1794-OB8EPXT***
价格:999.00
1794-OB8EPXT***1794-OB8EPXT***1794-OB8EPXT***PLC以微处理器为核心,具有微机的许多特点,但它的工作方式却与微机有很大不同。微机一般采用等待命令的工作方式工作。PLC是按集中输入、集中输出,周期性循环扫描的方式进行工作的。每一次循环扫描所用的时间称为一个扫描周期。对每个程序,CPU从条指令开始执行,按顺序逐条地执行指令做周期性的程序循环扫描,如果无跳转指令,则从条指令开始逐条顺序执行用户程序,直至结束又返回条指令,如此周而复始不断循环。PLC在每次扫描工作过程中除了执行用户程序外,还要完成内部处理、输入采样、通信服务、程序执行、自诊断、输出刷新等工作。PLC工作的全过程包括三个部分,即上电处理、扫描过程和出错处理。PLC工作的全过程可用图4所示的运行框图来表示。PLC通电后,CPU在系统程序的控制下***行内部处理,包括硬件初始化、I/O模块配置检查、停电保持范围设定及其他初始化处理等工作。PLC有很强的自诊断功能,PLC每扫描一次执行一次自诊断检查,确定PLC自身的动作是否正常,如电源检测、内部硬件是否正常、程序语法是否有错等。如检查出异常时,CPU面板的LED及异常继电器会接通,在特殊寄存器中会存入出错代码;CPU能根据错误类型和程度发出信号,甚至进行相应的出错处理,使PLC停止扫描或强制变成STOP状态。PLC运行正常时,扫描周期的长短与用户应用程序的长短、CPU的运算速度、I/O点的情况等有关。通常用PLC执行1KB指令所需时间来说明其扫描速度(一般1-10ms/KB)。值得注意的是,不同指令执行时间是不同的,故选用不同指令所用的扫描时间将会不同。若用于高速系统要缩短扫描周期时,可从软硬件上同时考虑。PLC周期性循环扫描工作方式的显著特点是:可靠性高、抗干扰能力强,但响应滞后、速度慢。TEXASINSTRUMENTSPLC2587695-8014NSFP25876958014TexasInstrument500-5016AnalogOutputModuleALLENBRADLEY1326AB-B420ES2LUSPP1326ABB420ES2LRANSBURG75780-00NSPP7578000ASEABROWNBOVERIEH300C-YL11EXNSFPEH300CYL11EXTexasInstruments500-5023ALLENBRADLEY1336-B003-EAD-FA2-L2USPP1336B003EADFA2L2KEYENCECORPVG-036NSFPVG036ASEABROWNBOVERI3HAB-2206-1/1USPP3HAB220611DETRONICSR9105-P5002USPPR9105P5002PanasonicACServoDriverMUDS083A1MFreeShipLUCENTTECHNOLOGIESD-CI-B2USPPDCIB2TexasInstrumentsRTU-AOT-1AnalogOutputBoard520-066TexasInstrumentsSeries305-04B/05B10-SlotRack!TEXASINSTRUMENTSPLC140-1111NSPP1401111PanasonicServoMSDA041D1A&MotorM***A041C1C400WLNCFANUCA860-0346-T041USPPA8600346T041ASEABROWNBOVERI3HAB2136-001USPP3HAB2136001TEXASINSTRUMENTSPLC505-6511NSPP5056511PanasonicACServoMotorM***A082C2F750WFreeShipAseaBrownBoveriABBAxodynServoDriveD05010/R0004TEXASINSTRUMENTSPLC505-4332NSPP5054332ASEABROWNBOVERIEH450C-32VDC-TNSPPEH450C32VDCTGEFANUCIC600RB751USPPIC600RB751ASEABROWNBOVERIEH450C-32VDC-TNSPPEH450C32VDCTSIEMENS6SL3353-6TE411CA3NSFP6SL33536TE411CA3PanasonicACServoDriverDriverMSD043A1XXVFreeShipOMRONIDSC-C1DR-A-EUSPPIDSCC1DRAETEXASINSTRUMENTSPLC500-5019USPP5005019ASEABROWNBOVERI57775840NSFP57775840PERCEPTRON916-4079DIGITALCONTOURLASERSENSORREVCC0400-X0000-Y0126-Z0287PANASONICACSERVODRIVEMFDDTB3A2L015.0KWSIEMENSTIPLCXM22401LMOTORINTERFACEMODULEL00OASEABROWNBOVERI3E-032176USPP3E032176TEXASINSTRUMENTSPLC500-5027NSPP5005027TexasInstrumentsLoopAccessControlModulePPM550-416505-CP1434TFTexasInstrumentsSiemensTI505CP1434TF(AB01)ACSERVODRIVERPANASONICMATSUSHITAELECTRICMSD021PIEA01WORKINGSIEMENS6AG4040-0AG30-0PA0NSFP6AG40400AG300PA0PanasonicMSDA023A1AACServoDriverNewinBoxFreeShipASEABROWNBOVERI48990001-FEUSPP48990001FEPanasonicMDD153A1VEACServoDriverASEABROWNBOVERI57340001-K/1USPP57340001K1PanasonicMSD5A1P1EACServoDriverFreeShipSTR-410TTexasinstrumentsTILoaderSTR410TD-282ALLENBRADLEY1361-R065-2-7USPP1361R06527TEXASINSTRUMENTSPLC944910-8001USPP9449108001TISiemensCTi500-2151-A5002151PowerSupply2151APLCASEABROWNBOVERI05MA21USPP05MA21ASEABROWNBOVERIACH501-005-4-00P2USPPACH501005400P2TEXASINSTRUMENTS5TI-1032-2SEQUENCERMODULE5TI10322TEXASINSTRUMENTSPLC2490019-0001USPP24900190001TEXASINSTRUMENTS500-5019WORDOUTPUTMODULENEW5005019MODICON140-ACI-030-00FNFP140ACI03000YASKAWAELECTRICJAMSC-B1083CNSFPJAMSCB1083CASEABROWNBOVERIDSTC-456NSFPDST56TEXASINSTRUMENTSPLC505-7202USPP5057202ASEABROWNBOVERI57088648NSFP57088648TexasInstrumentsPM550-400TEXASINSTRUMENTSPLC500-9940USPP5009940ASEABROWNBOVERI57310001-GPUSPP57310001GPALLENBRADLEY813S-VOAUSPP813SVOAASEABROWNBOVERIR58113972USPPR58113972)