Effects of the electromagnetic disturbances in the DAQ-based measurement instruments and their compensation

In previous works, we analysed the behaviour of data acquisition board based measurement instruments when they are subjected to the electromagnetic disturbances prescribed by the IEC-61326 Standard. The study has shown that the effects of both radiated and conducted emissions alter the performances of this instrumentation when not-shielded configurations are used; in fact, in these cases, the parameters which characterise a data acquisition board can reveal an appreciable degradation. On the contrary, even the heaviest disturbances cause a negligible impact if the good practices of shielding are observed. Since the full-shielded configurations are quite expensive, it would be useful to find a way to safely employ also a not-shielded configuration in the hostile electromagnetic environments. With this aim, in the paper, we propose two methods for the compensation of the electromagnetic disturbances impact. The first one is a software approach, applicable in cases of steady disturbances. The second approach is based on a two channels acquisition technique applicable with boards which can simultaneously acquire two signals. The practical application of both methods has produced satisfactory results.