The widely deployed and popular 2-wire 2-20 mA IEPE standard for acceleration piezo-based sensors complicates cable or system testing in the field but equally in the (R&D) lab. Many field engineers build their own hand-made test device...
...stick a motor with imbalance, or a tiny vibrating motor, onto a piezo-sensor with a tape...
Obviously, such a hand-made test device only allows us to prove a working or broken cable connection but not its frequency response. We all know, wrongly selected cables or very long cables can lead to constrained bandwidth and then impair signal quality. They limit the system's ability to detect early defects, appearing in the higher frequency bands typically above 10 kHz. Sometimes one also wishes to test the whole signal chain inclusive the shielded cables, connectors, the Edge-Device and the data analysis in the Cloud.
Thus Mechmine developed for its internal use, and offers this as a product now, a handy unit which generates pre-defined signals. There are four rms Voltage levels and 16 frequencies to chose from, all digitally generated by a processor and hence stable and accurate. There is an AUX BNC input which allows connecting the unit to an arbitrary signal generator or an audio output on a PC/Laptop (i.e. soundcard). So everyone can write with a few lines of (Python) code a signal generator or replay audio files like wav or mp3. This enables the enginer skilled in the art also to generate AM and FM signals and test envelope, square-envelope or order-tracking algorithms. The unit is powered by a 12 VDC power adapter and could be powered by batteries also.
The figure below shows a typical test scenario.
