HBM CMD Serie Bedienungsanleitung Seite 72

Tips for piezoelectric measurement technology
70
If the insulation resistance of the cable between the
sensor and charge amplifier is too low, the measuring
chain will drift, as the charge can drain away via the
too low insulation resistance. Insulation resistances
12
 are considered good.
>10
To keep the piezoelectric measuring chain drift low, all
plugs and sockets must be kept clean at all times.
Under no circumstances touch open contact surfaces
with your fingers, or allow oil on them, as this can
reduce the insulation resistance.
So we recommend that protective caps should be left
on the sockets of the sensors and charge amplifier
until the sensor or charge amplifier is connected. If
you disconnect, you should screw the protective caps
back on again.
- Use high‐quality connection cables.
Piezoelectric sensors must be connected to the
charge amplifier by low‐noise, high‐insulation, coaxial
cables.
Important
The cable must not be damaged. Should it be damaged,
it must be replaced, as it is not possible to repair it.
If however, despite every precaution, sockets still get
contaminated, you can clean them as follows:
S Unscrew the plug.
S Dry wipe the white surfaces of the socket with a
cleaning pad (e.g. HBM ordering number
1-8402.0026)
S Spray the socket with pure isopropanol, e.g. IPA200
from RS Components.
A2781-3.1 HBM: public
CMD