involving power machinery, the vibration caused by mechanical movement can reduce the reliability of the system, shorten the life of the structure, and some even cause safety accidents. For this reason, it is necessary to measure and analyze these vibrations. In order to evaluate the vibration of power machinery, it is generally necessary to use vibration measuring instruments for testing. In order to find the root of the vibration, it is also necessary to analyze the vibration harmonics of the power machinery. Most of the current power machinery vibration measurements use general-purpose vibration and noise measuring instruments. The structure and working principle of such instruments are basically the same, and they are all composed of sensors, signal conditioners, A/D conversion, spectrum analysis software, and computers. The general-purpose vibration and noise measurement instruments currently used mainly have the following problems: (1) Because the instrument structure is relatively complicated to meet various vibration and noise measurement requirements, the price is expensive; (2) When using this type of instrument, many measurement parameters need to be set. The data processing workload after completion is very heavy, and it is difficult for ordinary technicians to master; (3) The general-purpose vibration and noise measuring instrument needs to be connected to a computer and an external power supply, which is suitable for laboratory measurement and not suitable for on-site measurement without power supply conditions. In addition to general-purpose vibration and noise measurement instruments, traditional portable vibrometers can also be used for simple vibration tests, but this type of portable vibrometer does not have a speed measurement channel, and does not have the analysis functions required for power machinery vibration measurement.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a low-cost portable vibration measurement device that can be used in a site without power supply, has a rotational speed measurement channel, and an analysis function.

The technical principle of the present invention is described below in conjunction with accompanying drawing: the portable power machinery vibration measurement analyzer has: vibration acceleration sensor, constant current source module, A/D conversion module, speed sensor, speed counter, digital signal processor, clock module, It is composed of read-only memory, random access memory, power-down protection memory, USB interface module, battery power supply module, control keyboard, LCD screen of control panel and software module. The software module consists of 6 subroutines including parameter setting, measurement control, data access display, vibration intensity calculation, vibration harmonic analysis and test report generation (as shown in Figure 1). The vibration acceleration sensor has a preamplifier to convert the vibration signal into an electrical signal. The constant current source module supplies constant current to the vibration acceleration sensor and transmits the vibration signal output by the vibration acceleration sensor to the A/D conversion module. The A/D conversion module includes signal conditioner, programmable gain amplifier, analog Σ-Δ modulator, sampler and I/O, etc., which converts the vibration signal into a digital signal and inputs the digital signal through the I/O port processor. The rotational speed sensor is installed on the rotating shaft of the power machine, and synchronously transmits the pulse signal generated by the rotating shaft to the rotational speed counter, and the rotational speed counter measures its rotational speed. The acquisition of the vibration acceleration signal and the rotation speed signal by the A/D conversion module is controlled by a digital signal processor. The clock module provides the clock signal, the read-only memory stores the system program, the random access memory is used for temporary storage of data, the power-failure protection memory stores the measurement data in the form of files, the USB interface module is used for backing up the measurement data and is connected to an external computer, and the battery-powered module controls the lithium battery. The battery supplies power to the instrument, the control panel keyboard is used to input setting parameters and man-machine dialogue, and the control panel LCD module is used to display data.

The characteristics and beneficial effects of the present invention are: compared with the general-purpose vibration and noise measuring instrument, the portable power machinery vibration measurement analyzer only retains the functions necessary for power machinery vibration measurement, which reduces the hardware cost; The parameters are pre-set for the purpose of use, which reduces the complexity of instrument use. Compared with the traditional portable vibrometer, the speed channel is added, and the measurement and analysis software module is embedded, which can independently complete the vibration intensity measurement and vibration harmonic analysis of power machinery without the cooperation of a computer. The instrument is powered by a lithium battery, which is especially suitable for on-site measurements without power supply conditions.

Description of drawings

Figure 1 is a schematic diagram of the hardware structure of the present invention.

Fig. 2 is a flow chart of the software module program of the present invention.

Fig. 3 is a scheme diagram of an embodiment of the present invention.

Detailed ways

The principle structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. Portable power machinery vibration measurement analyzer, its hardware structure is: 12 groups of vibration acceleration sensors 1-1, 1-2, ... 1-12 and 12 groups of constant current source modules 2-1, 2-2, ... 2-12 are all connected in parallel to the A/D conversion module 3 after being connected in series, and the output of the A/D conversion module 3 is connected to the digital signal processor 6 . The digital signal processor 6 is connected in parallel with a clock module 7 , a read-only memory 8 , a random access memory 9 , a power-down protection memory 10 , a USB interface module 11 , a battery-powered module 12 , a control panel keyboard 13 , and a control panel LCD module 14 . The rotational speed counter 5 is connected in series with the rotational speed sensor 4 and then connected to the digital signal processor 6 . The software module 15 composed of six subroutines including parameter setting, measurement control, data access display, vibration intensity calculation, vibration harmonic analysis and test report generation is stored in the read-only memory 8 . Vibration acceleration sensor 1 adopts ICP sensor with built-in integrated circuit; constant current source module 2 provides 24V, 10mA constant current power supply; speed sensor 4 adopts photoelectric speed sensor; counter 5 adopts 16-bit programmable timer/counter; digital signal processing The device 6 adopts a special floating-point format DSP module with a main frequency of 100M or more; the clock module 7 adopts a clock chip with a built-in lithium battery; Digital memory card; USB interface module 11 adopts an interface chip with USB protocol internally encapsulated; battery power supply module 12 adopts a dual-output low-dropout regulator module;

The implementation of the embedded software module of the portable power machinery vibration measurement analyzer is carried out with reference to Figure 2. The software module 15 is composed of six subroutines including parameter setting, measurement control, data access display, vibration intensity calculation, vibration harmonic analysis and test report generation. , Write programs in C language. When running, the mechanical vibration measurement analyzer executes the parameter setting subroutine, and automatically transfers the data saved before the last shutdown, including sensor sensitivity, gain, sampling frequency, sampling time, automatic gain time, LCD screen brightness, and LCD screen contrast. parameters. Users can modify these settings. According to the requirements of power machinery vibration measurement, the default sampling frequency is 2560Hz and the default automatic gain. The gain is automatically set according to the vibration data and peak factor within 5 seconds before measurement to avoid overload due to improper range setting. After the user confirms to start the measurement, start to execute the measurement control subroutine, collect the data of 12 vibration acceleration sensors and the rotation speed data of the rotation speed sensor 4, then call the data access display subroutine, and display the collected data on the control panel LCD module in real time 14. At the same time, it is stored in the power-failure protection memory 10 in the form of a file. Complete one measurement here, and so on until all measurements are completed. Then start the analysis. The data access and display subroutine is transferred to the stored measurement files, and the vibration intensity calculation subroutine is used to calculate the vibration intensity. At the same time, the vibration harmonic analysis subroutine calculates the vibration of each harmonic. Finally, the test report generation subroutine writes the calculation and analysis results into the report file, and so on until all the measurement files are processed. The instrument can be connected to a computer through the USB port to back up measurement data and test reports.

Embodiment: Carry out on-the-spot vibration measurement (as shown in Figure 3) to a certain four-cylinder diesel engine. In this embodiment, 12 groups of vibration acceleration sensors and 12 groups of constant current source modules are used. The first to third vibration acceleration sensors are one group, the fourth to sixth are one group, the seventh to ninth are one group, the tenth to twelfth are one group, and the four groups are respectively installed on the top A of the diesel engine 16 Point, point B in the middle and points C and D where the suspension is installed. Three acceleration sensors in each group respectively measure vibrations in three directions of x, y, and z axes at corresponding points, and the rotational speed sensor 4 is installed on the crankshaft 17 of the diesel engine to measure the rotational speed.

The purpose of the test is to find the source of the vibration increase by measuring the vibration of the engine at different speeds, comparing the values of each harmonic vibration, and analyzing the relationship between the vibration of the diesel engine and its 1st and 2nd reciprocating inertia forces and moments of inertia. Therefore, it is necessary to measure the speed of the diesel engine and the vibration of the diesel engine at different speeds, and perform harmonic analysis on the measured vibration data.

After starting up, the user enters the sensitivity of each acceleration sensor, the instrument automatically sets the sampling frequency to 2560Hz, automatic gain, the automatic gain time is 5 seconds, and the sampling time is 30 seconds, then the instrument enters the state of waiting for user instructions. After the state of the diesel engine meets the requirements of the measurement working conditions, the measurement starts. After 30 seconds, the measurement of the working condition ends. Change the working condition of the diesel engine and start to measure the next working condition. Repeat this until all the working conditions are measured. Then start the analysis, select the measurement file just completed, calculate the vibration magnitude of each point of the diesel engine, the vibration intensity of the whole machine under each working condition, and the vibration harmonic analysis results, and display them on the LCD module of the control panel, and the user can judge accordingly Vibration of diesel engine.

Claims (2)

1. portable power mechanical vibration Measurement and analysis instrument; has vibration acceleration sensor (1); constant current source module (2); A/D modular converter (3); speed probe (4); spin counter (5); digital signal processor (6); clock module (7); ROM (read-only memory) (8); random access memory (9); power down protection storer (10); usb interface module (11); powered battery module (12); supervisory keyboard (13) and control panel liquid crystal display (14) are formed; it is characterized in that N group vibration acceleration sensor (1-1; 1-2; 1-n) with N group constant current source module (2-1; 2-2; 2-n) all be connected in A/D modular converter (3) after the serial connection mutually; the output of A/D modular converter (3) is connected to digital signal processor (6); digital signal processor (6) also is connected with clock module (7); ROM (read-only memory) (8); random access memory (8) (9); power down protection storer (10); usb interface module (11); powered battery module (12); control panel keyboard (13); control panel liquid crystal display module (14); spin counter (5) serial connection speed probe (4) back incoming digital signal processor (6) is by the parameter setting; measure control; data access shows; vibration severity calculates; the software module (15) of vibrating humorous analysis and 6 sub-programs compositions of test report generation is stored in the ROM (read-only memory) (8).

2. according to the described portable power mechanical vibration of claim 1 Measurement and analysis instrument, it is characterized in that described vibration acceleration sensor (1) adopts the ICP type sensor of band built-in integrated circuit; Described constant current source module (2) provides the constant current power supply of 24V, 10mA; Described speed probe (4) adopts photoelectric sensor; Described counter (5) adopts 16 programmable Timer/counters; Described digital signal processor (6) adopts the above special-purpose floating-point format DSP module of dominant frequency 100M; Described clock module (7) adopts the clock chip of built-in lithium battery; Described ROM (read-only memory) (8) adopts the parallel port flash memory; Described random access memory (9) adopts the RAM of 32K digital data; Described power down protection storer (9) (10) adopts the numeric type storage card; Described usb interface module (11) adopts the inner interface chip that has encapsulated usb protocol; Described powered battery module (12) adopts the low pressure reduction Voltage stabilizing module of two-way output; Described control panel liquid crystal display module (14) adopts the liquid crystal display module of monochrome graphics dot matrix.

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