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SIMULTANEOUS MEASUREMENT OF TEMPERATURE AND STRAIN USING FOUR CONNECTING WIRES , Technical Memorandum


Authors: Allen R. Parker, Jr.


Report Number: NASA-TM-104271


Performing Organization: NASA Dryden Flight Research Center, Edwards, CA


Abstract: This paper describes a new signal-conditioning technique for measuring strain and temperature which uses fewer connecting wires than conventional techniques. Simultaneous measurement of temperature and strain has been achieved by using thermocouple wire to connect strain gages to signal conditioning. This signal conditioning uses a new method for demultiplexing sampled analog signals and the Anderson current loop circuit. Theory is presented along with data to confirm that strain gage resistance change is sensed without appreciable error because of thermoelectric effects. Furthermore, temperature is sensed without appreciable error because of voltage drops caused by strain gage excitation current flowing through the gage resistance.


Distribution/Availability: Unclassified - Unlimited


Subject Category: 35


Availability:
  •     Format(s) on-line:
          Postscript (168 KBytes)
          PDF (91 KBytes)


    Report Date: November 1993


    No. Pages: 12


    Funding Organization: WU 505-70-63


    Keywords:      Bridge circuits; Instrumentation; Signal demultiplexer; Simultaneous measurement; Strain gage measurements; Thermocouple; Transducers


    Notes: Presented at SEM Fall Conference and Exhibit — on Structural Testing Technology at High Temperature-II, Ojai, California, November 8, 1993.