1. www.natinst.com Measurement Fundamentals Rajesh Vaidya DAQ Software Engineer Wed 10:15a, 12:45p, and 3:30p Colorado (6A) Rajesh Vaidya DAQ Software Engineer Wed 10:15a, 12:45p, and 3:30p Colorado (6A)

2. www.natinst.com Presentation Outline  Design considerations  Hardware and software selection  Demo of sample measurement systems  Factors affecting accuracy  Parting thoughts  Design considerations  Hardware and software selection  Demo of sample measurement systems  Factors affecting accuracy  Parting thoughts

3. www.natinst.com Design Considerations  Define system requirements Classify application based on signal types (AI/AO/DIO/CTR or combination) Number of I/O channels Speed/accuracy Signal conditioning requirements Portability Scalability Backward compatibility with existing systems  Define system requirements Classify application based on signal types (AI/AO/DIO/CTR or combination) Number of I/O channels Speed/accuracy Signal conditioning requirements Portability Scalability Backward compatibility with existing systems

4. www.natinst.com Measurement System Components Physical phenomena (Temperature, pressure, etc.) Transducer Voltage current, resistance Signal conditioning PC with data acquisition Device + Measurement software wiring

5. www.natinst.com Signal Types and Conditioning Requirements

6. www.natinst.com Defining Requirements (cont’d.)  Number of I/O channels Low – DAQ board Medium –Higher channel DAQ board –Multiple DAQ boards High –SCXI-based system  Number of I/O channels Low – DAQ board Medium –Higher channel DAQ board –Multiple DAQ boards High –SCXI-based system

7. www.natinst.com Requirements (cont’d.) PC-4350 PCI-603x PC-611x PCI-5112 Speed vs. Accuracy

8. www.natinst.com Additional Considerations  Multifunction DAQ board vs. computer-based instrument  Does your system need portability? PCMCIA, PCI, AT, PXI, USB, FireWire, serial, parallel  Multifunction DAQ board vs. computer-based instrument  Does your system need portability? PCMCIA, PCI, AT, PXI, USB, FireWire, serial, parallel

9. www.natinst.com Software/Programming Interface  Interactive interface (ready to run) VirtualBench  Programmatic interface  LabVIEW LabWindows/CVI C++/Visual Basic/Delphi ActiveX controls  Interactive interface (ready to run) VirtualBench  Programmatic interface  LabVIEW LabWindows/CVI C++/Visual Basic/Delphi ActiveX controls

10. www.natinst.com DAQ Designer 99  Online system configuration tool www.natinst.com/daq/ddonline.htm  Online system configuration tool www.natinst.com/daq/ddonline.htm

11. www.natinst.com Demo VirtualBench and LabVIEW Interface

12. www.natinst.com Making Accurate Measurements  Signal resolution  Grounding issues  Line noise  Environmental factors  Calibration  Source impedance  Signal resolution  Grounding issues  Line noise  Environmental factors  Calibration  Source impedance

13. www.natinst.com Accuracy Issues (cont’d.)  Signal resolution Type of A/D Converter – 12-bit vs. 16-bit Gain setting  Grounding issues Differential Reference single ended Non-Referenced single ended  Signal resolution Type of A/D Converter – 12-bit vs. 16-bit Gain setting  Grounding issues Differential Reference single ended Non-Referenced single ended

14. www.natinst.com Accuracy Issues (cont’d.)  Line noise Use filtering to eliminate 50-60 Hz line noise  Environmental factors Use shielded cables Distance system from noise sources  Calibration Perform regular calibration  Source impedance High impedance sources can cause problems  Line noise Use filtering to eliminate 50-60 Hz line noise  Environmental factors Use shielded cables Distance system from noise sources  Calibration Perform regular calibration  Source impedance High impedance sources can cause problems

15. www.natinst.com Demo – Temperature Measurement

16. www.natinst.com Demo – Frequency Measurement

17. www.natinst.com Deploy the System  Stand-alone systems  “Executable” versions for clients  Part of networked DAQ system DataSocket RDA VI Server  Stand-alone systems  “Executable” versions for clients  Part of networked DAQ system DataSocket RDA VI Server

18. www.natinst.com Measure Anything / Automate Everything  PC-based measurement systems offer: Superior performance Lower cost Better integration Faster development cycles Distributed measurement capabilities  PC-based measurement systems offer: Superior performance Lower cost Better integration Faster development cycles Distributed measurement capabilities