Everyone

Kröber

Jelly Bean

Acceleration measurement and determination of the relevant frequency, the acceleration and the amplitude of the oscillation 

Explanation of the buttons arranged on top of the screen

CONTI: Continuous measurement

5 SEC: Fixed measurement duration of 5 sec, then STOP automatically

STOP: Stop of measurement, the last 5 seconds are displayed

-: In stop mode, move zoom window (1.28sec) to the left, only for PRO version

+: In stop mode, move zoom window (1.28sec) to the right, only for PRO version

There are seven figures below the buttons.

Upper figure "Current acceleration values":

The accelerations values are displayed. The sampling frequency of most smartphones is 50 Hz. If the actual sampling frequency deviates by ± 1 Hz, then the actual sampling frequency appears (flashing). Different times must then be corrected accordingly. The numerically displayed measured values are corrected automatically.

During a swipe action "from bottom left to top right", the APP goes into a diagnostic mode. Then the actual sampling frequency, the standard deviation of the sampling frequency and an internal counter appear.

Underneath figure "Accelerations over time":

It shows the accelerations curve of the last 5 seconds. After pressing STOP, a window of 1.28 sec is marked (vertical black bars).

in PRO version: the window can be moved by ±, after a double-tap on the figure it appears twice as large, after another double-tip it is resized again. Swipe up, swipe down to change the scaling.

Underneath figure "Largest of the three acceleration components curve":

It shows the acceleration component with the maximum acceleration change. The zoom window is represented by 1.28 sec. It is particularly suitable for oscillation frequencies from 1 Hz to 15 Hz. The more sinusoidal the time signal, the more secure are the determined values. In diagnostic mode, trigger points and sine approximations are visible.

In PRO version: after a double tip on the figure it appears twice as large, after another double-tip it is resized again. Swipe up, swipe down to change the scaling.

Underneath figure "Numerical evaluation from the time signal":

Here evaluations from the time domain are displayed numerically. In the diagnostic mode, the number of detected vibrations are displayed. Sx is their standard deviation. The larger n and smaller Sx, the safer the values determined. The acceleration amplitude also specifies a standard deviation. The calculation is done with the least square method.

Underneath figure "FFT-writing of the acceleration over time":

Here, a plot of the acceleration spectrum over time is shown. Shown are the last 5 seconds. The zoom window is marked.

In PRO version: after a double tip on the figure it appears twice as large, after another double-tip it is resized again. Swipe up, swipe down to change the intensity scale.

Underneath figure "FFT spectrum of the zoom window":

It shows the FFT spectrum within the zoom window. The black curve is the resulting acceleration.

In PRO version: after a double tip on the figure it appears twice as large, after another double-tip it is resized again. Swipe up, swipe down to change the scaling.

Underneath figure "FFT, numeric":

It is the numeric output of the FFT spectrum within the zoom window. The maximum of the FFT is indicated by a cross. Frequency, Amplitude and maximum acceleration values are shown.

vibration analysis

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