Structure And Mode Of Operation; Transducers; Sg Covering Agent - Hbm U9C Montageanleitung

Structure and mode of operation

4 Structure and mode of operation
4.1

Transducers

The measuring body is a steel loaded member on which strain gauges (SG)
are installed. The influence of a force deforms the measuring body, so there is
deformation in places where the strain gauges are installed. The SG are
attached so that two are stretched and two are compressed when a force is
applied. The strain gauges are wired to form a Wheatstone bridge circuit. They
change their ohmic resistance in proportion to their change in length and so
unbalance the Wheatstone bridge. If there is an excitation voltage, the circuit
produces an output signal proportional to the change in resistance and thus
also proportional to the applied force. The strain gauge arrangement is chosen
to compensate, as much as possible, for parasitic forces and moments (e.g.
lateral forces and eccentricity influences), as well as the effects of temperature.
4.2

SG covering agent

To protect the SG, the force transducers have thin cover plates that are welded
on the bottom and, in versions with a nominal (rated) force of up to 200N, on
the top side. This method offers very good protection against environmental
conditions so that the U9C reaches the protection class IP67. In order to retain
the protective effect, these plates must not be removed or damaged in any
way.
10
A3815-1.4 HBM: public
U9C