Navigation:  Tutorials > Measurement tutorials > Vibration > DEWESoft 7.0  data acquisition, processing, analyzing and storage software Math setup

The second step is to calculate the vibration velocity and the displacement. This can be achieved in the math section with the filter, since the integrator is actually nothing more than a filter.

We enter two IIR filters in the setup - first will be the integrator (for calculation of vibration velocity) and the second one will be the double integrator (for measurement of the displacement).

 

Let's go to the channel setup of the first filter. First, we need to choose the input channels. Since earlier the second channel was the upper accelerometer, we must deselect Vib1 and select Vib2 . It is quite a common error to forget to choose the correct input channel, so it is advisable to do this step first.

Then we should choose the integrator. Since the DC offset is merely an error in measurement and calculation, we need to set up the high pass filter (in Flow field) to cut off the DC offset. For single integration, the Order of the filter needs to be at least two (if filter order is one, there will be static offset left in the result, if there is no filter, it will drift away).

Next, we enter the units. If the integration is from acceleration to velocity and the acceleration unit is m/s2, the output unit is normally m/s. Since this unit will be too large, it is helpful to enter the scaling factor of 1000 and then have mm/s as the units.

As can be see in the preview, the vibration on the shaker is quite large. On normal machinery (where the vibration is an unwanted side effect), the vibration value of velocity should not exceed 10÷15 mm/s.

 

Since the movement of the structure will observe with the camera, it would be interesting to know the vibration displacement. For this, we should setup another channel by again selecting Vib2 and selecting double integration. Since the double integrator is in fact a second order filter, we need to set the high pass filter to the Order at least three or higher. Usually the displacement caused by the vibration is not visible by the eye, and is measured in micrometers, but since this measurement has quite high values, the output unit was set to be in mm . The scaling factor is therefore again 1000 . We can already see in the preview that the peak-peak movement is around 15 mm and since this is a value which can be confirmed with the eye, we can be sure that the scaling factors and the settings are correct.

 

Now the video camera needs to be set up and then we can see what's going on.