Below please find answers to your questions:
«1. Is that the right procedure for relative deformation calculation?»
We have forwarded you a link to an article specifying the process of the coefficient calculation — it depends on sensitivity level of the strain-gauges as well as on their particular mounting technique.
«2. Should the voltmeter readings be the same at the beginning of measurements process?»
Yes — it is necessary to set them to zero prior to starting the measurement process, since the initial displayed value is not related to the load impact — it is actually caused by strain gauge deposition, input amplifier and cable displacement.
LLC «ETMS» Support team