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© 2015 Active Research Limited
Important Notices
Actisense
and the
Actisense
logo are registered
trademarks of
Active Research Limited
. All rights are
reserved. The contents of this manual may not be
transferred or copied without the express written
permission of
Active Research Limited
. All other
trademarks are the property of their respective owners.
The
Actisense
NMEA Data Multiplexer / Combiner /
Autoswitch (NDC-4) is intended for use in a marine
environment, primarily for below deck use. If the unit is to
be used in a more severe environment, such use may be
considered misuse under the seller’s guarantee.
The
Actisense
NDC-4 has been certified to comply with
the European directive for Electromagnetic Compatibility
(EN60945), and is appropriately CE marked. Operation of
the unit should be in conjunction with appropriate CE
approved shielded connectors and cabling used in
accordance with the CE directive EN60945. Any EMC
related issues should be reported to
Active Research
Limited
immediately to allow the company to rectify or
resolve EMC related problems in accordance with its
obligations under EN60945.
If the unit is connected such that compliance failure occurs
beyond the company’s control, the company shall not be
held responsible for compliance failure until suitable EMC
guidelines for connection are seen to have been taken.
Notices
The products and specifications described in this guide
may be changed without prior notice. To obtain the latest
.
Active Research Limited
will not be liable for infringement
of copyright, industrial property right, or other rights of a
third party caused by the use of information or drawings
described in this manual.
The NDC-4 must be used in accordance with the
manufacturers instructions.
Active Research Limited
will
not be held responsible for any damage or injury, direct or
otherwise, as a result of failure to adhere to these
instructions.
The NDC-4 does not validate the NMEA data it receives in
any way. Neither the NMEA sentence checksum, nor the
data contained within the NMEA sentence is validated.
Therefore, the electronic device(s) supplying the NDC-4
with NMEA data retain(s) the sole responsibility for the
NMEA data’s validity.
Foreword
Actisense
recognises that instructions are often skipped,
so we have aimed to write this document in an informative,
yet direct manner that will aid the user. We have tried to
cover all the points a typical user may need to know.
Please read all sections before installing and using the
Actisense
NMEA Data Multiplexer product and any
related software programs.
Introduction
The
Actisense
NDC product range developed out of the
requirement to solve two fundamental problems with the
existing marine industry NMEA 0183 communications
standard.
In theory, the NMEA 0183 standard allows any suitably
designed marine electronic device to share its gathered
information with any other device on a vessel.
Unfortunately, there is one very large drawback with this
standard - only one device on a connected network can
actually send data (a single talker), with multiple devices
(determined by the current limit of the sending unit)
listening to that data (multiple listeners).
If the vessel owner has an instrument that ideally requires
the data output of two or more devices, for example a
chart-plotter, then the owner has no alternative but to
settle on connecting only the most important device (that
which supplies the most used information), normally that is
the GPS unit. All other devices cannot be used.
What happens if the owner prefers the vessels gyro
compass heading output to that of the GPS, or requires
that the current depth be displayed on the plotted chart to
help avoid the possible case of running the vessel aground
on a shifting sand bank? The NMEA 0183 standard cannot
supply an answer to those questions as it can handle only
one transmitting device.
These two elementary problems can be solved simply and
easily with the
Actisense
NMEA Data Multiplexer’s very
flexible design approach.
Alternately, if the vessel has two or more identical NMEA
devices (e.g. GPS’s or depth sounders) the system
solution could be to use the NDC-4 as an NMEA Autoswitch
to select the highest priority source.
Full information on the complete
Actisense
product range
can be found on the
Actisense website (www.actisense.
com)
.
Summary of Contents for NDC-4
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