Design of mine-used multifunctional thermal resistance type isolation safety barrier

In view of problems of poor anti-interference performance, low integration and single function of common thermal resistance type isolation safety barriers, a mine multifunctional thermal resistance type isolation safety barrier was designed. The safety barrier uses DC/DC isolated power supply module with two mutually isolated outputs to supply power to safety side and dangerous side circuits respectively, and realizes three-terminal isolation of power supply side, dangerous side and safety side combining with signal optocoupler isolation.It has functions of quadratic nonlinear error correction for thermal resistance, thermal resistance sensor disconnection fault alarm, high temperature alarm with hysteresis, voltage and current signal output conversion and so on. The prototype test results show that: two thermal resistances can work at the same time, and the threshold comparison circuit operates steadily; with the input temperature increases, the output current basically increases linearly, the linearity is as high as 0.15%, and the corresponding analog output transmission processing error is less than 0.5% , which meets requirements of relevant regulations; it effectively suppresses the interference of spikes and various noise, and has good anti-interference performance; the maximum relative error is only 0.667%, which is lower than the similar type of XX6071 safety barrier. The actual application results verify that the temperature measurement results of the safety barrier are accurate and the high temperature alarm action is stable, which meets the actual application needs of mine electrical equipment.