## 2 The Measuring System for Monitoring Vibrations of Building Structures
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline DAQ type & Dynamic signal acquisition module \\ Number of channels & 3 input channels \\ ADC resolution & 24 bits \\ Type of ADC & Delta-Sigma (with analogue prefiltering) \\ Input signal range & \(\pm\)30 V \\ Sampling mode & Simultaneous \\ Frequency (internal time base) & 13.1072 MHz \\ Accuracy (internal time base) & \(\pm\)100 ppm \\ Data rate range using internal time base & 0.985–12.8 kS/s/channel \\ Noise at maximum sample rate & 106 \(\mu\)V \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Selected parameters of the data acquisition card. Figure 5: View of the card and the computer unit before and after mounting in the housing. the housing material does not generate flaming drips. The housing is locked to protect the measurement system from accidental interference. In order to ensure reliable data, the system has been checked and will be checked periodically for errors. The sensor (accelerometer) was calibrated in an accredited calibration laboratory, No. AP 006 (Main Mining Institute, National Research Institute, Research and Calibration Laboratory Team, Katowice, Poland). The parameters of the sensor have been confirmed by the calibration certificate No. 6128 of 10 February 2022. The error estimator is the standard deviation expressed in %. The standard deviation values for the transducer output signal in the x, y, and z planes is between (\(-\)2.23) and 3.36% (Figure 7). The obtained values were confirmed by the information provided by the manufacturer in the sensor data sheet (Table 1). The measurement system was validated through an interlaboratory comparison to meet the requirements for accurate measurement. The standard [43] indicates the possibility of performing validation using one of the following methods:  
* Calibration or evaluation of bias and precision using reference standards or reference materials,
* Systematic assessment of the factors influencing the result,
* Testing method robustness through variation of controlled parameters, such as incubator temperature volume dispensed,
* Comparison of results achieved with other validated methods,
* Interlaboratory comparisons,
* Evaluation of measurement uncertainty of the results based on an understanding of the theoretical principles of the method and practical experience of the performance of the sampling or test method. The results of the developed measurement system were compared with the results obtained by an accredited laboratory. Accredited laboratories maintain metrological traceabil  
Figure 6: View of the apparatus during preparation for tests. Figure 7: Fragment of the accelerometer calibration certificate (the error estimate is marked in yellow). ity of their measurement results by means of a documented unbroken chain of calibrations, linking them to an appropriate reference. The interlaboratory comparison was carried out together with the accredited research laboratory No. AB 1407 (Silesian University of Technology, Field Research Team, Gliwice, Poland) in October 2022. The interlaboratory comparison was performed in three locations (buildings), with three series of measurements in each location. An artificial source of vibrations was used, which was a diesel soil compactor. Measurements were carried out for two vibration planes. Peak acceleration was recorded. The results were compared using the En indicator in accordance with the standard [44]. The obtained value of the En indicator should be interpreted as follows:  
* \(|\,\mathrm{En}\,|\,\leq 1\)--comparison result \"satisfactory\", no additional action is required. * \(|\,\mathrm{En}\,|\,>1\)--result of the comparison is \"unsatisfactory\", corrective action should be taken. The maximum value of the En indicator for measurements obtained from the described measurement system, after comparing with the values of an accredited testing laboratory, did not exceed 0.32 (\(|\,\mathrm{En}\,|\,\leq 0.32\)).