HBM CMD Serie Bedienungsanleitung Seite 78

Tips for piezoelectric measurement technology
76
S Then read the display at 10 kN, for example. A value
of 38010 pC could be displayed here, for example.
The new sensor sensitivity is subsequently calculated
as 38010/10000 = 3.801 (pC/N).
S Enter this sensor sensitivity of 3801 (pC/kN) in the
Sensor sensitivity field in the CMD Assistant, and
set the unit to kN.
S Enter the measuring range 100 in the Physical input
range field in the CMD Assistant, the display shows
the most suitable value to have been set: 99.99747.
This produces an output voltage on the charge amplifier
of +10 V at 100 kN.
Important
When pre‐stressing, the force must be measured with
the sensor itself. Use the sensitivity stated in the specifi­
cations to do this. Since the pre‐stressing screw forms a
force shunt, the sensor must be recalibrated after it is
installed, in order to accurately determine the sensitivity
of the measuring device when it is ready to use.
14.7 Measurements in a force shunt with
CFW/CLP piezoelectric washers
In measurements with CFW and CLP force washers, the
sensitivity of the sensors will vary in accordance with the
mounting. It is therefore necessary to calibrate (adjust)
the force washers once they have been installed.
After mounting, the force washers are in a force shunt,
that is, some of the force no longer flows through the
sensor, but through the pre-stressing device, such as a
CPS pre-stressing set.
A2781-3.1 HBM: public
CMD