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、。

IRB6400/M98 ABB SERVO MOTORS REMANUFACTURED
IRB6400/M97 ABB ROBOTIC COMPONENTS REMANUFACTURED
Hartmann & Braun ABB Freelance 2000 DCP 10 P37211-4-0338701  F6.02.8 CPU Module
Hartmann & Braun ABB Freelance 2000 CPU DCP10 OVP
Fanuc S430iw Robot with RJ3 control system
Fanuc S430 robot, Fanuc Robot, Welding robot, ABB robot, Fanuc R2000
Fanuc S430 iw robot, Fanuc Robot, Fanuc RJ3 Control, ABB robot, Nachi Robot
Fanuc Robot, Welding robot, robot, Fanuc R2000,  Robot, Fanuc 430 robot, ABB
Fanuc M-6iB Robot w/ RJ3iB Control 2005 TESTED VIDEO Abb Motoman Kuka Nachi
Fanuc M-16iB/20 Robot System w/ RJ3iB Control 10,108 Hr Abb Motoman Kuka Nachi
Fanuc Linear 7th Axis Robot Transport Units 49'&13' Travel,Abb,Motoman,Kuka
Fanuc ArcMate 100i Welding Robot w/ RJ3 Control 11,000 HRS Abb Motoman Kuka
EMI 3000A 480Y277VAC Main-Tie w/ ABB SACE E3S-A 32 Circuit Breakers w/ 2500A Trp
E3S-A32 Circuit Breaker PR122/P-LSIG ABB SACE 3200A 
Cutler Hammer/ABB 3750/5000KVA 13,800-480Y/277 Dry Transber
Bula MR 250.5 - ABB IRB2000M93A 6 Axis Robot w/ Control Console/ Pendant / Cell
ALLEN BRADLEY 1326AB-B530E-21-Z13  1326ABB530E21Z13
ABB WESTINGHOUSE 3PH 13800-4160/2400V 750KVA SUBSTATION TRANSFORMER TYPE RSL
ABB TurboTrol Rack Power Distribution Breaker Panel 2 Modules and Breakers
ABB TurboTrol Rack 7 Modules
ABB TurboTrol Rack 13 Modules
ABB Teach Pendant 3HNA010906-001 , Refurbished with 90 Days Warranty.
ABB STROMBERG / ALLEN BRADLEY 500 HP Drive SAFUI 460F460 460 KVA MAKE OFFER!
ABB SK828086-AF CONTACTOR EHDB960C2P-1L * IN A BOX*
ABB SACE S8, 2000A Circuit Breaker with PR212/P Trip Module in a 3R Outside Case
ABB SACE S8 S8V-D Molded Case
ABB SACE S8 S8V 1600a Circuit Breaker LSI Functions Fixed Mount S8V1600
ABB SACE Emax E6 4000 Amp SACE E6H-A 40 PR123/P-LSIG kA 85 Int Circuit Breaker
ABB SACE E4 3200 Amp Circuit Breaker
ABB S4C+ IRB 1400 robot welding cell Flex Arc U with dual work stations
ABB S4C S4C+ robot 500C Flexarc welding cell HOOD and venting system included
ABB S4C IRB1400 robot 250L and 750L welding cell MUST SEE !!!! Flexarc dual L
ABB ROBOTICS SERVO MOTOR 3HAC10543-1 REV 2_280912298E_TS2640N141E172 REFURBISHED
ABB ROBOTICS ROBOTIC ARM IRB 2400 M2000 W/ CONTROLLER S4CPLUS M2000, 24-29190
ABB robot, ABB, ABB Robotics, Welding Robot, Fanuc Robot, Nachi Robot
ABB Robot, ABB 6400 M97 robot, Welding robot, ABB, Fanuc, Robot,Motoman, Nachi
ABB Robot, ABB 2400 robot, Welding robot, Fanuc Robot,  Robot, ABB M98
ABB Robot, ABB 2400 robot, Welding robot, Fanuc Robot,  robot
ABB Robot, ABB 2400 robot, Welding robot, Fanuc Robot, Nachi Robot,  Robot
ABB Robot, ABB 1400 robot, Welding robot, ABB S4C controls system, Fanuc Robot,
ABB Robot, ABB 140 robot, Welding robot, Fanuc Robot, Nachi Robot, Motoman Robot
ABB Robot with control panel
ABB Robot S4C+ IRB6600 2.55 meter arm 225kg IRB 6600 S4C+ robot abb
ABB robot S4C+ IRB6400R 3.0 meter arm 100kg IRB6400 S4C
ABB robot S4C+ IRB4400 60KG
ABB robot S4C+ IRB2400 16KG
ABB robot S4C S4C+ IRC5 IRB7600 400KG
ABB robot S4C S4C+ IRB1400 Flexarc 250R welding cell Positioner
ABB Robot Main Computer DSQC 361 BOARD SCHEDA 3HAC0373-1
ABB robot IRC5 S4C+ IRB6600
ABB Robot DSQC 345D RECTIFIER DC3 3HAB8101-4
ABB Robot DSQC 344 INTERBUS S SLAVE MASTER BOARD SCHEDA 3HAB7686-1
ABB Robot DSQC 324 BOARD SCHEDA 16 MB 3HAB5957-1
ABB Robot DSQC 236D SERVO DRIVE UNIT BOARD SCHEDA 3HAB2207-1
ABB Robot CONNECTOR BOARDS SCHEDA 3HNE 06466-1
ABB ROBOT ARM IRB7600/400-LONG ARM M2000, 76-20147 100403
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER M2000, 76-20164 100344
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER M2000, 76-20163 100343
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER M2000, 76-20159 100442
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER M2000, 76-20150 100406
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER M2000, 76-2015?, LABEL 100453
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER M2000, 76-20148 100399
ABB ROBOT ARM IRB7600/400-2.55 W/ CONTROLLER IRB7600 M2000
ABB ROBOT ARM IRB7600 /400-LONG ARM W/ CONTROLLER M2000, 76-20149 100014
ABB ROBOT ARM IRB6400R/3.0-100 W/ CONTROLLER M2000, 64-22527 100186
ABB ROBOT ARM IRB6400R/3.0-100 W/ CONTROLLER M2000, 64-22526 100220
ABB ROBOT ARM IRB6400R/3.0-100 W/ CONTROLLER IRB6400RM2000
ABB ROBOT ARM IRB6400R/2.8-200 W/ CONTROLLER M2000, 64-21488 100188
ABB ROBOT ARM IRB6400R/2.8-150 W/ CONTROLLER M2000, 64-22716 100163
ABB ROBOT ARM IRB6400R/2.8-150 W/ CONTROLLER IRB6400RM2000
ABB ROBOT ARM IRB6400R/2.5-150 W/ CONTROLLER M2000, 64-22736 100171
ABB ROBOT ARM IRB6400R/2.5-150 W/ CONTROLLER IRB6400RM2000
ABB ROBOT ARM IRB6400R/1.5-150 W/ CONTROLLER M2000, 64-22659 100216
ABB Robot 6600 M2000 175 S4C+ Robotic Cell Torque Laser Vision, clean Industrial
ABB Robobell RB 1000 HIGH FLOW ATOMIZER diametro coppa 4 cm
ABB Process Analytics Vista ll 2000 Gas Chromatograph M9~ 2063WVS
ABB Power Switchgear 4800 Volt W/ ABB Power Circuit Breaker 1200 Amp 4.76 KV
ABB Power Generation VKS93 Testing Device w/ all cabling and Manuals
ABB Power Circuit Breaker - Type 15-GHK-500 - 15KV Max - 1200 Amp - EO/DO
ABB PM866 3BSE050200R1 AC 800M DCS CONTROL MODULE
ABB PHCBR30000000 HARMONY BRIDGE CONTROLLER * IN A BOX*
ABB PFV1-101 POWER SUPPLY PFV1101 YM110001SP
ABB NEMA 1 1500 KVA 3PH CAST COIL TRANSFORMER ABB510911
Abb Motoman Kuka Nachi
ABB KP-40 KP40 4000 Amp 4000A Air Breaker MPS-C 2000
ABB K-Line Power Circuit Breaker K1600 K1600M 
ABB K-line K3000S power air circuit breaker
ABB IRB6600 ROBOT with S4C+ controller
ABB IRB6600 Robot & S4C+ Controller, Refurbished, Tested, With 90 Days Warranty
ABB IRB6400R M2000 ROBOT S4C+ CONTROLLER REFURBISHED w. WARRANTY
ABB IRB6400 ROBOT S4C M97 CONTROLLER REFURBISHED w. WARRANTY
ABB IRB6400 M98 Wrist Assembly W/ Siemens Motors 1FK6083-6AZ21-9229-2S02
ABB IRB340 ROBOT WITH S4C+ CONTROLLER FLEXPICKER
ABB IRB Robot 6600 M2000 S4C+ Control 2.8 Clean Industrial Robotic