User Manual
Slam Stick User Manual
Version No. 2.0
75
This happens because the accelerometer's charge amplifier is saturated due to experiencing
acceleration outside its measurement range. PCB Piezotronics has a very good
detailing why this occurs. Some customers are hesitant to believe that such a high
amplitude acceleration occurred; what often happens though is that a high amplitude and
high frequency acceleration occurred. It can be so high frequency that it will take place between
samples even when sampling at 20 kHz. When such a high frequency impact happens though
there is very little energy in the impact so engineers can ignore the data.
When you see this happen you have a few options. You can get a unit with a higher measurement
range. Or you can try and use some type of mechanical filter such as duct seal putty to filter out
this high frequency acceleration. The structure that the Slam Stick is mounted to should also be
looked at to ensure it isn't hitting its own natural frequency during these events. Some customers
use mounting fixtures which aren't stiff enough which can amplify shock/vibration events. Lastly,
you can continue using the unit you have in the same manner (these events won't damage the
Slam Stick); and ignore the half second or so of data during these decays.
Can the Slam Stick Lab integrate for velocity or displacement?
The software can’t currently do any integration, great question though! The
export data though to both MATLAB and Excel so that the engineer can do some post processing
themselves. Here’s a
to a simple function in MATLAB that can perform an integration of
numeric data. There’s also a few Excel examples out there that do a similar trapezoidal
integration. We are working on adding this functionality into the Lab at some point this year; but
there are quite a few other features that are currently higher up on the list.
If you need displacement data, we encourage you to focus the integration to acceleration
channels recorded with a DC response accelerometer. Because the higher frequency/amplitude
accelerometer in the Slam Stick X is an AC-response accelerometer, the output of this device will