A measurement system to automate laboratory testing in soils

This paper presents a personal computer (PC) based system to automate laboratory testing of soils. The output voltages from eight transducers that measure displacements in specimen under oedometer tests are conditioned and measured by the system. Another transducer is used to measure the load applied to a specimen on a direct shear-box apparatus using a load ring. Severe restrictions are imposed to the system, not only on the accuracy (in oedemeter test full scale displacement is 10 mm and the required resolution is 0.002 mm) but also on stability with the time and temperature, since the measurement procedure can take up to one week.