IC697CHS790通用电气框架电磁干扰的传输和传输途径 电磁干扰的发生必然存在干扰能量的传播和传播通道。干扰的传输有两种基本方式：传导和辐射。辐射耦合细分为：天线对天线耦合、场对线耦合和线对线耦合。针对干扰的传播和耦合途径，在汽车电器工程实践中要采取如下的系统方法来改善EMC特性：滤波、屏蔽、搭铁和布线。 2 干扰源和敏感设备的电磁兼容设计 在方案已定的功能电路中，检验电磁兼容指标是否满足要求；
IC697CHS790通用电气框架此时如不满足要求，则可通过参数修改来达到指标，如调整数字化控制器的工作频率、圆整脉冲的上升率或重新选择元件等。其次进行防护设计，包括滤波、屏蔽、搭铁与搭接设计，甚至采用时空隔离和频率回避等改进措施。最后是做布局调整性设计，包括对总体布局的检验、屏蔽体缝隙的检验、组件和印制板布局检验等。电路和分系统的电磁兼容设计包括如下的步骤：元件选择、电路选择、滤波技术应用、搭铁设计、屏蔽设计、电路布局和系统布局规划ESD防护设计 为了消除静电放电的危害，可采取的措施有：建立完善的屏蔽结构，通过搭铁的金属壳将静电荷释放到地；内部电路与金属壳的连接应采用一点搭铁；增加诸如硅瞬变电压吸收二极管（STVS）之类的快速保护元件，将高压电荷泄放到地；印制电路板设计中增加保护环带，将人手拔插线路板的电荷通过最短的路径泄放到地。汽车行驶记录仪的抗干扰设计 1 汽车行驶记录仪的硬件结构 图1为汽车行驶记录仪硬件结构原理。信号的抗干扰处理是通过光电隔离来实现。车载设备的电源系统对设备的可靠运行影响很大，好的电源电路能够过滤掉许多通过电源线传入的干扰信号。 2 电源部分的抗干扰设计 本控制模块的电源电路如图2所示。车载蓄电池—发电机的电源从24V_1处进入，二极管D16主要是防止电源的正负极被误接反。电感L1、L2对电源进行滤波，和共模电感L3、电容C8配合，可以过滤掉电源中的尖峰脉冲。二极管D24 P6KE51A是脉冲干扰抑制器（TVS），它可以快速吸收超过额定电压的尖峰脉冲，瞬时通过电流很大，最大功率可达500～1000W。电容E5和C9进一步对电源进行滤波。but at present, the main drainage system in coal mines is still controlled by relays. The start and stop of water pumps and the selection and switching are manually completed, and the automatic start and stop of water pumps according to the water level or other parameters cannot be achieved, which will seriously affect the management level and economic benefits of the underground main drainage pump room. Daizhuang coal mine is a modern mine with a production capacity of 1.8MT / A, which was designed and completed in 1999. The underground water inflow is large. The central pump is designed and installed with five md500-57-9 main drainage pumps, supporting motors of 1250KW, and three drainage pipelines. During normal water inrush, two are in operation, two are for standby and one is for maintenance. In view of the progressiveness and reliability of PLC, Handan Design Institute of coal industry has implemented PLC automatic control, automatic detection and dynamic display of operating parameters for five main drainage pumps and their auxiliary vacuum pumping systems and pipeline electric valves,
