描述
I/O单元实际上是PLC与被控对象间传递输入输出信号的接口部件。I/O单元有良好的电隔离和滤波作用。接到PLC输入接口的输入器件是各种开关、按钮、传感器等。PLC的各输出控制器件往往是电磁阀、接触器、继电器，而继电器有交流和直流型，高电压型和低电压型，电压型和电流型。
RELIANCE ELECTRIC 0-57404-2 USPP 0574042
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RELIANCE ELECTRIC 1SU41003 NSPP 1SU41003
RELIANCE ELECTRIC 0-55325-77 USPP 05532577
RELIANCE ELECTRIC 0-55325-77A USPP 05532577A
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Reliance Electric P21G4215
RELIANCE ELECTRIC 60021-1 USPP 600211
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RELIANCE 6SP201-015BTAN SP600 5HP 230V AC DRIVE*XLNT*
