Advanced Filtering for Vibration Analysis

Broadsens recently enhanced its filtering ability in the vibration analysis software BroadVibra 2.5.8. In this release, the negative edge effect is removed, which allows for more accurate time-domain and frequency domain vibration analysis. When the software is used with ultra-low power wireless vibration sensors SVT200-A, SVT300-A and SVT400-A, the system provides one of the most advanced filtering ability for machine condition monitoring and predictive maintenance. BroadVibra vibration monitoring and analysis software is installed inside the wireless gateways with life-time license. Users do not need to pay subscription fee to use the software, which can save the cost in the long run. Moreover, the software comes with 1-year free tech support and upgrade.

vibration analysis with FFT and high-pass filter

Figure 1. High pass filter with edge effect

In Figure 1, a 4th order high-pass filter is applied to the vibration signal. The vibration signal is obtained from a SVT200-A wireless vibration sensor mounted on a industrial fan. The wireless vibration system is used for industrial fan  vibration monitoring. The wireless vibration sensor takes triaxial raw acceleration data and send them to the wireless gateway. The data acquisition mode is "single DAQ" mode, in which 4,096 sample points are taken. The sampling rate is set at 3.2kHz. The data resolution is 16-bit.

At the very beginning of Figure 1, if you look closely, then you may notice that there is an edge effect of the filtering data. This is due to the reason that all filters have a transient effect, which needs a short time period to settle. The edge effect is especially obvious in z-axis in this testing.

Figure 2 removes the x and y axes, and zooms in the beginning of the z-axis curve. You can clearly see the edge effect in Figure 2. In Figure 3, the edge effect is removed automatically in the BroadVibra vibration analysis software version 2.5.8 and above. This allows more accurate time-domain and frequency domain vibration analysis.

Vibration FFT analysis edge effect

Figure 2. Zoomed in edge effect at z-axis

Vibration analysis edge effect removed

Figure 3. Edge effect automatically removed

The BroadVibra vibration analysis software allows user to select high-pass, low-pass and band-pass filtering, plus continuous adjustment of the cutoff frequency. The filtering order can be selected from 4th order, 8th order and up to 12th order. With the advanced filtering ability and FFT analysis at the edge-computing gateway, Broadsens offers some of the best wireless vibration sensors in the industry.