Digital Multirange 3Axis MEMS Accelerometer for Railway Applications

In many mechanical applications, measuring accelerations along three orthogonal directions is very important. Especially in railway application a rugged, easy-to-configure and low-noise device could be useful to measure the dynamics of the train. Moreover, freight or passenger trains behave very differently and for homologation purposes accelerometers have to be placed both on the axel-boxes, on the bogies and on the carbody. Therefore, accelerometers with different scales along X,Y and Z axes are required. The present paper presents the design, calibration and test on a freight train of new low cost MEMS accelerometers having sensibility that can be interactively adjusted between ±2g, ±16g and ±40g independently over the three axes. The output of these accelerometers can be set either to digital or to analog (with compensation of the cable length). In the paper the design of the nodes both from the electronic and mechanical points of view is presented. The results of the calibration and of the experimentation are also shown.