Specifications

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Figure 5.4.1. Definition of the axes and signs of the DWR-MkIII motion sensors.
5.4.4 Inspection of the fluid level
As mentioned in Chapter 2 Maintenance it is important for the stabilized platform and vertical
accelerometer sensor to periodically check the fluid level within the plastic sphere. The fluid
level can be visually inspected through the Perspex lid on the sphere, see Figure 5.4.2. If the
centre of the rubber membrane is pointing upwards, Figure 5.4.2(b), the fluid level is sufficient.
In case the membrane touches the nylon screw, Figure 5.4.2(a), the fluid is too low and fluid has
to be added. Datawell advises to check the fluid level every 3 years. Based on experience the
sensor requires a small refill after 3 to 6 years.
Only fill up the sensor in a clean environment to avoid contamination of the fluid. Do not
insert anything but the original sensor fluid. Datawell will readily supply you with a small
amount. To avoid damage by spilled fluid wrap some tissue paper around the neck of the sensor.
Take off the plastic lid by unscrewing the 6 screw-bolts. Remove the rubber membrane and
pour some fluid into the sensor until the level is about 1.5 cm below the top. Reposition the
rubber membrane without trapping air beneath it. Some deformation of the membrane may be
necessary to do so. Fasten the plastic lid again with the 6 screw-bolts. Remove the tissue and
wipe away all spilled fluid on the outside of the sensor.