Norsonic Nor1212, Instruction Manual, Page: 17 / 26

Norsonic Nor1212
User Guide
13
5 Maintenance
The need for maintenance depends largely on the environmental
conditions where the microphone system is used. For most semi-
permanent applications, the maintenance is normally either done before
the start or after the end of a measurement. During the measurement
normally only periodic checks of the calibration are needed.
Before the start of a new measurement, remove the windscreen and verify
that it is not contaminated with dust or dirt. The windscreen may be
washed by hand using standard washing up detergents only. Ensure that it
has been thoroughly rinsed in clean water and is completely dry before it
is remounted. Do not use excessive heat for the drying: 60ºC maximum. If
used outdoor most of the time, we recommend replacing the windscreen
every other year, spare part Nor4520. However in some locations, near to
chemical complexes or in coastal installations it may be necessary to
replace the windscreen earlier.
Remove the upper protection part and verify that the mesh covering the
acoustic ports is clean and free from dust. You may inspect the mesh by
holding it in front of a light source; rotate the upper protection part and
look through the holes. Use a soft brush to wipe off any dust or detritus. If
heavily polluted, peel off the mesh and replace it with a new; spare part
number Norsonic 0896000. The mesh comes with an adhesive. When you
mount a new mesh, ensure that the splice is placed midway between the
acoustic ports! See figure 2.1.
If you use the desiccator, this needs to be dried at regular intervals. This
may be attained by placing the desiccator for a few hours at an elevated
temperature, e.g. 100ºC. Do not heat beyond 130ºC as this will harm the
device. The desiccator TA202 has a small window where you can see the
silica gel inside, see figure 5.1. When dry, the gel has a light blue colour.
This colour changes to milky-white when the gel is wet and cannot absorb
more water.
Figure 5.1 Desiccator
TA202