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Analysis of MCU leakage detection and alarm circuit

Release Date: January 9, 2018

Because the electrical control system has a complicated working environment, it needs to have the function of leakage detection and alarm. Leakage detection The output of the leakage detection coil is reshaped and input to the RC6 port. The circuit schematic is shown in Figure (a). When the leakage current exceeds a certain threshold, the comparator outputs a low level, otherwise it keeps a high level, and then generates a waveform as shown in (b) by a monostable flip-flop circuit. The low-level holding time t can be monostable. Trigger to adjust settings. In this system, t is 10ms. Since the PIC16C57 has no interrupt function, the RC6 port must be queried at a certain interval (less than 10ms) in the program to detect the leakage . Once RC6 is detected to go low, an alarm will be issued after confirmation. At the same time close the control valve. The PIC16C57 itself has a watchdog timer, which automatically performs power-down protection and system reset when the system is abnormal.