Strain gages: back to basics

This series of articles deals with resistance strain gages, the transducers based on them, and the signal conditioning required and desired for them. In the first article, it was explained that one should consider all resistors as voltage generators. In addition, one should select a test procedure or signal conditioning, or both, that allows the determination of whether such contaminating voltages are present during a test. Such tests are vital to data integrity. In the second article, causes and effects of resistance changes due to undesired environment stimuli were considered. Some of the methods that can be used to control those effects were suggested. In this third article, procedures for documenting the environments to which the strain gage responds, and whether the responses are desired, are discussed.