BISOPE series 50- Displacement sensor 3 (types and weaknesses)

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Displacement means the maximum distance that has changed around the reference line, so it is easy to intuitively judge the maximum amplitude of vibration, and since the amount can represent and replace the magnitude of stress, the main unit of vibration used in various standards (displacement, speed, acceleration). In particular, it is widely used for direct deflection and vibration of structures, vibration monitoring of pipes, and ‘online monitoring’ of shaft behavior using sleeve bearings. This is also the reason why low-frequency acceleration sensors are widely used. The sensor used at this time is accurate and good for evaluation if it directly outputs the displacement, but on the other hand, there are many cases where its use is limited due to limitations in its installation, orientation, and frequency.

 

​Understanding the diversity and weaknesses of displacement sensors

 

 

Type of Displacement sensor	Image	Disadvantages and Features
Eddy current principle , ​ Proximity probe,  Gap sensor		- Responds only to conductors   - Interference between nearby sensors and nearby conductors (a gap of at least 3 times the diameter of the sensor must be provided)   -Vibration measurement below the unit of mm   Linear measurement below -1000Hz
LVDT		-Linear variable differential transducer (measuring the amount of movement of protrusions, bar type, wire type, )   - When measuring absolute displacement, it is necessary to manufacture a jig for the reference position   - Suitable for low frequencies (below 50Hz)
Strain gauge		Measuring micro displacement, vulnerable to noise
Laser doppler		High-frequency measurements (40 kHz) are very expensive
Ultrasonic		Weak in accuracy, low price, general purpose
CCTV, GPS		Currently actively researching resolution issues

 

 

 

​https://blog.naver.com/vs72

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BISOPE series 7 3 axis vibration sensor 3 axis vibration and accelerati...

BISOPE series 7- 3-axis vibration sensor (3-axis vibration and acceleration sensor)

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An accelerometer is the easiest transducer to measure vibration. Since the measurement direction of this transducer has already been determined, the sensor must be placed in the desired direction for measurement. It doesn't really matter if it's up or down. This is because vibration is repeated and if you want to know the relative movement, you have to use two or more sensors that measure it at the same time anyway. In this case, the concept of a phase is only additionally required. However, compared to a single axis vibration sensor, a triaxial vibration sensor literally means a sensor having the ability to measure the magnitude of vibration in three axes at the same time. It is easy to measure and you will be able to identify vibrations in all directions in a short time.

 

Advantages and disadvantages of Triaxial Accelerometer

Triaxial is described as each three-dimensional orthogonal direction in Z, X, and Y directions (H, V, A directions in the case of vibration diagnosis of rotating equipment) that are perpendicular to each other. The axes in each direction have an initial phase difference of 90 degrees from each other, and the 3-axis vibration acceleration sensor outputs the amount of vibration acceleration in each direction as voltage. Therefore, it can be said that the 3-axis vibration sensor has the following advantages.

 

First of all, it is possible to measure the vibrations in all directions at the same time. It measures the vibration in each axis direction at the same time without the need to measure it sequentially with several different sensors or at different times, so it is possible to prove the simultaneous state at the time and shorten the measurement time.

 

Second, it is possible to measure -----

 

On the other hand, the 3-axis vibration acceleration sensor is at least twice as high expensive as the combined price of all three single-axis sensors, and the average probability of failure (MTBF) of the single-axis sensor is shortened to 1 year compared to the manufacturer's recommended 3 years. do. However, in fact, the piezo-type accelerometer is more robust and less durable than expected, so it is not easy to check the broken state. Recently, like a gyro sensor, a modularized sensor capable of measuring 6-axis vibration has already appeared, and like MEMS, which basically employs 3 axes, new-technology vibration sensors with clear advantages of low frequency have already started to lead in price. The day when MEMS sensors will be used more often than piezos can be seen in the near future.

 

Key! Vibration sensor, accelerometer,, Acceleration, Accelerometer, piezoelectric effect, piezoelectric element,piezo,ICP,3 axis vibration sensor,3 axis vibration, vibration measurement ,mems, iepe, vibration education

 

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