PLC是以微处理器为基础，综合了计算机技术、自动控制技术和通信技术，用面向控制过程面向用户的“自然语言”编程，适应工业环境，简单易懂、操作方便、可靠性高的新一代通用工业控制装置。PLC是在继电器顺序控制基础上发展起来的以微处理器为核心的通用自动控制装置。

可编程序控制器是一种数字运算操作电子系统，专为在工业环境下应用而设计。它采用了可编程序的存储器，用来在其内部存储执行逻辑运算、顺序控制、定时、计数和算术运算等操作指令，并通过数字的、模拟的输入和输出，控制各种类型的机械或生产过程。可编程序控制器及其有关的外围设备，都应按易于与工业控制系统形成一个整体、易于扩充其功能的原则设计。

PLC产品种类繁多，其规格和性能也各不相同。对于PLC，通常根据其结构形式的不同、功能的差异和I/O点数的多少等进行大致分类。

按结构形式分类

根据PLC的结构形式，可将PLC分为整体式和模块式两类。

整体式PLC

整体式PLC是将电源、CPU、I/O接口等部件都集中装在一个机箱内，如图所示。具有结构紧凑、体积小、价格低的特点。小型PLC一般采用这种整体式结构。整体式PLC由不同I/O点数的基本单元（又称主机）和扩展单元组成，基本单元内有CPU、I/O接口、与I/O扩展单元相连的扩展口以及与编程器或EPROM写入器相连的接口等；扩展单元内只有I/O和电源等，而没有CPU。基本单元和扩展单元之间一般用扁平电缆连接。整体式PLC一般还可配备特殊功能单元，如模拟量单元、位置控制单元等，使其功能得以扩展。

2）模块式PLC

模块式PLC将PLC的各组成部分分别做成若干个单独的模块，如CPU模块、I/O模块、电源模块（有的含在CPU模块中）以及各种功能模块。模块式PLC由框架或基板和各种模块组成，模块装在框架或基板的插座上，如图所示。这种模块式PLC的特点是配置灵活，可根据需要选配不同规模的系统，而且装配方便，便于扩展和维修。大、中型PLC一般采用模块式结构。

还有一些PLC将整体式和模块式的特点结合起来，构成所谓的叠装式PLC。叠装式PLC的CPU、电源、I/O接口等也是各自独立的模块，但它们之间是靠电缆进行连接的，并且各模块可以一层层地叠装。这样，不但系统可以灵活配置，还可做得体积小巧。

2.2.按功能分类

根据PLC的功能不同，可将PLC分为低档、中档、。

Fanuc A06B-6078-H222 #H500 Spindle Amp Module,Ser A,  , WARRANTY
Fanuc A06B-3071-K203 A06B3071K203 Connector 3P CX1A CX4 K3 K6 K7
Fanuc A06B-3071-K203 A06B3071K203 Connector 3P CX1A CX4 K3 K6 K7
FANUC A06B-0652-B002 SERVO MOTOR DC 20M 4X RESOLVER **repair evaluation**
FANUC A06B-0652-B002 SERVO MOTOR DC 20M 4X RESOLVER **repair evaluation**
FANUC A06B-0601-B031   A06B0601B031
FANUC A06B-0522-B041 MODEL 1-0? W/ FANUC A290-0521-V541 PULSE ENCODER
FANUC A06B-0502-B202#7000 AC SERVO MOTOR, 3PHASE, 8POLE, TRQ. (STALL):,  *
Fanuc A06B-0116-B804 servo motor
Fanuc A05B-2301-C300 Teach Pendant, WIN-10484-SH,  , Warranty
Fanuc A02B-0319-C243 Operator's Panel Interface,  , WARRANTY
FANUC A02B-0236-K313   A02B0236K313 CONNECTOR 20PIN CM68 CM69 
FANUC A02B-0120-K324 AMP 3 PIN FEMALE X TYPE CABLE CONNECTOR SOLDER 
Fanuc 9" O-M HI-FI MDI/CRT Operator's Panel, A02B-0092-C052,  , WARRANTY
Fanuc 7.5 kVA Transformer, A80L-0026-0002 #A-01,  , WARRANTY
Fanuc 6M MDI/CRT Display Unit, A02B-0060-C034, With Monitor,  , WARRANTY
Fanuc 6 Axis Servo Amplifier Module, A06B-6076-H101, Ser A,  , WARRANTY
Fanuc 5/6 Axis Control Circuit Board, A16B-2200-0800 / 08B,  , WARRANTY
FANUC 4003-T234 CONNECTOR CABLE
Fanuc 3S/12000 AC Spindle Motor, # A06B-0753-B394 #3000,  , CRACKED PLASTIC
Fanuc 30M DC Servo Motor, A06B-0653-B011 (2000M),  , WARRANTY
Fanuc 21-T CRT Unit, # A02B-0210-C111,  , WARRANTY
Fanuc 21-M CRT Unit, # A02B-0210-C111,  , WARRANTY
Fanuc 2-0S A06B-0310-B351 AC 3 Phase 8 Pole Servo Motor w A290-0521-V581 Encoder
Fanuc 20M DC Servo Motor, A06B-0652-B212 (2500M),  , WARRANTY
FANUC 2.830" INNER DIAMETER, GEAR J12 A290-7216-X212 * *
Fanuc 18-TC 6 Slot Rack, A02B-0228-B503,  , WARRANTY
Fanuc 15-M CRT/MDI Control Panel Display Unit, A02B-0094-C021,  , WARRANTY(3)
Fanuc 15-M CRT/MDI Control Panel Display Unit, A02B-0094-C021,  , WARRANTY(2)
Fanuc 1-4 Axes Circuit Board, A16B-2200-0390 / 11B,  , WARRANTY
Fanuc 11 Series ROM/RAM PC Board, A16B-1211-0291 / 03A,  , WARRANTY
Fanuc 10M DC Servo Motor, A06B-0651-B211 (2000M),  , Warranty
Fanuc 10M DC Servo Motor, A06B-0651-B011 (2000M), Date: 04.09,  , WARRANTY
Fanuc 10.5" Mono 160iM Controller, 16iM-MCU20648-001R00,  , WARRANTY
Fanuc 1 / 2 Axis PC Board, # A16B-1212-0501 / 01,  , WARRANTY
Fanuc 0-Mate T MDI/CRT Unit, # A02B-0096-C043, O-Mate T,  , WARRANTY
Fanuc / General Numeric #2 AC Spindle Motor, # A06B-1002-B600 #2000,  
Fanuc .20 Upper Wire EDM Diamond Guide, A290-8021-X765
Fanuc .20 Lower Wire EDM Diamond Guide, A290-8021-X775
Fanuc .20 Lower Wire EDM Diamond Guide, A290-8021-X775
Fanuc #a22/3000 AC Sservo Motor, # A06B-0148-B188,  , WARRANTY
Fanuc #a22/2000 AC Servo Motor, # A06B-0147-B176,  , WARRANTY
Fanuc #a22/2000 AC Servo Motor, # A06B-0147-B176, 2000 RPM,  , Warranty
Fanuc #a22/2000 AC Servo Motor, # A06B-0147-B176 #7000,  , WARRANTY, Plastic
Fanuc #8 AC Spindle Motor, # A06B-1008-B102, 7.5/11 kW,  , WARRANTY
Fanuc #8 AC Spindle Motor, # A06B-1008-B100,  , WARRANTY
Fanuc #8 AC Spindle Motor, # A06B-1008-B100, Flange Mount,  , WARRANTY
Fanuc #2 AC Spindle Motor, # A06B-1002-B100, Flange Mount,  , Warranty
Fanuc #2 AC Spindle Motor, # A06B-1002-B100, Flange Mount, (2)  , Warranty
Fanuc # A6/2000 AC Servo Motor, # A06B-0127-B076,  , WARRANTY
Fanuc # A6/2000 AC Servo Motor, # A06B-0127-B076 #7000,  , WARRANTY
Fanuc # A12/2000 AC Servo Motor, # A06B-0142-B075-R,  , WARRANTY
Fanuc # A12/2000 AC Servo Motor, # A06B-0142-B075,  , WARRANTY
Fanuc # 8 / 8000 AC Spindle Motor, # A06B-0855-B102 / 3000-R, (2)  , AS IS
Fanuc # 8 / 8000 AC Spindle Motor, # A06B-0855-B102 #3000,  , WARRANTY
Fanuc # 3/2000 Pulse AC Servo Motor, # A06B-0121-B075,  , WARRANTY
Fanuc # 3 AC Spindle Motor, # A06B-1003-B100, 1500/6000 RPM, (8)  , WARRANTY
Fanuc # 3 AC Spindle Motor, # A06B-1003-B100, (2)  , WARRANTY
Fanuc # 20S AC Servo Motor, # A06B-0505-B205,  , WARRANTY
Fanuc # 20S AC Servo Motor, # A06B-0502-B851,  , WARRANTY
Fanuc # 20S AC Servo Motor, # A06B-0502-B756, WARRANTY
Fanuc # 20S AC Servo Motor, # A06B-0502-B006 #7000,  , WARRANTY
Fanuc # 20 AC Servo Motor, # A06B-0502-B243, 2000 RPM,  , WARRANTY
Fanuc # 10M DC Servo Motor, A06B-0851-B005, 165 V,  , WARRANTY
Fanuc # 0S AC Servo Motor, # A06B-0313-B002 #7000, 2000 RPM, Mfg'd: 11.12,  
Fanuc # 0S AC Servo Motor, # A06B-0313-B001, 2000 RPM, W/ Encoder,   Warranty
Factory Sealed SIEMENS SERVO MOTOR 1FK7032-5AF71-1SB5-Z   Factory Sealed
Factory Sealed SIEMENS SERVO MOTOR 1FK7022-5AF71-1SB5-Z   Factory Sealed
Ettco ATU-4 Lead Screw Tapping Machine, 3.5 HP Motor, NICE UNIT,  , WARRANTY
Etamic Opticline Optical Shaft Measuring Base, # CSZ SP, E401331,  , WARRANTY
Etamic Opticline Optical Shaft Measuring Base, # CSZ SP, CSZ 800,  , WARRANTY
Escort Memory Systems Passive Conveyor Reader/Writer, HMS827-04, HMS827,  
ESA NSK Servo Driver Unit, ESA-J1003A25-21,  , WARRANTY
ESA NSK Servo Driver Unit, ESA-J1003A23-21,  , WARRANTY
ESA NSK Servo Driver Unit, ESA-J1003A23-11,  , WARRANTY
Erickson Tool Company Air Speed Indexer, Model# 600,  , WARRANTY
Entrelec 10-121-12 24V AC or DC Relay Interface ABB RB 122 AV RB122AV 10
Emerson Brushless AC Servo Drive, # LX-700, 180031-01,  , WARRANTY
Emerson Brushless AC Servo Drive, # LX-1100, P/N 960154-02,  , WARRANTY
Emerson 20 HP Energy Efficient Motor, U20E1D, AF18, Refurbished, WARRANTY
Electro-Craft Servo Motor, # S-3016-N-H00AX, 7-94740,  , WARRANTY
Electro-Craft Servo Motor, # F-4075-R-H00AA, 2146-01-809,  , WARRANTY
ELECTRICAL CONTACTOR AB ALLEN BRADLEY ALLEN BRADLEY 100-A24ND3 SERIES C TESTED 
ELECTRICAL CONTACTOR AB ALLEN BRADLEY ALLEN BRADLEY 100-A12ND3 SERIES B TESTED 
Egis Hydrel 2 Axis Hydraulic Slide Arm, Toolchanger Swing Arm, B 215, WARRANTY
Edo-Aire Directional Gyro Indicator P/N C661075-0104 S/N 92912D M/N 4000B-12
EATON/CUTLER-HAMMER AE56DN0 SERIES C1 REVERSING STARTER