How to choose an accelrometer

When selecting any of the three types, it’s important to ask the following:

• What is the vibration level and frequency range?
• What is the temperature range?
• Is the environment corrosive or atmosphere combustible?
• Are intense fields (electromagnetic or acoustic) involved?
• Is there substantial ESD present?
• Are there sensor size and weight considerations?

For vibration analysis and condition monitoring, look at sensors with an AC or charge output. For continuous monitoring and machine protection, sensors with DC output are a better choice.

Five main features must be considered when selecting vibration sensors: measuring range, frequency range, accuracy, transverse sensitivity and ambient conditions. Measuring range can be in Gs for acceleration, in/sec for linear velocity (or other distance over time), and inches or other distance for displacement and proximity.

Frequency is measured in Hz and accuracy is typically represented as a percentage of allowable error over the full measurement range of the device. Transverse sensitivity refers to the effect a force orthogonal to the one being measured can have on the reading. Again, this is represented as percentage of full scale of allowable interference.

For the ambient conditions, such things as temperature should be considered, as well as the maximum shock and vibration the vibration sensors will be able to handle. This is the rating of how much abuse the device can stand before it stops performing, much different from how much vibration or acceleration vibration sensors can measure.