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、。

（1）低档PLC

低档PLC具有逻辑运算、定时、计数、移位以及自诊断、监控等基本功能，还可有少量模拟量输入/输出、算术运算、数据传送和比较及通信等功能，主要用于逻辑控制、顺序控制或少量模拟量控制的单机控制系统。

HONEYWELL APT2000 CC-0-00 Conductivity Transmitter (NEW in BOX)
HONEYWELL AQ25242B / AQ25242B (BRAND NEW)
HONEYWELL AQ25244B / AQ25244B (BRAND NEW)
HONEYWELL AQ475A1004 / AQ475A1004 (NEW NO BOX)
HONEYWELL AR25BDN2050 / AR25BDN2050 (USED TESTED CLEANED)
Honeywell Assy 4DP7APXDH 511200 Fw Rev A DATA Highway I/F Control Board
Honeywell Assy no 51401642-150 E High Performance I/O Link Card 51401642150
Honeywell Assy No. 30752588-001 PLC Board Card 8KXI7 CMOS RAM
Honeywell Assy No. 51309175-001 Rev D2 For UDC6300 Digital Controller
Honeywell Assy No. 51309178-001 Rev A3  For UDC6300 Digital Controller
Honeywell Assy No. 51309178-001 Rev A3 For UDC6300 Digital Controller
HONEYWELL ATG-2PCA / ATG2PCA (USED TESTED CLEANED)
Honeywell Battery Backup Backplane 30734501-001 60 DAY WARRANTY!
HONEYWELL BEAM1224 / BEAM1224 (USED TESTED CLEANED)
HONEYWELL BF4CHM / BF4CHM (USED TESTED CLEANED)
HONEYWELL BF4MDC 60130571 HEDP-G 60130572-001 ACCURAY 085156-001 2-085155-001
HONEYWELL BPNL150B-001 INTERFACE CONTROL DISPLAY 60127728-002 BX2CP HEDPG
HONEYWELL BURNER CONTROL RM7800 M 1011,DYNAMIC R7847C1005 ,ST7800A1005, BY
HONEYWELL BURNER CONTROL RM7800 M 1011,DYNAMIC R7847C1005 ,ST7800A1039, BY
HONEYWELL BURNER CONTROL RM7840M1017,ST7800A1005,R7847C1005,Q7800A1005,EY
Honeywell Burner Control Ultraviolet Flame Amplifier ec7850 a 1122
HONEYWELL BXC4S / BXC4S (BRAND NEW)
HONEYWELL C072 / C072 (NEW IN BOX)
HONEYWELL C32211 / C32211 (NEW NO BOX)
Honeywell C6045D 1050 1 Air/Gas Pressure Switch C6045D10501 (Pack of 6)
HONEYWELL C7012A-1160 FLAME DETECTOR used tested shutter is working perfect
HONEYWELL C7012A-1160 FLAME DETECTOR used tested shutter is working perfect
HONEYWELL C7061A-1012 FLAME DETECTOR used tested shutter is working perfect
HONEYWELL C7061A-1012 FLAME DETECTOR used tested shutter is working perfect
Honeywell C7061A1020 UV Flame Detector C7061A1020 Free Expedited Shipping
HONEYWELL C-AF000 / CAF000 (NEW IN BOX)
HONEYWELL CARD DMA 4DP7AXDH 233(A) *NEW NO BOX*
HONEYWELL CC-PDIL01 / CCPDIL01 (USED TESTED CLEANED)
Honeywell CC-PDOB01 Digital Output 24V
Honeywell CC-PDOB01 P/N: 51405043-176 digital output 24V module
HONEYWELL CC-PFB401 / CCPFB401 (USED TESTED CLEANED)
HONEYWELL CC-PSV201 / CCPSV201 (USED TESTED CLEANED)
HONEYWELL CCR30-ISO-IRMS MODULE 65876983
HONEYWELL CCR30-ISO-IRMS MODULE 65876983 Type ELFD P/N: 65876983
HONEYWELL CCT722B / CCT722B (BRAND NEW)
HONEYWELL CC-TAIX01 / CCTAIX01 (USED TESTED CLEANED)
HONEYWELL CC-TAIX11 / CCTAIX11 (NEW IN BOX)
Honeywell CC-TDIL01 Digital Input Board 24v-dc Rev C2
Honeywell CC-TDOB01 I/O BOARD P/n: 51308371-175
Honeywell CC-TDOB01 I/O BOARD P/n: 51308371-175
Honeywell CC-TDOB01 I/O BOARD P/n: 51308371-175 New Unused
HONEYWELL CC-TFB401 51308309-175 NUPI
HONEYWELL CC-TFB402 / CCTFB402 (NEW IN BOX)
HONEYWELL CENTRA MCR 200 MCR200  MCR 200-62 MCR20062
HONEYWELL CENTRA MCR 200 MCR200 MCR 200-62 MCR20062
HONEYWELL CHG-120 / CHG120 (USED TESTED CLEANED)
HONEYWELL CHS5500WF6002 / CHS5500WF6002 (BRAND NEW)
HONEYWELL CLSB9T-BHP-C / CLSB9TBHPC (BRAND NEW)
HONEYWELL CLSXB4T / CLSXB4T (BRAND NEW)
HONEYWELL CLSXB9T-E1 / CLSXB9TE1 (BRAND NEW)
HONEYWELL CLSXE1A / CLSXE1A (BRAND NEW)
Honeywell Coke Feeder Circuit Board WFC1002 120V
Honeywell Conductivity Cell 04973-X01 Module PLC DCS Transmitter Transducer
Honeywell Conductivity Cell 04973-X01 Module PLC DCS Transmitter Transducer   
HONEYWELL CONTROL BOARD 30676602-001 *NEW IN BOX*
Honeywell Control Network Module 620-0038 new
Honeywell Controller XL50
Honeywell ControlNet Repeater Adapter TC-RPA002 NIB
HONEYWELL CP-5801 / CP5801 (USED TESTED CLEANED)
HONEYWELL CP-5802 / CP5802 (USED TESTED CLEANED)
HONEYWELL CP980E1060 / CP980E1060 (BRAND NEW)
HONEYWELL CP-EXPIO / CPEXPIO (NEW IN BOX)
HONEYWELL CP-EXPIO / CPEXPIO (NEW NO BOX)
Honeywell CP-EXPIO ComfortPoint BACnet DDC Solution CPEXPIO New
HONEYWELL CP-IPC / CPIPC (USED TESTED CLEANED)
HONEYWELL CP-SPC / CPSPC (NEW NO BOX)
HONEYWELL CP-SPC / CPSPC (USED TESTED CLEANED)
HONEYWELL C-STC61 / CSTC61 (NEW IN BOX)
HONEYWELL C-TCB YAMATAKE TERMINAL PANEL CONTROLLER FOR C-TCB20,30751315-001,DJ
Honeywell D254.DIN.110.US  Lamp Dimmer 01-9918
Honeywell D254.DIN.110.US Lamp Dimmer 01-9918
HONEYWELL D41997-01 / D4199701 (USED TESTED CLEANED)
Honeywell DC100-8002 Temperature Controller
HONEYWELL DC200C-2-00F-100000-0 UNIVERSAL DIGITAL CONTROLLER UDC2000 MINI PRO
HONEYWELL DC200E-0-210-1F0000-0 UNIVERSAL DIGITAL CONTROLLER UDC2000 MINI PRO
HONEYWELL DC230B-CE-0A-10-0000000-00-0 NSMP
HONEYWELL DC230B-CE-0A-10-0000000-E0-0 NSNP
HONEYWELL DC230B-TE-00-10-0000000-00-0 NSMP
HONEYWELL DC230B-TE-00-10-0000000-00-0 NSNP
HONEYWELL DC230L-EE-20-20-0A00000-00-0 TEMPERATURE CONTROLLER*NEW NO BOX*
HONEYWELL DC300E-E-000-20-BF00-0 TEMPERATURE CONTROLLER *USED*
HONEYWELL DC300E-E-000-22-000-0 TEMPERATURE CONTROLLER * NEW NO BOX *
HONEYWELL DC300E-E-2A0-22-0000-0 TEMPERATURE CONTROLLER  * NEW NO BOX *
HONEYWELL DC300E-E-2A0-22-0000-0 TEMPERATURE CONTROLLER * NEW NO BOX *
HONEYWELL DC300K-E-103-21-0A00-0 TEMPERATURE CONTROLLER * USED *
HONEYWELL DC300K-E-2A3-21-0A00-0 / DC300KE2A3210A000 (USED TESTED CLEANED)
Honeywell DC5062-0-0A00-200-00-0211 Ultra Pro Controller UDC5000 New
Honeywell DCP 25 Controller (Brand New)
Honeywell DCS PLC TC-CCN012 Net Interface Module Transducer Transmitter Meter
Honeywell DCS PLC TC-CCN012 Net Interface Module Transducer Transmitter Meter 
Honeywell DCS PLC TC-CCR013 Net Interface Module Transducer Transmitter Meter
Honeywell DCS PLC TC-CCR013 Net Interface Module Transducer Transmitter Meter 
HONEYWELL DIA-2020 / DIA2020 (USED)
Honeywell Digital Controller SDC 3-10PC Heater Control
Honeywell Digital Controller SDC 3-10PC Heater Controller
HONEYWELL DM106-0-B-00-A-R-1-00000-000-00 / DM1060B00AR10000000000 (USED TESTED
HONEYWELL DM106-0-B-00-A-R-1-00000-000-00 / DM1060B00AR10000000000 (USED TESTED
HONEYWELL DM106-0-B-00-A-R-1-00000-000-E0 / DM1060B00AR100000000E0 (USED TESTED
HONEYWELL DM106-0-B-00-A-R-1-00000-000-E0 / DM1060B00AR100000000E0 (USED TESTED
HONEYWELL DMCH02561110A1-35 / DMCH02561110A135 (USED TESTED CLEANED)
HONEYWELL DMX-PE42 / DMXPE42 (USED TESTED CLEANED)
HONEYWELL DPR51-2410-00 / DPR51241000 (USED TESTED CLEANED)
HONEYWELL DR4200GP2-00-GG00000 CHART RECORDER *USED*
HONEYWELL DR4300 DR4301-0000-B0100-0000-0000-U0-000_AS-PICTURED_GREAT DEAL_$$$!~
HONEYWELL DS06-105-DUS-LF / DS06105DUSLF (BRAND NEW)
HONEYWELL DS06-105-DUT-LF / DS06105DUTLF (BRAND NEW)
HONEYWELL DSP3956 / DSP3956 (BRAND NEW)
HONEYWELL E3DA / E3DA (BRAND NEW)
HONEYWELL E3DM / E3DM (BRAND NEW)
Honeywell E42009287-0642 Power Supply Board E420092870642
HONEYWELL EC7850 A 1080 BURNER CONTROL Digital Display
HONEYWELL EC7850 A 1080 BURNER CONTROL Digital Display
HONEYWELL EC-F9-NH3 / ECF9NH3 (USED TESTED CLEANED)
HONEYWELL EC-FX-NH3-LR / ECFXNH3LR (BRAND NEW)
Honeywell Echelon 1250 Router Model 40222
HONEYWELL EMD/DM/LGC/J/0-999F/SCT/N/0-10VDC / EMDDMLGCJ0999FSCTN010VDC (USED TES
HONEYWELL EMM-ST/N/01 / EMMSTN01 (USED TESTED CLEANED)
Honeywell EPDG 51401286-100 HDW J FW K Enhanced Peripheral Display Generator PLC
HONEYWELL EXD-AR20-3 / EXDAR203 (BRAND NEW)
Honeywell Expansion Module FF-SRE3081E _ FFSRE3081E _ 120V AC _ 50/60 HZ
HONEYWELL F300B2012 / F300B2012 (BRAND NEW)
HONEYWELL F300E1001 / F300E1001 (BRAND NEW)
HONEYWELL F300E1019 / F300E1019 (BRAND NEW)
HONEYWELL F300E1027 / F300E1027 (BRAND NEW)
HONEYWELL F56103101 / F56103101 (USED TESTED CLEANED)
Honeywell FC THERM BOARD 05428901 Rev. A
HONEYWELL FCPS-24FS6 / FCPS24FS6 (NEW IN BOX)
Honeywell FC-RUSIO3224 Remote Universal Safe I/O
HONEYWELL FC-TPSU-2430 / FCTPSU2430 (NEW IN BOX)
HONEYWELL FC-TSDI-1624 NUPI
HONEYWELL FE-MLS2E-5C / FEMLS2E5C (NEW NO BOX)
HONEYWELL FE-MLS2R-5C / FEMLS2R5C (NEW NO BOX)
HONEYWELL FE-MLSTR3 / FEMLSTR3 (NEW IN BOX)
HONEYWELL FE-TR3 / FETR3 (NEW IN BOX)
HONEYWELL FE-TR4-2 / FETR42 (NEW IN BOX)
HONEYWELL FE-TR5 / FETR5 (USED TESTED CLEANED)
HONEYWELL FF3-20-AC-03 / FF320AC03 (BRAND NEW)
HONEYWELL FFS-11-QD05 / FFS11QD05 (BRAND NEW)
HONEYWELL FF-SADL78RE / FFSADL78RE (USED TESTED CLEANED)
HONEYWELL FF-SB14E124-S2 / FFSB14E124S2 (USED)
HONEYWELL FF-SB14E14K-S2/3 / FFSB14E14KS23 (USED TESTED CLEANED)
HONEYWELL FF-SPR47TRG / FFSPR47TRG (USED TESTED CLEANED)
HONEYWELL FFSRO5936E / FFSRO5936E (NEW IN BOX)
HONEYWELL FF-SYA30048Q2 / FFSYA30048Q2 (USED)
Honeywell Flame detectors Ultraviolet C7012E 1104 New no box
HONEYWELL FMA112AV / FMA112AV (NEW IN BOX)
HONEYWELL FMF111-AV / FMF111AV (USED TESTED CLEANED)
Honeywell FSC 10002/1/2 Run Stop with Key Selector Module
HONEYWELL FSC 10006/2/1 Diagnostic and battery module (DBM)
HONEYWELL FSC 10105/2/1 Fail-safe HD analog input module (24 Vdc, 16 channels)
HONEYWELL FSC 10208/1/1 Relay output module (contacts, 12 channels)
HONEYWELL FSD-751PL / FSD751PL (USED TESTED CLEANED)
HONEYWELL FSD-751RPL / FSD751RPL (USED TESTED CLEANED)
HONEYWELL FSP1535 / FSP1535 (NEW NO BOX)
HONEYWELL G3L-CUEA PRAGRAMMABLE LOGIC CONTROLLER MODULE - FREE SHIPPING -
HONEYWELL GKDB2K2 / GKDB2K2 (BRAND NEW)
HONEYWELL GKFE16LXA2 / GKFE16LXA2 (BRAND NEW)
HONEYWELL GKLA14P6A2-FW / GKLA14P6A2FW (NEW NO BOX)
HONEYWELL GKLA-40F1C2-F05-C / GKLA40F1C2F05C (USED TESTED CLEANED)
HONEYWELL GKLG44LXS2 / GKLG44LXS2 (BRAND NEW)
HONEYWELL GKRA-2K1A2-F04 / GKRA2K1A2F04 (USED TESTED CLEANED)
HONEYWELL GKRA40F1C2-F05-C / GKRA40F1C2F05C (USED TESTED CLEANED)
HONEYWELL GKRA-40L6A2-F05 / GKRA40L6A2F05 (NEW IN BOX)
HONEYWELL GMC-755P-G CAMERA
HONEYWELL GMS10-18C / GMS1018C (BRAND NEW)
HONEYWELL GSXA22A1A / GSXA22A1A (BRAND NEW)
HONEYWELL H4D5S2 / H4D5S2 (NEW IN BOX)
HONEYWELL HB546-BVSR-DKSN-15B2-000 / HB546BVSRDKSN15B2000 (NEW NO BOX)
HONEYWELL HC 900 CONTROLLER  900R12-000112 (12 I/O SLOT RACK )
HONEYWELL HC 900 CONTROLLER 900R12-000112 (12 I/O SLOT RACK )
HONEYWELL HC900 10420F-0021 PLC OPERATOR INTERFACE 24VDC
HONEYWELL HC900 Controller 900C32-0244-00 C30 CPU 72-1
Honeywell hc900 controller 900psm-0001 module
Honeywell hc900 controller 900rr0-0001 plc rack
HONEYWELL HC900 CONTROLLER C30 CPU 900C32-0124-00 Upgraded to Revision 4.406
HONEYWELL HC900 CONTROLLER C30 CPU 900C32-0244-00 Upgraded to Revision 4.406
Honeywell HC900 Controller Open Box Brand NEW
HONEYWELL HFM5100-EAM / HFM5100EAM (NEW IN BOX)
HONEYWELL HFM5100-FAM / HFM5100FAM (NEW IN BOX)
HONEYWELL HMR3300 DEMO / HMR3300DEMO (BRAND NEW)
Honeywell Honeywell DCS 51304485-150 MC-PDIX02 DI IOP
HONEYWELL HPFF8CM / HPFF8CM (NEW IN BOX)
HONEYWELL HRGX161 / HRGX161 (USED TESTED CLEANED)
HONEYWELL HVFD2D3B0040 / HVFD2D3B0040 (BRAND NEW)
HONEYWELL HVFD2D3B0050 / HVFD2D3B0050 (BRAND NEW)
HONEYWELL HVFD2D3C0040E2 / HVFD2D3C0040E2 (BRAND NEW)
HONEYWELL HVFD2D3C0050 / HVFD2D3C0050 (BRAND NEW)
HONEYWELL HVFD2D3C0050E2 / HVFD2D3C0050E2 (BRAND NEW)
HONEYWELL HVFD2D3C0075E2 / HVFD2D3C0075E2 (BRAND NEW)
HONEYWELL HVFD2D3F0030 / HVFD2D3F0030 (BRAND NEW)
HONEYWELL HVFD2D3F0050 / HVFD2D3F0050 (BRAND NEW)
HONEYWELL HVFDSD3A0007G100A / HVFDSD3A0007G100A (BRAND NEW)
HONEYWELL HVFDSD3A0010G100A / HVFDSD3A0010G100A (BRAND NEW)
HONEYWELL HVFDSD3A0015G100A / HVFDSD3A0015G100A (BRAND NEW)
HONEYWELL HVFDSD3C0015G100A / HVFDSD3C0015G100A (BRAND NEW)
HONEYWELL HVFDSD3C0020G100A / HVFDSD3C0020G100A (BRAND NEW)
HONEYWELL HVFDSD3C0030G100A / HVFDSD3C0030G100A (BRAND NEW)
Honeywell I/O Ipc 621-9937
HONEYWELL I/O LINK EXTENDER 51304532-100 REV
HONEYWELL I/O LINK EXTENDER 51304532-100 REV
Honeywell I/O Rack Power Supply, 621-9933C (US)
HONEYWELL IAQ-DAV-TRH-D / IAQDAVTRHD (BRAND NEW)
HONEYWELL IAQ-DNC-TRH-D / IAQDNCTRHD (BRAND NEW)
HONEYWELL IAQ-DNV-D / IAQDNVD (BRAND NEW)
HONEYWELL ICM-4 / ICM4 (NEW IN BOX)
HONEYWELL ICM-4 / ICM4 (NEW NO BOX)
HONEYWELL INPUT/OUTPUT LINK MODULE 51201557-350 REV. F
Honeywell io link extender c en p2011045 dc br12w23 p0903 assy no 5130441
HONEYWELL IO-16-485 / IO16485 (NEW IN BOX)
HONEYWELL IO-16-REM-H / IO16REMH (BRAND NEW)
HONEYWELL IO-R-16 / IOR16 (NEW IN BOX)
Honeywell IPC 1000 IPC1000 Programmable Temperature Controller
Honeywell Ipc 620-16 Control Processor Module 620-1633C
Honeywell IPC 620-16 control processor modules 620-1633C
Honeywell Ipc 621 I/O Rack Power Supply 621-9934
Honeywell IPC 621 System Diagnostic Module 621-0004 SDM
Honeywell IPC 621-6551 Output Module 24v Unused Original Box
Honeywell IPC Automation Systems Processor Power Supply Module 620-0083
Honeywell IPC Automation Systems Processor Power Supply Module 620-0083
Honeywell Isolated Analog Input 321-0022R, 321-0022 R
HONEYWELL ISSC 300-LC2A/2 PROCESSOR CARD 300-LC2A-2 300LC2A2 REPAIRED
HONEYWELL IZM-8 / IZM8 (NEW IN BOX)
HONEYWELL J-HCX00 / JHCX00 (NEW NO BOX)
HONEYWELL J-PF200 / JPF200 (USED TESTED CLEANED)
Honeywell Kat CNC Axis, 622-3020A (US)
Honeywell Kat CNC CPU, 622-3010 (US)
HONEYWELL KDM-R2 / KDMR2 (USED TESTED CLEANED)