使用labview fpga模块开发可编程自动化控制器外文文献及翻译大学论文Word下载.docx

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2、ementsrequiredgenerateasinglewritesequencethatareuponexecution“write_to_transmitter”task,getlatchedinternallateranalysis.task“read_out_receiver” parallel“compare_data”compareprevious thecorrespondingmostrecentreceiverIfanydiscrepancyoccurs,flagsanerrorbywritingvalueswellsimulationimmediatelystoppedi

3、foccurs.Besidesabovementionedtasks,mclkx16,masterresetsignals“txrx”loopfeature.consideredtrivial,willnotillustratedhere,butreferredwithinitself.corebehaviorallevel“forloop”executespossiblecombinationsverifysamegetsproperlyreceiver.showed below in figure 21.Nextportdefinitionscomesdirections.Directio

4、nsspecifiedinput,orinout（bidirectional）,table1.Next specificationdirectionsdeclarationsignals.Internaldeclared“wire”“reg”types.Signalstypecontinuosassignments,alsocalledcombinatorialstatements.assignments“always”block,oftenusesequentiallogicnecessarily.ForfurtherexplanationseeaVerilogreferencebook.t

5、ypes3.Wehavenowpasseddeclarations,readylookatactualimplementation.Usinghardwaredescriptionlanguageus describefunctionmoremanner,ratherthanfocusonitsimplementationgatesoftwareprogramminglanguage, functionsproceduresbreakslargerprogramsintoreadable,manageablecertainlymaintainablepieces.providesfunctio

6、nsconstructs,analogousprocedures.A taskequivalentmultiplelinescode,wherecertaininputsaffectsoutputsvariables.usuallytakesplacecoderepeatedlydesign,hencemakesdesigneasiermaintain. caninputs,alwaysonlyoneoutput,whilebothevensomecases,noneach.Belowshownholdstatements,describe“shift”modeWith the LabVIEW

7、 FPGA Module and NI RIO hardware, you now can use LabVIEW, a high-level graphical development environment designed specifically for measurement and control applications, to create PACs that have the customization, flexibility, and high-performance of FPGAs. Because the LabVIEW FPGA Module configures

8、 custom circuitry in hardware, your system can process and generate synchronized analog and digital signals rapidly and deterministically. Figure 1 illustrates many of the NI RIO devices that you can configure using the LabVIEW FPGA Module.Figure 1. LabVIEW FPGA VI Block Diagram and RIO Hardware Pla

9、tforms NI RIO Hardware for PACs Historically, programming FPGAs has been limited to engineers who have in-depth knowledge of VHDL or other low-level design tools, which require overcoming a very steep learning curve. With the LabVIEW FPGA Module, NI has opened FPGA technology to a broader set of eng

10、ineers who can now define FPGA logic using LabVIEW graphical development. Measurement and control engineers can focus primarily on their test and control application, where their expertise lies, rather than the low-level semantics of transferring logic into the cells of the chip. The LabVIEW FPGA Mo

11、dule model works because of the tight integration between the LabVIEW FPGA Module and the commercial off-the-shelf （COTS） hardware architecture of the FPGA and surrounding I/O components.National Instruments PACs provide modular, off-the-shelf platforms for your industrial control applications. With

12、 the implementation of RIO technology on PCI, PXI, and Compact Vision System platforms and the introduction of RIO-based CompactRIO, engineers now have the benefits of a COTS platform with the high-performance, flexibility, and customization benefits of FPGAs at their disposal to build PACs. Nationa

13、l Instruments PCI and PXI R Series plug-in devices provide analog and digital data acquisition and control for high-performance, user-configurable timing and synchronization, as well as onboard decision making on a single device. Using these off-the-shelf devices, you can extend your NI PXI or PCI industrial control system to include high-speed discrete and analog control, custom sensor interfaces, and precise timing and control. NI CompactRIO, a platform centered on RIO technology, provides a small, industrially rugged, modular PAC platfo