Davidson Measurement Tech Tips

Cable & Signal Loss

When it comes to vibration, there are many causes of noise on the signal from a sensor. One of those sources can be minimised by some simple actions and this tech tip offers one solution for you.

When vibration sensors are installed, people usually take good care mounting the accelerometer correctly by drilling and tapping a hole to accept the sensors mounting stud. The accelerometer is screwed into place and the cable connected.

Unfortunately, this is where some of the problems start. It is important to ensure the cable is secured firmly to some portion of the structure as shown.

The need to have secure cable mounting is to reduce "triboelectric" noise, i.e. noise generated by the flexing of the cable under vibration. The capacitance of the cable can change when the cable itself is vibrated, this then creates noise on the output signal. Such phenomena is especially critical when using any high impedance accelerometers, pressure or force transducers. Even low impedance sensors can be affected if care is not taken.

So make sure your cable is well tethered and you will help remove a source of potential noise.