chapter  11
Indirect determination of the a-w relation of HSC through three-point bending
Pages 10

All signals together with the time, t, were recorded using an analog to digital converter and an AT Personal Computer. The test was controlled by a feedback signal that included contributions from both the piston displacement and the COD. The feed back signal, 5, was created by analog addition of the corresponding signals:

Fig. 1. Photo of test set-up.