Selecting the Right Vibration Sensor: A Comprehensive Guide

Choosing the right vibration sensor is paramount to ensuring accurate data collection and effective maintenance strategies. In this blog post, we will provide a comprehensive guide on how to choose the best vibration sensor for your specific needs. 

Understand Your Application
The first step in selecting a vibration sensor is to thoroughly understand your application. Consider factors such as the type of machinery, the criticality of that machinery, the frequency range of vibrations, and the environmental conditions in which the sensor will operate. This initial understanding will help you narrow down your choices. 

Process Monitoring vs. Dynamic Vibration Analysis
The next step is determining if process monitoring or dynamic vibration analysis is right for your application. Process monitoring requires 4-20mA Loop Power Sensors, which will provide the overall vibration level of the machine so that it can be trended and alarmed using the plant’s DCS, PLC, or SCADA system. Process monitoring will require permanently mounted loop power sensors that output a 4-20mA signal proportional to velocity or acceleration. Process monitoring will provide an overall understanding of machine health, but cannot provide the same level of detailed diagnostic data as Dynamic Vibration Analysis. Process monitoring is a cost-effective way to get an understanding of machine health. 

Dynamic Vibration Analysis allows for trended data and machine health diagnostics. It can involve either permanently mounting sensors or portably mounted sensors used in route-based data collection. This method provides more insightful data than process monitoring but is typically more expensive. 

If dynamic vibration analysis is the right predictive maintenance approach for you, continue reading for more important considerations  

Consider Measurement Range and Frequency 
Determine the range of vibrations your application needs to measure. Some sensors are designed for low-frequency vibrations, while others excel at capturing high-frequency vibrations. Ensure that the sensor's measurement range aligns with your specific requirements to avoid distortion or under-sampling of data. For the majority of applications, general purpose, 100 mV/g accelerometers can be used. These sensors typically have a frequency range between 30-900,000 CPM. 

Evaluate Sensitivity and Resolution 
Sensitivity refers to a sensor's ability to detect small changes in vibration, while resolution is its capacity to distinguish between different vibration levels. Higher sensitivity and resolution are crucial for accurately capturing subtle vibrations, making them important considerations when choosing a sensor. 

Environmental Conditions 
Consider the environmental conditions in which the sensor will operate. Some sensors are designed to withstand extreme temperatures, while some are intended for regular, general-purpose applications. In general, sensors with 316L stainless steel cases will provide the best corrosion resistance on the market. It is also important to ensure that the sensor connector and cabling have the right chemical compatibility and temperature resistance to ensure a reliable connection to your sensor. 

Form Factor 
In some applications, clearance is a concern. Side exit sensors are designed for applications where height clearance is a problem, and a lower profile is needed. Top exit sensors are typically lighter weight than side exit sensors and therefore have a better high-end frequency response. 

Selecting the right vibration sensor is a critical decision that directly impacts the effectiveness of your vibration monitoring and maintenance efforts. Investing time and effort into choosing the right vibration sensor will ultimately lead to improved machinery reliability, reduced downtime, and cost savings.