一、国外PLC发展概况
PLC自问世以来，经过40多年的发展，在美、德、日等工业发达***已成为重要的产业之一。世界总销售额不断上升、生产厂家不断涌现、品种不断翻新。产量产值大幅度上升而价格则不断下降。
目前，世界上有200多个厂家生产PLC，较有名的：美国：AB通用电气、莫迪康公司；日本：三菱、富士、欧姆龙、松下电工等；德国：西门子公司；法国：TE 施耐德公司；韩国：三星、LG公司等。
二、技术发展动向
1. 产品规模向大、小两个方向发展
大： I/O点数达14336点、32位为微处理器、多CPU并行工作、大容量存储器、扫描
速度高速化。
小： 由整体结构向小型模块化结构发展，增加了配置的灵活性，降低了成本。
2. PLC在闭环过程控制中应用日益广泛
3. 不断加强通讯功能
4. 新器件和模块不断推出
***的PLC除了主要采用CPU以提高处理速度外，还有带处理器的EPROM或RAM的智能I/O模块、高速计数模块、远程I/O模块等专用化模块。
5. 编程工具丰富多样，功能不断提高，编程语言趋向标准化
有各种简单或复杂的编程器及编程软件，采用梯形图、功能图、语句表等编程语言，亦有***的PLC指令系统。
6. 发展容错技术
采用热备用或并行工作、多数表决的工作方式。
7.追求软硬件的标准化。
三、国内发展及应用概况
我国的PLC产品的研制和生产经历了三个阶段：顺序控制器（1973～1979）——一位处理器为主的工业控制器（1979～1985）——8位微处理器为主的可编程序控制器（1985以后）。在对外开放政策的推动下，国外PLC产品大量进入我国市场，一部分随成套设备进口。如宝钢一、二期工程就引进了500多套，还有咸阳显象管厂、秦皇岛煤码头、汽车厂等。现在，PLC在国内的各行各业也有了极大的应用，技术含量也越来越高。
170MCI00700 NEW SEALED Modicon Interbus-S Conn 170-MCI-...
ASBDAU204 NEW Modicon Compact Analog OUT AS-BDAU-204
140CPU67160 Used REfurbished Modicon CPU 140-CPU-671-60
ASBADU206 NEW Modicon Compact Analog Input AS-BADU-206
140CPU43412A Excellent Tested Modicon CPU 140-CPU-434-1..?.
ASBDEP220 Used Guaranteed Modicon Discreet Input AS-BDE...
140CPS11420 NEW Modicon AC Power Sply 140-CPS-114-20
140CRA93100 Modicon Quantum RIO Drop 140-CRA-931-00
490NRP95400 FACTORY NEW Modicon Fiber Repeater 490-NRP-...
Modsoft Compact Modicon Programming Software
140CPU53414A Used Excellent Modicon CPU 140-CPU-534-14A
ASBDEP216 Used Modicon 16 Discreet IN AS-BDEP-216
140DDO84300 Used Modicon DC Out Source 140-DDO-843-00
140DDI85300 TESTED and Guaranteed Excellent Modicon DC ...
ASB875002 TESTED EXCELLENT Modicon Analog INPUT Module ...
170AAI03000 TESTED and GUARANTEED Modicon Momentum Anal...
140CRP93200 Used TESTED Modicon RIO HEAD Module 140-CRP...
ASBDAU202 TESTED Modicon / Schneider Analog Output Modu...
TWDLCAA24DRF Modicon Schneider Telemecanique Twido Modu...
140CPU43412A NEW Sealed Modicon CPU 140-CPU-434-12A
ASBADU206 Used TESTED and GUARANTEED Modicon Compact An...
ASBDAU204 NEW ORIGINAL BOX Modicon Compact Analog OUT A...
PC-E984-265 NEW Modicon Compact CPU PCE984265
ASB875111 Modicon Analog Input Module AS-B875-111
AS-BDAP-204 NEW SEALED Modicon Compact Out ASBDAP204
140EHC20200 Used Modicon High Speed Ctr 140-EHC-202-00
Item title
140XTS00200 NEW Modicon Quantum Term 140-XTS-002-00
140DRA84000 NEW Modicon Relay OUT 140-DRA-840-00
140DDI36400 Used Modicon DC In Module 140-DDI-364-00
140NOE77101 Modicon NEW FACTORY SEALED Ethernet 140-NOE...
140DRA84000 NEW FACTORY SEALED Modicon Relay OUT 140-DR...
PCE984385 Used GUARANTEED Modicon Slot Mount CPU PC-E98...
140EHC20200 NEW Modicon High Speed Ctr 140-EHC-202-00
140DAI55300 NEW SEALED Modicon Quantum AC IN 140-DAI-55...
140XBP00600 Modicon Quantum 6 Slot Back 140-XBP-006-00
140CPU65150 NEW FACTORY Sealed Modicon CPU 140-CPU-651-...
170AMM09000 Used Tested Modicon Momentum 170-AMM-090-00
140DDO35300 NEW SEALED Modicon DC Output 140-DDO-353-00
140NOE77111 Modicon Excellent Ethernet 140-NOE-771-11
PC-A984-130 Used Modicon Compact CPU PCA984130
140CPU53414B Used Excellent Modicon CPU 140-CPU-534-14B
AS8535000 Used Modicon Connector AS-8535-000
PCE984685 Used FULLY TESTED AND GUARANTEED Modicon Slot...
140ACI04000 USED EXCELLENT Modicon Analog IN 140-ACI-04...
140***I03000 NEW Modicon Analog Input Module 140-***I-030...
170CPS11100 Modicon NEW Momen Pwr Sply 170-CPS-111-00
416NHM21200 Used Modicon PCMCIA MB+ Adap 416-NHM-212-00
140DRA84000 NEW Factory Box Modicon Relay OUT 140-DRA-8...
140ARI03000 Used Modicon RTD IN 8CH 140-ARI-030-00
TSXASZ200 TESTED Modicon Micro Analog Output Module TSX...
170XTS00200 Modicon Momentum Spring Type Terminal 170-X...
140CPS11100 Used Modicon Power Supply 140-CPS-111-00
490NRP25400 Modicon Fiber Line Drop Repeater 490-NRP-25...
140CPU42402 Used TESTED Modicon Quan CPU 140-CPU-424-02
TSXP573634 Excellent Modicon Unity Premium CPU TSX-P574...
140***O02000 Modicon Quantum Analog Out 140-***O-020-00
Item title
A***84A002 Perfect Modicon Controller Module AS-M84A-002
140ACO13000 NEW SEALED Modicon Analog OUT 140-ACO-130-0..?.
140DDI35310 NEW SEALED Modicon DC In 4x8 140-DDI-353-10
AS-BZAE-201 Used Modicon High Speed Counter ASBZAE201
170AAI14000 Modicon Momentum Analog Base 170-AAI-140-00
ASB875101 TESTED Modicon Analog INPUT Module AS-B875-10...
140CPS11420 Used Modicon AC Power Sply 140-CPS-114-20
170INT11000 NEW Modicon Momentum Interbus 170-INT-110-0..?.
AS-BDAP-204 Modicon Compact Out Module ASBDAP204
AS-P120-000 Used Modicon Power Sply ASP120000
170ADI34000 Modicon DC Discreet I/O Base 170-ADI-340-00
140ARI03010 Used Modicon RTD IN 8CH 140-ARI-030-10
AS-BDAP-209 Modicon Discreet Output Relay ASBDAP209
140CPS11100 NEW Modicon Power Supply 140-CPS-111-00
XVBC21 Brand New Telemecanique Stack Light Base&Cover
170ADI54050 TESTED AND GUARANTEED Modicon 120 VAC I/O B...
140NOE77110 Modicon Used Excellent Guaranteed Ethernet ...
140DDI35300 Used Modicon DC In 4x8 Sink 140-DDI-353-00
140CPS11410 New No Box Modicon Quantum 140-CPS-114-10
140CPS11420 NEW OPEN BOX Modicon AC Power Sply 140-CPS-...
140CPS12420 NEW FACTORY SEALED Modicon Power Supply 140...
140CRP93100 Used Modicon RIO HEAD Module 140-CRP-931-00
140DDI35300 New Open Modicon DC In 140-DDI-353-00
140ACI04000 NEW FACTORY SEALED Modicon Analog IN 140-AC...
TSXMBP100 BRAND NEW Modicon MB+ PCMCIA Card TSX MBP 100
140***I03000 Modicon Analog Input Module 140-***I-030-00
140DDI84100 FACTORY SEALED Modicon DC IN 140-DDI-841-00
140CPU53414B NEW SEALED Modicon CPU 140-CPU-534-14B
140NOE77101 Modicon Used Excellent Guaranteed Ethernet ...
140ATI03000 Used TESTED Modicon IN 8CH 140-ATI-030-00
ASBDAU204 NEW SEALED BOX Modicon Compact Analog OUT AS-...
140ESI06210 Used TESTED Modicon Quan ASCII 2 CH 140 ESI...
140CPS51100 NEW SEALED Modicon Power Supply 140-CPS-511...
140ACI03000 NEW SEALED Modicon Analog IN 140-ACI-030-00
140CHS11000 FULLY TESTED AND GUARANTEED Modicon S911 H...
140CPS21400 Modicon NEW SEALED Pwr Sply 140-CPS-214-00
TSXPSY1610 TESTED Modicon Premium Pwr Sply TSX-PSY-1610
140NOM21200 Modicon Used Network Option 140-NOM-212-00
TSXP575634 Modicon Unity Premium CPU TSX-P575634M
ASBDEP218 Used Modicon 16 Pt 115VAC AS-BDEP-218
TSXMBP100 Modicon MB+ PCMCIA Card TSX MBP 100
170AAI14000 NEW SEALED Modicon Analog 170-AAI-140-00
140DAO84210 Used Modicon Quan AC OUT 100 140-DAO-842-10
140AMM09000 TESTED Modicon Analog In/Out 140-AMM-090-00
PC-E984-265 BRAND NEW Modicon Compact CPU PCE984265
PM24038 4 Meg Centennial Linear Flash PC Card
PC-E984-245 Modicon / Schneider Compact CPU PCE984245
110CPU51201 Modicon Micro Controller 110-CPU-512-01
PCE984785 Excellent Modicon Slot Mount CPU PC-E984-785