# Wireless Data Acquisition System with Feedback Function
## 3 Results and Discussion  
Figures 13 and 14 show screenshots of the process of monitoring the voltage and current of four series-connected SWPP batteries. When recording them, the voltage deviation of individual batteries was simulated by temporarily replacing the corresponding battery with a regulated laboratory power source. Figure 12: Appearance of DAS receiver removed from case: LCD (1), buzzer (2), USB cable (3), resistor (4), backup battery for powering RTC (5), LED (6), diode (7), oxide semiconductor capacitor (8), RTC chip (9), quartz resonator RTC (10), tuning capacitor (11), button to turn on/off mode of generating IR pulses for polling sensors (12), receiver radio module (13), and microcontroller platform Arduino nano (14). Figure 13a shows the nature of the recorded information at permissible voltages (12-14 V) of the power batteries. Backup protection is not required in this case. Figure 13b,c show the system's reaction to overdischarge of the first and third batteries below the permissible limit (<12 V). In both of these cases, to prevent battery failure, backup protection issued a command via an infrared channel to turn off the load (or switch it to power from the city network). It should be emphasized that backup protection is triggered only in cases where the standard controllers of solar panels and wind generators for some reason cannot ensure normal operation of the batteries. If the battery was overcharged above the permissible limit (>14 V), the system issued an IR command to turn off the charging circuit of the entire section of series-connected power batteries, as shown in Figure 14. If it is necessary to organize backup protection and against short circuits, faster equipment should be used. As a result of the research, the authors formulated the principles of constructing a wireless DAS for low-power GEPPs free from some of the disadvantages of analogues, and developed and implemented \"in hardware\" a wireless intelligent current and voltage sensor and equipment for indicating and recording data received from several such sensors. Successful tests of the DAS organized in this way in the hardware room of the \"Green Energy\" power plant of ToU confirmed the correctness of the design principles, circuit solutions, and program algorithms embedded in the developed system. The distance from the installation sites of the sensors to the installation site of the receiving equipment in the equipment room does not exceed 4.5 m; so, the result of the range tests should be  
Figure 14: A screenshot of the process of monitoring the voltage and current of SWPP batteries with a recorded case of overcharging battery No. 2. Figure 13: A screenshot of the process of monitoring the voltage and current of SWPP batteries. interpreted as the possibility of error-free data reception using the described equipment with a four-fold margin in range. Appendix D and Video S1: \"Distance Test\" illustrates the range of the sensor. In addition to solving the main problem of organizing wireless data collection, the authors managed to provide many additional useful functions that were not available in known analogues:  
* The use of an infrared communication channel in the described DAS in addition to the radio channel makes it possible not only to organize a feedback channel with SWPP equipment protected from outside interference, but also to implement on this basis backup protection of SWPP equipment from damage and abnormal operating conditions (PDAOCs). In the future, this will make it possible to transform the data collection system into a full-fledged automatic control system (ACS) for the operation of the SWPP with relay protection functions for all of the main elements of the SWPP. * The construction of sensors and other equipment based on mass-produced, widely available electronic components and modules facilitates the organization of their mass production.