描述
PLC控制系统的输出电路设计。依据生产工艺要求,各种指示灯、变频器/数字直流调速器的启动停止应采用晶体管输出,它适应于高频动作,并且响应时间短;如果PLC系统输出频率为每分钟6次以下,应首选继电器输出,采用这种方法,输出电路的设计简单,抗干扰和带负载能力强。
如果PLC输出带电磁线圈等感性负载,负载断电时会对PLC的输出造成浪涌电流的冲击,为此,对直流感性负载应在其旁边并接续流二极管,对交流感性负载应并接浪涌吸收电路,可有效保护PLC。
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