底板或机架:
大多数模块式PLC使用底板或机架，其作用是:电气上，实现各模块间的联系，使能访问底板上的所有模块，机械上，实现各模块间的连接，使各模块构成一个整体。
五、PLC的外部设备
外部设备是PLC系统不可分割的一部分，它有四大类
1.编程设备:有简易编程器和智能图形编程器，用于编程、对系统作一些设定、监控PLC及PLC所控制的系统的工作状况。编程器是PLC开发应用、监测运行、检查维护不可缺少的器件，但它不直接参与现场控制运行。
2.监控设备:有数据监视器和图形监视器。直接监视数据或通过画面监视数据。
3.存储设备:有存储卡、存储磁带、软磁盘或只读存储器，用于性地存储用户数据，使用户程序不丢失，如EPROM、EEPROM写入器等。
4.输入输出设备:用于接收信号或输出信号，一般有条码读人器，输入模拟量的电位器，打印机等。
六、PLC的通信联网
PLC具有通信联网的功能，它使PLC与PLC之间、PLC与上位计算机以及其他智能设备之间能够交换信息，形成一个统一的整体，实现分散集中控制。现在几乎所有的PLC新产品都有通信联网功能，它和计算机一样具有RS-232接口，通过双绞线、同轴电缆或光缆，可以在几公里甚至几十公里的范围内交换信息。
PLC之间的通讯网络是各厂家专用的，PLC与计算机之间的通讯，一些生产厂家采用工业标准总线，并向标准通讯协议靠拢，这将使不同机型的PLC之间、PLC与计算机之间可以方便地进行通讯与联网。
了解了PLC的基本结构，我们在购买程控器时就有了一个基本配置的概念，做到既经济又合理，尽可能发挥PLC所提供的佳功能。
基本指令系统特点
PLC的编程语言与一般计算机语言相比，具有明显的特点，它既不同于语言，也不同与一般的汇编语言，它既要满足易于编写，又要满足易于调试的要求。目前，还没有一种对各厂家产品都能兼容的编程语言。如三菱公司的产品有它自己的编程语言，OMRON公司的产品也有它自己的语言。但不管什么型号的PLC，其编程语言都具有以下特点:
Yaskawa CIMR-V7AU20P71 AC Drive
YASKAWA VARISPEED DRIVE 606PC3 CIMR-PCA20P1 3PH 0.1kW
Juspeed-F Yaskawa Transistor Inverter CIMR-F08AS3 .75kw
YASKAWA VS MINI 200V 3PHASE 0.2KW CIMR-XCBA20P2
YASKAWA VARISPEED CIMR-PBA20P2T 3 PHASE 0.2 KW AC DRIVE
YASKAWA VS mini CIMR-XCBA20P7 200V 3PH 0.7kW
Yaskawa Varispeed CIMR-H11B.D07 23/27 Amp
YASKAWA VS mini V7 CIMR-V7AA20P7 200V 3PH 0.75kW
Juspeed-F Yaskawa Transistor Inverter CIMR-F15AS3 1.5kw
Yaskawa AC Drive CIMR-V7AM43P7 #11224
Yaskawa CIMR-P7U40151 AC Drive 25HP 460V
YASKAWA CIMR-J7AM40P7 J7 DRIVE CIMRJ7AM40P7 NIB
YASKAWA 75 HP/100 HP VFD CIMR-F7U4055 CIMR-U40551E NSFP
YASKAWA ELECTRIC CIMR-XCBA20P2 USPP CIMRXCBA20P2
YASKAWA ELECTRIC CIMR-V7CU45P5 USPP CIMRV7CU45P5
YASKAWA CIMR-J7AM40P2 J7 DRIVE CIMRJ7AM40P2 NIB
YASKAWA ELECTRIC CIMR-V7AM47P5 USPP CIMRV7AM47P5
YASKAWA ELECTRIC CIMR-V7AM40P7 USPP CIMRV7AM40P7
EMS / Yaskawa G5 CIMR G5U43P7, 5HP, 460V, GPD515-B008
YASKAWA ELECTRIC CIMR-V7NU43P7 USPP CIMRV7NU43P7
YASKAWA ELECTRIC CIMR-G3A27P5 USPP CIMRG3A27P5
YASKAWA ELECTRIC CIMR-7.5G2E10 USPP CIMR75G2E10
YASKAWA ELECTRIC CIMR-PCE43P7 USPP CIMRPCE43P7
YASKAWA ELECTRIC CIMR-VU4A0001FA?A NSFP CIMRVU4A0001FAA
YASKAWA Analog Transistor Inverter CIMR-J04AS3-1 3/4HP
Yaskawa 626VM3 Varispeed Spindle Drive CIMR-VMW27P50
YASKAWA ELECTRIC CIMR-V7CU41P5 NSFP CIMRV7CU41P5
YASKAWA ELECTRIC CIMR-2.2G2B-20 USPP CIMR22G2B20
YASKAWA CIMR-V7AM40P71 DRIVE 1HP 400V 3P NEW NIB
YASKAWA ELECTRIC CIMR-J04AS3-1 USPP CIMRJ04AS31
YASKAWA CIMR-G5U2011 REFURBISHED
Yaskawa CIMR-PCA20P7 Varispeed 606PC3 Drive *Tested*
YASKAWA ELECTRIC CIMR-F7U4011 USPP CIMRF7U4011
YASKAWA ELECTRIC CIMR-PCE41P5 USPP CIMRPCE41P5
YASKAWA CIMR-MC5U2011 REFURBISHED
Yaskawa Varispeed G7 CIMR-G7A43PT 3.7KW
YASKAWA ELECTRIC CIMR-E7U2011 USPP CIMRE7U2011
YASKAWA ELECTRIC CIMR-V7NU40P7 USPP CIMRV7NU40P7
Yaskawa 626VM3 Varispeed Spindle Drive CIMR-VMW27P5
Yaskawa 626VM3 Varispeed Spindle Drive CIMR-VMS2018
Yaskawa CIMR-P5U45P5 AC Drive 10HP 460V
YASKAWA V7-4X (CIMR-V7CU40P7) VARI SPEED NEW!!!!!!!!!!!
YASKAWA CIMR-PCU40P7 MINI DRIVE 1HP 3PH 0-460V 0-400HZ.
YASKAWA ELECTRIC CIMR-G3A20P4 USPP CIMRG3A20P4
Yaskawa G5 GPD515 CIMR G5M40P7, 1HP, 460V Drive, 40P7
YASKAWA ELECTRIC CIMR-G5U40P7 NSPP CIMRG5U40P7
Magnetek Yaskawa CIMR-G3U41P5 2HP 460V AC Drive
YASKAWA GPD515C-A017 CIMR-G5U23P7 GOOD.
YASKAWA ELECTRIC CIMR-PCE40P7 USPP CIMRPCE40P7
YASKAWA ELECTRIC CIMR-H2.2B-01 USPP CIMRH22B01
YASKAWA ELECTRIC CIMR-G3A25P5 USPP CIMRG3A25P5
YASKAWA ELECTRIC CIMR-PCU20P2 NSFP CIMRPCU20P2
YASKAWA ELECTRIC CIMR-G3V20-P4 USPP CIMRG3V20P4
YASKAWA CIMR P5M44P0 MOTOR CONTROL
YASKAWA ELECTRIC CIMR-P5M40111F USPP CIMRP5M40111F
YASKAWA VARISPEED DRIVE 626MTII CIMR-MTII-11K *w/ video
YASKAWA ELECTRIC CIMR-04AS2 USPP CIMR04AS2
YASKAWA ELECTRIC CIMR-G3U40P7 USPP CIMRG3U40P7
YASKAWA ELECTRIC CIMR-V7AU45P5 USPP CIMRV7AU45P5
YASKAWA ELECTRIC CIMR-G3A2015 USPP CIMRG3A2015
YASKAWA ELECTRIC CIMR-SBA20P4 NSFP CIMRSBA20P4
YASKAWA ELECTRIC CIMR-P5M47P5 USPP CIMRP5M47P5
YASKAWA ELECTRIC CIMR-G3U53P7 NSFP CIMRG3U53P7
YASKAWA ELECTRIC CIMR-H2.2G2 USPP CIMRH22G2
Yaskawa CIMR-VU4A0018FA?A AC Drive 10HP 460V
YASKAWA ELECTRIC CIMR-J7AU43P7 USPP CIMRJ7AU43P7
YASKAWA ELECTRIC CIMR-E7U4011 USPP CIMRE7U4011
YASKAWA ELECTRIC CIMR-PCD20P2 NSFP CIMRPCD20P2
YASKAWA ELECTRIC CIMR-V7AM20P40-?030 USPP CIMRV7AM20P400
YASKAWA ELECTRIC CIMR-VA4A0011BA?A NSFP CIMRVA4A0011BAA
YASKAWA ELECTRIC CIMR-V7AU47P5 USPP CIMRV7AU47P5
YASKAWA ELECTRIC CIMR-H0.4B USPP CIMRH04B
YASKAWA ELECTRIC CIMR-G3U43P7 USPP CIMRG3U43P7
YASKAWA ELECTRIC CIMR-0.75B NSFP CIMR075B
YASKAWA ELECTRIC CIMR-04AS2 NSPP CIMR04AS2
YASKAWA ELECTRIC CIMR-XCBU20P2 NSFP CIMRXCBU20P2
YASKAWA ELECTRIC CIMR-H3A2045 USPP CIMRH3A2045
YASKAWA ELECTRIC CIMR-F15AS2 NSPP CIMRF15AS2
YASKAWA ELECTRIC CIMR-V7AM20P41-?030 USPP CIMRV7AM20P410
YASKAWA ELECTRIC CIMR-PCU20P2 USPP CIMRPCU20P2
YASKAWA ELECTRIC CIMR-J7AU40P4 NSFP CIMRJ7AU40P4
YASKAWA ELECTRIC CIMR-37 USPP CIMR37
YASKAWA ELECTRIC CIMR-XCBU20P2 USPP CIMRXCBU20P2
YASKAWA ELECTRIC CIMR-G5U43P7 USPP CIMRG5U43P7
YASKAWA ELECTRIC CIMR-V7AM40P2 USPP CIMRV7AM40P2
YASKAWA ELECTRIC CIMR-08AS3-0020 USPP CIMR08AS30020
YASKAWA ELECTRIC CIMR-G3V2015 USPP CIMRG3V2015
YASKAWA ELECTRIC CIMR-G3A20P7 USPP CIMRG3A20P7
YASKAWA ELECTRIC CIMR-V7NU41P5 USPP CIMRV7NU41P5
Yaskawa CIMR-MR5A2011 VS-656 MRS Converter Servo Drive
Yaskawa CIMR-MR5A2011 VS-656 MRS Converter Servo Drive
YASKAWA ELECTRIC CIMR-E7U4011 USPP CIMRE7U4011
YASKAWA ELECTRIC CIMR-37 USPP CIMR37
YASKAWA ELECTRIC CIMR-71616-COVE?R USPP CIMR71616COVER
Yaskawa CIMR-37B.T 230V Series AC Drive CIMR37B.T
Yaskawa Electric CIMR-V7CU45P5 - 460v / 14.8A Drive
YASKAWA ELECTRIC CIMR-SSA-4055 USPP CIMRSSA4055
Yaskawa Juspeed F VFD CIMR-G08A-S2002?0
YASKAWA CIMR P5M43P7 MOTOR CONTROL
Yaskawa Juspeed-F CIMr-15CP3-0023?D Control Unit NEW
Yaskawa CIMR-55WSB 80kVA Varispeed 676 CIMR55WSB 200V B
YASKAWA ELECTRIC CIMR-08AS3-0020 USPP CIMR08AS30020
Yaskawa CIMR-V7AM40P4 GPD 315/V7 AC Drive .4kW *New*
Yaskawa V7, V74X CIMR V7CU20P4, 0.5HP, 230V
YASKAWA ELECTRIC CIMR-H0.4B USPP CIMRH04B
YASKAWA CIMR- PBA20P7 VARISPEED 606 PC3
YASKAWA ELECTRIC CIMR-H2.2B-01 USPP CIMRH22B01
YASKAWA ELECTRIC CIMR-H7.5B.D06 USPP CIMRH75BD06
Yaskawa CIMR-2.2B.T 230V Series AC Drive CIMR2.2B.T
YASKAWA ELECTRIC CIMR-G3A2015 USPP CIMRG3A2015
YASKAWA VFD XCCA20P4 CIMR-XCCA20P4 NEW IN ORIGINAL BOX
Yaskawa Juspeed F VFD CIMR-G08A-S2002?0
YASKAWA GPD515C-A017 CIMR-G5U23P7 GOOD.
YASKAWA CIMR P5M44P0 MOTOR CONTROL
YASKAWA CONTRAVES AC616H/CIMR-H55?H.T 110A AC DRIVE*NNB*
Yaskawa CIMR-3.7B.T 230V series AC Drive CIMR3.7B.T
YASKAWA ELECTRIC CIMR-H110B.D-10 USPP CIMRH110BD10
YASKAWA CIMR-XCBMA0P70 DRIVE 5 AMPS 115V 1 PHASE
Yaskawa E7 drive, CIMR-E7U42P2, spec 42P21B
Yaskawa CIMR-F08AS4-102?0 Juspeed-F AC Drive *NEW*
Yaskawa / Saftronics PC7 CIMR V7AU40P4, 40P4, 460V
Yaskawa CIMR-0.75B.T 230V Series AC Drive CIMR-0.75 B.T
Yaskawa PC5 CIMR P5A43P7, 5HP, 460V, FP543P7, 43P7
Saftronics GP543P7 MagneTek GPD505V-B008
YASKAWA ELECTRIC CIMR-MTIII-15K USPP CIMRMTIII15K
Yaskawa CIMR-R5U40181 RC5 Regenerative Converter
YASKAWA Analog Transistor Inverter CIMR-J04AS3-1 3/4HP
YASKAWA ELECTRIC CIMR-F55AS3 USPP CIMRF55AS3
YASKAWA VARISPEED-626M5 CIMR-M5A20110
Yaskawa GPD 315 AC Drive CIMR-V7AM40P2 0.2kW Magnetek
YASKAWA ELECTRIC CIMR-G3V2015 USPP CIMRG3V2015
Yaskawa CIMR-5.5B.E05 230V Series AC Drive CIMR5.5B.E0
YASKAWA ELECTRIC CIMR-0.75B NSFP CIMR075B
Yaskawa 626VM3 Varispeed Spindle Drive CIMR-VMW27P5
YASKAWA ELECTRIC CIMR-2.2B NSFP CIMR22B
Juspeed-F Yaskawa Transistor Inverter CIMR-F08AS3 .75kw
Magnetek Yaskawa CIMR-G3U41P5 2HP 460V AC Drive
NEW YASKAWA 15 HP AC VFD DRIVE CIMR-E7U49P0 E7BVB021A
Yaskawa CIMR-3.7B.E04 230V Series AC Drive CIMR3.7B.E0
YASKAWA ELECTRIC CIMR-G3U4030 USPP CIMRG3U4030
Yaskawa Varispeed G7 CIMR-G7A43PT 3.7KW
YASKAWA ELECTRIC CIMR-P5M25P51F USPP CIMRP5M25P51F
YASKAWA ELECTRIC CIMR-V7AM45P51 USPP CIMRV7AM45P51
Yaskawa CIMR-H3.7B.D04 Transistor Inverter
YASKAWA ELECTRIC CIMR-V7NU45P51 NSFP CIMRV7NU45P51
NEW YASKAWA 230 V 3 PHASE VS MINI DRIVE CIMR-XCBA21P542
YASKAWA ELECTRIC CIMR-PCU40P7 USPP CIMRPCU40P7
Yaskawa CIMR-F7U43P7 AC Drive 5HP 460V
YASKAWA ELECTRIC CIMR-PCU40P4 NSFP CIMRPCU40P4
YASKAWA ELECTRIC CIMR-PCU40P4 USPP CIMRPCU40P4
Yaskawa CIMR-F7U Version 3020 Drive User Manual
YASKAWA ELECTRIC CIMR-P5M40P71F USPP CIMRP5M40P71F
Yaskawa Varispeed Spindle Drive CIMR-F7U4030 F7U40301E
YASKAWA ELECTRIC CIMR-PCU41P5 USPP CIMRPCU41P5
Yaskawa Varispeed Inverter 616G5 CIMR-4045 380V 45KW
YASKAWA YASNAC CIMR MT III 7.5K SPINDLE DRIVE
YASKAWA YASNAC CIMR MT II 7.5K SPINDLE DRIVE
YASKAWA /EMS CIMR-G5U43P7 VARIABLE FREQ AC DRIVE
Yaskawa E7 drive, CIMR-E7U42P2, spec 42P21B
YASKAWA CIMR-J7AAB0P7 VS MINI J7 AC DRIVE
Yaskawa VariSpeed 616G5 AC CIMR-G5A22P2
Yaskawa CIMR-XCBA41P5 VS Mini 380-460v 3ph 3.7kva NEW
YASKAWA VFD XCCA20P4 CIMR-XCCA20P4 NEW IN ORIGINAL BOX
Yaskawa V7, V74X CIMR V7CU20P4, 0.5HP, 230V
YASKAWA CIMR-XCAA20P4 VS mini DRIVE SPINDLE
CIMR-P7U43000- 480V 675A 500HP NEMA 1 AC DRIVE YASKAWA
Yaskawa (Saftronic) VS 606V7 P/N CIMR V7AT42P2 Sp: 42P2
YASKAWA Varispeed F7, CIMR-F7U42P2
EMS/ Yaskawa/ Saftronics PC3 41P5, CIMR PCU41P5, 460V
Saftronics PCU41P5 MagneTek GPD333-DS043 Omron 3G3XV
YASKAWA SPINDLE DRIVE CIMR-MTIII-11K
Yaskawa / Saftronics E7 CIMR E7U42P2, 42P2, 3HP, 460V
FAST YASKAWA CIMR-MTIII-11K SPINDLE DRIVE REBUILD
FAST YASKAWA CIMR-MTIII-7.5K SPINDLE DRIVE REBUILD
Yaskawa V7, V74X CIMR V7CU43P7, 5HP, 460V, 43P7
V7-4X Varispeed, CIMRV7CU43P74
CIMR-P7U41600-4?80V 304A 250HP NEMA 1 AC DRIVE YASKAWA
Yaskawa CIMR-P5U43P7 AC Drive 5HP 460V
Saftronics 15HP G3 CIMR G3U4011, Yaskawa G3U40111
YASKAWA/EMS CIMR-G5U43P7 VARIABLE FREQ AC DRIVE NIB!!!
Yaskawa F7 5HP Drive , CIMR-F7U43P71, 460 v , 43P71
YASKAWA CIMR-J7AA20P1 VS mini J7 AC DRIVE 0.1kW
YASKAWA CIMR-H7.5B.D06 460V 10HP AC DRIVE CIMR * TESTED
Yaskawa GPD 315 AC Drive CIMR-V7AM40P2 0.2kW Magnetek
Yaskawa / Saftronics G5 CIMR G5U40P7, 1HP, GPD515
Yaskawa AC Drive 2HP 480V Adjustable # CIMR-F15AS2
YASKAWA VARISPEED 676 TRANSISTOR INVERTER CIMR-11WS
YASKAWA CIMR- PBA20P7 VARISPEED 606 PC3
Yaskawa / Saftronics VG5 CIMR G5U42P2, 42P2, 3HP, 460V
YASKAWA CIMR-P5U2011 VG5 AC DRIVE /1 YEAR WARRANTY
YASKAWA CIMR-XCAA21P5 VS mini DRIVE
CIMR-P7U40900- 480V 180A 150HP NEMA 1 AC DRIVE YASKAWA
CIMR-P7U41100-4?80V 240A 200HP NEMA 1 AC DRIVE YASKAWA
Yaskawa 676GL5-JJ Varispeed CIMR-L5JJ4015 15KW FreeShip
Yaskawa AC Drive 2HP 480V Adjustable # CIMR-F15AS2
Yaskawa Varispeed Inverter 616G5 CIMR-4045 380V 45KW
YASKAWA VARISPEED 656RC5 CIMR-R5U4045 25 HP *NEW*
YASKAWA CIMR-H7.5B.D06 460V 10HP AC DRIVE CIMR * TESTED
YASKAWA CIMR-H7.5B.D06 460V 10HP AC DRIVE * TESTED
Saftronics 15HP G3 CIMR G3U4011, Yaskawa G3U40111
YASKAWA VARISPEED 676 TRANSISTOR INVERTER CIMR-11WS
Yaskawa VS Mini CIMR-XCAA20P1 200V 3phase
YASKAWA CIMR-XCAA20P1 VS mini DRIVE
YASKAWA CIMR-XCAA20P2 VS mini DRIVE
Yaskawa CIMR-G5A40P7 3PH 0-460VAC for Parts
Yaskawa AC motor drive CIMR-V7AA20P1 CIMRV7AA20P1
Yaskawa CIMR-J7AM40P40 3/4HP 460VAC Drive GPD 305 NIB
Yaskawa GPD 305 AC motor drive CIMR-J7AM40P2 Magnetek
YASKAWA CIMR-F08AS3-102?0 JUSPEED-F AC DRIVE (NEW)*
Yaskawa AC motor drive CIMR-PCD20P1 NIB CIMRPCD20P1
Yaskawa AC motor drive CIMR-V7AA20P4 CIMRV7AA20P4
Yaskawa AC motor drive CIMR-J7AMB0P4 NIB CIMRJ7AMB0P4
Yaskawa AC motor drive CIMR-PCU40P4 NIB CIMRPCU40P4
Yaskawa CIMR-V7AM20P1 Variable Speed AC Drive NIB
YASKAWA Varispeed L7 CIMR-L7B4011 400V,11KW
Yaskawa Spindle Drive VS-626 CIMR-MTIII CIMR-MTII CDMR