Tip of the Month
using adapters when calibrating...
reference accelerometers typically have a ¼-28 or 10-32 mounting
thread. Sensors under test (SUT) often require a different thread
interface. In these cases, mechanical adapters must be used to
allow for an appropriate mate. Unfortunately, adding this mechanical
adapter also adds mass and reduces stiffness between the reference
and SUT, which effectively reduces the mounted resonant frequency.
The result may be an out of tolerance condition in the upper
frequency range, say 10 kHz. The best practice is to avoid using
adapters if possible. As this may be unreasonable with certain
SUT's, the next best practice is to use as small of an adapter as
possible, with proper torque and ample silicone lubricant at each
mating point. Keep in mind that if you are having trouble comparing
calibration data at higher frequencies with the OEM or another
calibration laboratory, it is important to understand if both labs
are using similar mounting conditions. If not, this may be a
substantial contributor to measurement uncertainty.
- Basics of Accelerometer Function; How
Standards Link Together
- Shear, Compression, Flexure; ISO 16063 Overview
- Accelerometer Transduction Types (PE, PR, VC);
Laser Primary Calibration