Understanding Vibration Monitoring and Frequency Limits
Effective vibration monitoring plays a critical role in managing risks and ensuring the structural integrity of buildings and infrastructure. However, it requires proper configuration and understanding of the tools and data to avoid common pitfalls. Below, we discuss key aspects of vibration monitoring, including the use of frequency graphs, trigger settings, and interpreting breaches, as demonstrated in the graph below.
Setting Triggers and Managing Data
When using vibration monitors, it is essential to set triggers correctly. The trigger should be designed for specific, one-off breach occurrences where the vibration limit is exceeded. This approach ensures the system captures the dominant frequency for each channel during a breach. However, care must be taken:
Avoid Unrealistic Trigger Settings: Setting overly sensitive triggers can generate excessive data streams, quickly consuming SIM data and potentially overloading the monitor’s memory. This can cause the monitor to stop functioning.
Purpose of Triggers: The system is intended to capture the frequency of a single, significant breach. This is because low-frequency vibrations tend to cause more damage than high-frequency vibrations. Properly configured triggers help identify these instances without overwhelming the system.
Frequency and Vibration Damage
The impact of vibration varies significantly based on frequency. As shown in the graph below, low-frequency vibrations (e.g., around 4 Hz) are more likely to cause damage compared to higher frequencies (e.g., 40 Hz). This is reflected in the transient vibration guide values for cosmetic damage:
Line 1: Represents the general limit across frequencies.
Line 2: Shows how the maximum limit increases at certain frequencies, rising from 15 mm/s to as high as 50 mm/s.
This means that at higher frequencies, vibrations can exceed the default lowest limit (e.g., 15 mm/s) without necessarily causing damage. For example:
A reading of 7.29 mm/s at 46.87 Hz would not exceed the limit and would be considered safe.
A reading of 20 mm/s at 46.87 Hz would still fall within acceptable limits due to the frequency-dependent increase in thresholds.
Thus, while an alert might be triggered at the default 15 mm/s limit, further investigation using the frequency graph can reveal whether the breach is genuinely concerning or not.
Interpreting Data with Sonitus Cloud
The Sonitus Cloud platform captures velocity data in mm/s for each channel, enabling detailed analysis of vibration events:
Frequency Plots: These plots provide insights into how the waveform decays over time. By analysing the decay pattern, you can:
Determine if the breach was a one-off occurrence.
Identify potential tampering, as tampered waveforms often differ significantly from expected patterns.
Dominant Frequency Identification: The system pinpoints the dominant frequency during a breach, allowing for more precise assessment of its potential impact.
Practical Implications
For users monitoring sites with vibration-sensitive infrastructure, understanding these principles is essential:
Set realistic trigger levels to avoid unnecessary data overload.
Use frequency graphs to determine whether a breach poses a genuine risk.
Recognize that frequency-dependent limits provide greater flexibility for managing higher-frequency vibrations without unnecessary alarms.
By leveraging tools like Sonitus Cloud and interpreting frequency plots accurately, users can make informed decisions and maintain efficient, reliable monitoring systems.