Raymarine DSM250, Owner'S Handbook Manual

Page: 31 / 122

Chapter 2: Installation 2-11
WARNING:
If the power connections are accidentally reversed the system will
not work. Use a multimeter to ensure that the input power leads
are connected for correct polarity.
There is no power switch on the DSM250. The unit turns on when
the power cord is attached to ship’s power and plugged into the
POWER
connector on the connector panel.
Note: You should locate the DSM250 so that the power cord can be
easily removed, if necessary. If the sounder is placed in a difficult-to-
reach location, Raymarine strongly suggests installing an on/off
switch on the DSM250 power cord at a point where it is easily acces-
sible.
Ground Connection
It is important that an effective RF ground is connected to the sys-
tem. A single ground point should be used for all equipment. You
may ground the DSM250 by connecting the drain wire (shield) of
the Power Input cable to the ship’s RF ground. If you need to
extend the wire, the extension wire should be an 8 mm braid or
AWG 10 multi-stranded cable.
If your vessel has a dedicated ground strap available, you may
alternatively attach it to the ground wing nut on the rear panel of
the module.
If your vessel does not have an RF system, connect the drain wire
to the negative battery terminal.
The DC system should be either:
• Negative grounded, with the negative battery terminal connected
to the ship’s ground.
• Floating, with neither battery terminal connected to the ship’s
ground.
WARNING:
This system is not intended for use on “positive” ground vessels.
The power cable Ground (earth) connections must be connected
to the ship’s ground as described above.