GNGTS 2022 - Atti del 40° Convegno Nazionale

168 GNGTS 2022 Sessione 1.3 isolate it from external temperature variations, and it is additionally connected to a battery to maintain the device in operation and at the right temperature in the case of a power failure. For the inclination, the tiltmeter Model 714 from Applied Geomechanics was utilized. It is capable of measurements with an angular range of ±8000.0 μrad, a resolution of 0.1 μrad and a linearity of 2% within the full span. Dual signals are used to measure the inclination in each of the two axes. Additionally, it measures the ambient temperature and its power supply (Applied, n/d). As an acquisition system, the Agilent 34970A data acquisition and switching unit was utilized for this measurement node. With 6.5 digits of resolutions (22 bits) and a 0.004% accuracy for measuring DC voltage and the ability to monitor up to 120 channels with expansion cards, it proves to be adequate for this project (Agilent, n/d). After initial testing with more than 500 measurements of 8 different analog channels, the reading delay is 7.99 ms with σ = 2.06 ms for consecutive channels within the same scanning list and 140.0 ms with σ = 49.4 ms when changing from a scanning list to another one. All this equipment was then calibrated on site according to manufacturers guidance to ensure the correct operation. The measurement node is located on Cube 41 B at Universitá della Calabria in Arcavacata di Rende, Cosenza. An underground / basement location was chosen to avoid noise from natural vibrations of the building that occur at higher floors and to avoid the disturbance of bystanders. Lastly, atmospheric information is supplemented fromametrological station located in the same university at Cube 41 C (within 20 m from the measurement node) via internet for the processing of the obtained data. Figure 1 shows the connection scheme of the diverse systems, while figure 2 shows images of the onsite implementation. On the software side of the measurement node, custom software was developed in LabView that is in charge of: sampling the 8 signals with a sampling period of 5s, convert time Fig. 1 - Scheme of Connection of the Gravitational Node. Fig. 2 - On-site Implementation of Gravitational Node.