PLC控制系统中的干扰是一个十分复杂的问题，因此在抗干扰设计中应综合考虑各方面的因素，合理有效地抑制抗干扰，对有些干扰情况还需做具体分析，采取对症下药的方法，才能够使PLC控制系统正常工作。
下面我们着重介绍三菱公司的FX2N系列产品的一些编程元件及其功能。
FX系列产品，它内部的编程元件，也就是支持该机型编程语言的软元件，按通俗叫法分别称为继电器、定时器、计数器等，但它们与真实元件有很大的差别，一般称它们为“软继电器”。这些编程用的继电器，它的工作线圈没有工作电压等级、功耗大小和电磁惯性等问题；触点没有数量限制、没有机械磨损和电蚀等问题。它在不同的指令操作下，其工作状态可以无记忆，也可以有记忆，还可以作脉冲数字元件使用。一般情况下，X代表输入继电器，Y代表输出继电器，M代表辅助继电器，SPM代表专用辅助继电器，T代表定时器，C代表计数器，S代表状态继电器，D代表数据寄存器，MOV代表传输等。
GE Flex-A-Plug FVK366R Busway Switch 600 A Bus Fusible
Cutler-Hammer Sz Size 5 MCCB fits Siemens/Furnas MCC
Bolt Loc Bolted Pressure Switch VL 3612 G5 3000 Amp Gnd
ASCO 600 A Amp Transfer Switch ATS E436360097XC 480V
Micro Motion DL200S227SU Mass Flow Sensor MicroMotion
Westinghouse SPB 100 Pow-R Breaker SPB100 1600 Amp A
GE General Electric 1200 Amp 1200A A THKR4612GB Breaker
GE Circuit Breaker TS253F 2000 Amp 2000A A 2000Amp Trip
GE Circuit Breaker TS203F 2000 Amp 2000A A 2000Amp Trip
Siemens SMD69800ANGT SMD SMD6 800 Amp 800A A Sensitrip3
Allis-Chalmers LA-3000 3000 Amp A Air Circuit Breaker
Square D I-Line LX LXI36400 I-Limiter 400 Amp 400A A
ABB 1600 Amp Type LKE-16 LKE16 MPS-5 MPS5 Air Breaker
Dynamatic Eddy Curr. Clutch AT-441000-4041 90 DC 100HP
Hitran 280 kVA 575 Delta / 460 Y/ 266 3ph 280kVA 460Y
Sick PLS101-312 Photoelectric Proximity Safety Laser
Modicon PC-E984-785 Programmable Controller PC-E984785
Allen Bradley 150-A135NBD SMC Plus 100HP Soft Start
Westinghouse DS-632 DS632 3200 Amp Amptector I – A LS
Eaton Cutler Hammer 400 Amp Bus Fusible Switch P3F365RN
GE General Electric 3000 Amp Spectra End Tap Box 3P 4W
Siemens RL-1600 RL 1600 Amp Static Trip III RMS LSIG
Bolt Loc Bolted Pressure Switch VL 3612 G5 3000 Amp Gnd
ABB MultiDrive Multi Drive ACN684-0375-50000030A905 NEW
GE Transformer 275kVA 460/230Y/133 V 275 kVA 3 PH 230 Y
Cutler Hammer Westinghouse HLD3400 400 Amp HLD3400T107W
With Digitrip Optim 1050 Prog. trip unit and Top Lugs
Square D 8538 Sz Size 5 Combination Starter Stainless S
Square D 8538 Sz Size 5 Combination Starter Stainless
ITE Gould Imperial 5600 5640 Sz 5 Fused MCC Bucket 270A
Siemens SHMD69800AH SHMD 800 Amp 800A A Sensitrip 3 III
Merlin Gerin CK800HH Square D CKHEL36808LI 800 Amp 800A
Square D Breaker MXF36800G 800Amp 800 A Electronic Trip
GE AKR-6D-50 1600 A Amp Air Breaker NO TRIP 635V
Bently Nevada 3300/35 6 Ch Temperature Monitor 330035
Cutler Hammer Eaton Breaker LDC3600F LT3600T 600 Amp A
Cutler Hammer Eaton Breaker LDC3600 LT3600T 600 Amp A
FSI FSP-1000-CS filter bag vessel Carbon Steel CS 5″
GE AKR-7D-30S 800 A Amp Air Breaker RMS-9 TS20LIT1 LI
Reliance Electric Motor 150 HP 1785 RPM Efficient 447U
GE Power Break Switch TCYY7625E1C 2500 Amp 2500A A
Klockner-Moeller NZM12V-630 w/Trip ZM12V-630 600 A Amp
ITE Circuit Breaker CP3 B160 Type ET 1600 Amp Trip
Square D I Line ME ME36400LIG ME36400 400 Amp Frame
Square D Schneider Masterpact NW12L 1200 A CRADLE NIB
ASCO 600 A Amp Transfer Switch 277 / 480 V 940360099C
Cutler Hammer Westinghouse 600 Amp A HLD3600T107W
