## 2 Materials and Methods
### Equipment for Testing  
**cRIO**: The cRIO-9054 model acted as a \(\upmu\)PMU and oversaw the maintenance of the reference as a TSN master for all the captures in an area distributed throughout the plant. It integrated a GPS module to maintain a universal UTC reference. This equipment oversaw the capture, the processing of the measurements, and the temporary storage of the TDMS files which contained the time series. It was possible to carry out this operation with real-time processing techniques. The operating system running this equipment was Linux Real Time (LRT). **cDAQ**: Specifically, the cDAQ-9185 models were automatically synchronised with the reference deriving from the cRIO-9054 located in the same local network. The cDAQs integrated a 100 MHz oscillator and could be synchronised on a subnetwork with the TSN standard. With this method, analogue inputs integrated in C-Series modules that were inserted into the cDAQs could be synchronised for simultaneous sampling. **Analogue inputs**: Two types of C-Series modules were used for data acquisition. The NI-9215 with four 16-bit inputs, Successive Approximation Recording, and simultaneous capture had \(\pm\)10 V voltage input and a maximum sampling of 100 kS/s per channel, while the NI-9242 and NI-9246 modules had channels for three-phase voltage and current measurements. They included Sigma Delta converters with a maximum sampling of 50 kS/s, equivalent to 51,200 samples per channel, and a resolution of 24 bits. Specifically, NI-9242 modules were used for the tests, which did not require an external reference but did measure with respect to the neutral. These modules used high-precision resistors for the internal dividers, specifically the VMN family \"high voltage monitoring resistor networks\" (from Caddock Electronics Inc., Glide, OR, USA). They feature tolerances of up to 0.02% and temperature coefficients of up to 5 ppm/\({}^{\circ}\)C. They are high impedance resistive dividers with very low power consumption from the network. **Voltage transducer**: Three active LEM LV-25 transducers were used to capture mains voltages with the NI-9215 modules. These modules provide galvanic isolation between the primary and secondary circuits, and require a \(\pm\)15 V symmetrical power supply. The output voltage can be adjusted with a precision resistor to achieve maximum output sensitivity. In these tests, it was calibrated with a Fluke 5522 A multi-product calibrator, which provides a waveform equivalent to the mains voltage. Since the maximum peak voltage allowed by the NI-9215 modules was Vp = 10 V, there was a 20% margin for measuring overvoltages. **Routers**: In the first phase, the tests were carried out by connecting the equipment to a local area network with a Linksys WRT54G router, with speeds of 10/100 MB, which could work with the free DD-WRT firmware [21]. This software runs on a reduced operating system based on GNU Linux. With this method, standardised test conditions could be defined to facilitate traffic control, the emulation of different data flow levels, and the collection of the activity of the connected equipment with the \"RFlowCollector\" tool. Moreover, it was possible to establish Quality of Service (QoS) rules to prioritize the traffic of the equipment of interest. For the second phase tests, the ASUS RT-AC66U router was used with speeds of 100/1000 MB and worked with the ASUSWRT native firmware, which allows for securely managing access with OpenVPN clients to any server of the University of Cordoba. Additionally, it was possible to establish QoS rules to prioritise the traffic of the equipment of interest. The tests analysed the level of stability achieved when the devices were synchronised with continuous UDP packet transfer according to the IEEE 802.1 AS standard and when connected to a local area network with a controlled flow. **Ethernet cable**: The type of Ethernet cable chosen was suitable for the transfer capacity of the two router models.