与开关输出一样，每个逻辑线圈占用系统 RAM 存储区中的一个位，但不能直接驱动外设，只供用户在编程中使用，其作用类似于电器控制线路中的继电器。 另外，不同的 PLC 还提供数量不等的特殊逻辑线圈，具有不同的功能。
ELECTROCRAFT THERMALLY PROTECTED 115V 1/12HP AC MOTOR K
DWYER 4025C 500 PSIG CAPSUHELIC DIFFERENTIAL PRESSURE G
MILWAUKEE VALVE 509, SWING CHECK VALVE, 1/4″ NPT, 125 P
WEED INSTRUMENT MODEL 733 DUCT AIR SENSOR 733PB-U-6 NE
VALENITE GAGING SYSTEMS TRANSDUCER TERMINAL STRIP BOARD
SICK POWER SUPPLY FOR CLV 200 OR CLV 400 BARCODE SYSTEM
GE FANUC SERIES 90-30 PROGRAMMABLE CONTROLLER STANDARD
WTC WELDING TECHNOLOGY AC WELD TIMER MODULE GA03-T15A
NUMATICS EDV-02 ELECTRONIC DRAIN VALVE, 110 VAC, 300 PS
ALLEN BRADLEY FLEX I/O INPUT MODULE 1794-IB16 SER. A N
ALLEN BRADLEY SIEMENS 460-415-380V 3-PHASE REACTOR 1131
ITW BALANCE ENGINEERING MEMORY CARD PCB GESMEM-12D 9602
SANYO DENKI TAPE READER 2702
ORIENTAL MOTOR 6W AC SPEED CONTROL MOTOR MSM206-402
SQUARE D EK-306-1 ELECTRICAL INTERLOCK FOR 60A SWITCH,
NUMATICS, 153SS415M, PNEUMATIC VALVE, 3/8″ NPT, 150 PSI
