Answer from Claudio
What is it and how should I consider it?
The dynamic penetrometer in its most “pure and theoretical” form is composed of a weight that falls from a known height on a rod that is consequently fixed to it. For less complex instruments like the DM30 the movement of the hammer is entrusted to a support that rests on the top of the rods.
This system receives the blow from the falling mass and transmits it, in a semi-rigid way (the metal has its own mass and elasticity), to the underlying rods. The evaluation of the presence of this system allows to correct the response of the installation based on this support.