Uncertainty and reproducibility in measuring data acquisition system immunity to conducted disturbances

The paper presents an original methodology for testing the data acquisition system immunity to conducted disturbances and for evaluating the typical uncertainty intervals to be assigned to these kinds of measurements. As in any data measurement system, even in those consisting of a desktop computer equipped with a PCI data acquisition board, several devices and components are involved in the process of acquiring, sampling and digitizing the analogue signal, and eventually presenting the digital values to the user. Therefore, there are many possible coupling paths between the measurement system and external electromagnetic disturbances, in principle both radiated and conducted, which would require a large number of configurations to be tested. Indeed, with particular reference to radiated couplings, their effects generally depend on the adopted test setup. In addition, the electromagnetic boundary conditions of the test site can significantly affect the measurement results. Both these aspects should be carefully taken into account because they are the main cause for ambiguous results and well-known issues in inter-laboratory comparisons. In this framework, the aims of this study are (i) to investigate which components or component configurations influence the data acquisition system immunity most significantly; (ii) to provide a practical way to effectively test these types of measurement system and (iii) to assess the related uncertainty budget in order to qualify the test results. Finally, the site-to-site reproducibility of the measurements has been evaluated by comparing results obtained in two different laboratories.