Specifications

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paper bag back into the plastic bag. To prevent unnecessary moisture saturation of the drying
agent, close the hatch whenever the buoy is not in use. The bags are fixed to the plywood boards
with Velcro straps.
Four plywood boards hold down the batteries in the outer ring and the aluminium lid on
the aluminium can or the batteries inside the can. To hold down the batteries inside a plywood
disk with four legs is used. Fold the disk and unscrew some legs if you need to take it out.
5.9.9 Test box, step-up converter and connector pin assignment
A test box is mounted inside the hull or integrated in the buoy's main hatchcover cable to
monitor battery sections and, in case of the 0.9 m DWR-MkIII, analog sensor outputs, see
Figures 5.10.1-5.10.7. Each battery section may be tested by applying a voltmeter over the point
“+Bat” and the respective section point “A”, “B”, “C”, etc. These points are interconnected
through diodes to point “−Bat”.
The standard power supply module only accepts battery voltages in a certain range. A
series of 4 cells, as in the DWR-G 0.4 m, produces a series voltage that already lies below this
range when the batteries are fresh, let alone when they are nearly exhausted. Therefore, a step-
up converter is integrated in the test box. The battery voltage before stepping-up is measured at
the points on either side of the connector.
Table 5.9.3 displays the scaling of the various analog signals. Note that the sine of the
pitch and roll angles is actually measured and not the angle itself. The output resistance of the
analog outputs is 4.7 KΩ.
Finally the abovementioned figures also show the pin assignment of the main hatchcover
connector.
Table 5.9.3. Scaling factors of the analog signal on the test box.
Signal Scaling
A
v
4000 mV/10.0 m/s
2
A
x
, A
y
4000 mV/9.82 m/s
2
H
x
, H
y
, H
z
70 mV/A/m
Pitch, roll 4000 mV/sin(90º)
5.9.10 Hatchcover and option ports
The hatchcover closes the buoy and several communication antenna and sensor options mount
onto the hatchcover. It is fastened with 24 hexagon socket screw-bolts in 24 countersinking
holes. In case of partial vacuum in the hull, the hatchcover may be lifted by screwing one of the
hexagon socket screws in the additional threaded lifting hole. When closing the hatchcover,
carefully inspect the rubber sealing ring and the groove in the flange for dirt, cuts and scratches.
Take care that the rubber sealing ring is properly fitted in the groove before positioning the
hatchcover. Do not over-tighten the screws-bolts, especially Cunifer10 is vulnerable for abuse.
Use of grease is not advisable. Figure 5.9.2 depicts the top and bottom side of the hatchcover.
The hatchcover of the 0.4 m buoy does not have option ports. It has 8 screw holes. All antennas
are permanent.
On the bottom side of the hatchcover the electronics unit is fixed with three removable
feet. The top side either has two or three option ports labelled HF and GPS. The possible third
port remains unlabelled and is used for GSM or satellite link. Each port receives the respective
communication antenna and the construction is similar to that of the hatchcover and the hull
flange. Please read the above paragraph on the rubber sealing ring and cleaning again. When
placing the respective insert an electrical coaxial connection is made simultaneously. Unused
ports should be closed with a blind flange. All ports and connectors are waterproof. Hence, even
with unclosed ports or damaged and leaking inserts no water can enter the hull. Nevertheless,
short-circuiting the connector may affect the buoy operation. The hatchcover handles are solely
intended for lifting the hatchcover with electronics unit and antennas. They must not be used for
lifting the buoy.