ABBAI8933BSC690141R1行程开关、接近开关、传感器及变送器、电磁线圈、接触器、继电器、控制阀等等。这在PLC中通常称为I/O点，它是用端子的形式与工业现场的器件或设备进行连接的，PLC在使用时只需将现场的各种设备与相应的I/O端相连接，即可投入运行。OMRONPLC整体型一体机的数字量IO点一般是以6：4的比例来分配输入和输出信号点的，比如20个IO点的PLC模块可以接12个点的输入信号，还可以接8个点的输出信号。PLC的数字量输入类型一般常见的都是DC型号的，就是直流输入，当然也有交流输入。直流输入一般都是24V，外接的信号一般都为无源的开关量信号。所谓开关量信号或者是数字量信号，就是表现出的信号只有两种状态，象开关一样：或者是开或者是关，没有第三种状态。在计算机中表现的是：0或者是1；电气电路中表现的是：接通或者是切断，等等。在PLC的上部为输入端子连接排，左侧是PLC的输入电源接点。挨着的是输入信号的端子。因为输入的外接信号通常都是无源的信号，所以在接入PLC端子时，要提供电源形成合适的电流回路，在PLC上为方便输入信号的电源供取，提供有24VDC（250MA）直流电源引出端子。如图上所示。所有的I/O接口电路均采用光电隔离，使工业现场的外电路与PLC内部电路之间电气上隔离。各输入端均采用R-C滤波器，其滤波时间常数一般为10~20ms。在COM和信号输入端子间接入电源（该电源由PLC输出的+24VDC引用），形成输入回路。PLC的一个输入点单独对应一个内部电路，如果信号是＝1时，也就是当输入信号（外部开关）闭合，输入点与输入公共端COM接通有适当电流形成输入回路时，该输入标识指示灯会点亮。在PLC里这个点的输入DI＝1。我们看到PLC的输入端电气回路已经不是简单的电气接线形式，通过光电耦合和电容电阻，提高识别输入信号变化的程度，并隔离外部的可能的干扰。同样，交流输入电路也是类似。值得注意的是，输入的电源在通常情况下，COM端可以或正或负，但对于NPN或者是PNP这种晶体管输入的外部信号，就要在接线上给予注意，日式的PLC习惯是NPN型的信号连接。NPN型传感器要求公共端接24VDC+极；PNP型传感器则正好相反，要求公共端接24VDC－极。因为PLC输入端子只有一个公共端－COM，如果信号中又有PNP型信号或者是NPN型信号的话，那么在选型上或者是接线上要做相应的调整。以下是几种输入回路：无源接点的信号回路，串入的电源可由PLC供电端引，公共端可接电源的正极/负极；1756-A41756-CN2R1756-EN2T1756-L621756-PA721786-RG61786-TPS1786-XT1794-ACNR151794-IB321794-IE121794-OE121794-OV321794-PS131794-PS31794-TB321794-TB3GTM-T88IVM129HIC200ALG260DIC200ALG260EIC200MDL650F140-CMN-6300140ACI04000140ACO02000DKC03.3-040-7-FWPMC-2/11/08RD316T33WP02S29Y01SS302H-3Z-D56GT2002-0EB2031C014-503-4-001746-IB161746-IB81746-IM161746-NI41746-NO4I1746-NO8V1746-OB161746-OB81746-OW161746-P41747-BA1747-L5311747-L5521747-L5531756-A71756-BA11756-DNB1756-ENBT1756-IB321756-IF161756-L631756-OB16E/A1756-OB321756-OF81763-L16BWA1769-IQ321747-CP31762IF20F21762-IQ161762-OW81769-0F41769-ECR1769-IF81769-IQ161769-IQ321769-L32C1769OB321769-OB321769-PA41769SDN1784PCIC1786TPS1786XT140DDI353006SN1118-0DK23-0AA2MDS60A0015-54A3-4-00140CRA21110140ACI03000140CPU11302PC-E984-265A06B-6132-H0021746-HSRV1762-L24BWA1757-SRM3HAC16831-11746-P21756-PA75MVME162PA-SE344CP60005X00226G01PMC-2/11/08电源2090-U3CK-D442098-DSD-005X1746-A41746-OW163HAC020208-001/043HAC025062-006/013HAC17484-8/06HDD02.2-W040N-HD32-01-FW395IC300DQM202IC300MIX902MVI46-MCMMVME167-035A22B-A5P0N10422B-D010N1041746-A41746-OB16ATV71HD37N4ZRTAC-011746-IB321746-NI41746-NI81746-NO4V1746-NT81746-P21746-P41747-L5511747-SN1756-L621C31224G011745-E1511745-LP151TACMP-454-0-0-21756-L62BRC100ICSE08B5*24VJRMSP-P8601140ACI03000140ACO02000140CRA93200140CRP93200140DDI35310140DDO35300140NOE771011756-PA72MVI94-MCM803316738425035823842522215PT4626-5M-6/18HG2-6400PSCA-SS-70-109905-462PU515A3BSE032401R11756-A4140CRA93200140DDI84100140DDO84300140XCP51000140XTS002001734-0B8E1734-0E2V1734-IE2VE7280728-06-029E7281FT5076-0AC01-21756-0F81756-A41756-CNB1756-ENBT1756-IF161756-L611746-NR4MVI46-MCM80350APFEAIIIPFTL101A-1.0KNC98130-A1002-C76-03-25140AC013000140ACI04000140ACO02000140AVI03000140CRA93200140CRP93200140DD035300140DDI35300140DDI35310140NOE771011756-A101756-A131756-A171756-A71756-CNBR1756-ENBT1756-HSC1756-IF161756-IH16I1756-IV321756-L621756-N21756-OV32E1756-PA721756-TBCH6DD1600-0AJ06DD1606-3AC06DD1610-0AH06DD1611-0AD06DD1662-0AB06DD1688-0AD06ES7441-2AA03-0AE0UN972-0CA23-0XA0DAI05DS200ITXSG1ABBP22NRXB-LNF-NS-00CS5133BSE000435R1VME7768-320000375NFTP01NKMF01-2NKTU01-15P332G-MLFCM10E1492-CM1771-LA0021492-CM1771-LD0021492-CM1771-LD0051492-CM1771-LD0131492-CONACAB005D1492-CONCAB005S31492-CONCAB005Y1492-CONCAB005Z1786-CTK1786-RG61786-TPS1786-XTA06B-6059-H002FR-A740TM218LDA40DR2HNTM2AMM6HTTM2DOCKN140ARI03010140CPU53414B140DDO353001783-US06T01F1783-US08TMC9090-GF56RF‐IN‐IPS1256RF‐TG‐50HT56RF‐TR‐809057RF‐HH‐56A57RF‐HH‐56US2IC693CBL327IC693CBL328IC693MDL6551756-ENBT1756-L622094-BC02-M022094-BM01-M2094-BM01-S22B-D6PON1043HAC1494-1ABBDSQC509VME48108-00F-GMINITEMPMT41394C-AM50MV156-MCMFCP270140ACI04000140ARI03010140CPS11420140CPU67160140CRA93200140CRP93200140DDI35300140DDO35300140NOE77101140XBP00600140XBP01600140XCP51000140XTS002006ES7291-8GH23-0XA06NH9720-3AA006NH9860-1AA00140ACI03000HVE-501756-IB321756-IR6I1756-OB321784-CF64XR809090-001011785-L40BKSD1-16KSD1-48JAMSC-B1083C1C31122G011C31125G021C31129G031C31132G011C31224G011C31227G011C31234G015X00070G041C31116G045X00119G015X00121G016SN1118-ODK23-0AA26SN1227-2ED10-0HA0SNAT-7780-CNT6GT2002-0EB20E300/04380AIC200CHS022IC200GBI001IC200MDL650IC200MDL750IC200PWR1021C31205G01A5E00104787A5E00104867PSCCM22AANH2310240225DX363HAC023195-001FBM06P0400YGSR750-P5-G5-S5-HI-A20-RVMS-2110-24VDCP0973CAPU20-ONSP28-3SXD64-3FIC693CPU374IC698PSA3501756-CNBR1756-ENBT1756-IF161756-OB16E1756-OF41756-PA72F-62176FC5447-0AA00-0AA1CI8101746-NI81747-L5411756-L63/BVW3A11016SN1118-0NJ01-0AA16SN1118-0NK01-0AA1ZAG2206-11S3HAC025784-001/00DSQC651140CPU11303140CPU43412AE3X-NA11F3A99190G01140ACO13000140CPU65150140CRA931001769-L32EIC693CHS391JZNC-XIU01BJZNC-XRK01D-1JZRCR-XPU03BPCI-5565PIORC-110000SWS15101A20B-0008-0440AIC693ALG221HCS02.1E-W0012-A-03-NNNNHCS02.1E-W0028-A-03-NNNNHCS02.1E-W0054-A-03-NNNNMSK040C-0600-NN-M1-UP1-NNNNFCP270SRX1400IC698CPE010CP5621-6GK15621AA0057C442ATV312H055M2330130-080-03-05330180-91-055X00119G016RA8232-1DB0CJ1W-CPU11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