NDC comm NDC-3 - Manual (Page 8)

Page 8 © 2005 Active Research Limited
NMEA 0183 Inputs
The NMEA 0183 differential opto-isolated inputs are
designed to handle a variety of NMEA 0183 device
output specifications. Please determine (from device
manufacturer’s information) if the device(s) required to
be connected to the Actisense™ NDC-3 conforms in full
to the NMEA 0183 network communication standard. If it
does not, the flexible Actisense™ NDC-3 inputs should
still be capable of interfacing with the device, though this
is not guaranteed.
The diagram above shows a typical installation with both
fully compliant NMEA devices with differential inputs/
outputs, and non-differential output devices that output
NMEA using the ground line as the “ NMEA -” line.
NMEA Talker devices 1, 2 and 4: These devices
conform in full to the NMEA 0183 standard. Devices
1 and 4 share the same connection ID’s as the
Actisense™ NDC, so connection is a simple matter of
matching the ID’s (refer to figure 2). Device 2 uses the
RS485 convention connection ID’s. Simply connect ‘ A‘
to ‘ +/A‘ and ‘B’ to ‘ -/B’ (refer to figure 2).
NMEA Talker device 3: This device does not conform
completely to the NMEA 0183 standard. However, by
connecting ‘ +‘ to ‘+/A‘ and its ‘G/Ground’ to the NDC
“ -/B” the NDC should be able to receive the NMEA data
correctly.
NMEA 0183 Output
The NMEA 0183 buffered output is capable of driving up
to 15 NMEA 0183 fully compliant listening devices, or a
mixture of NMEA 0183 devices and a Personal Computer
(PC) communication port.
NMEA Listener device’s B and C: These devices
conform in full to the NMEA 0183 standard and their
connection ID’s match that of the NDC.
Personal Computer: Whilst the RS-232 port is designed
for connection to a PC, the NMEA 0183 output is also
capable of being read by most PC’s. Simply connect ‘ +’
to ‘ Rx’ and ’G’ to ‘Gnd’ on a standard D-type (probably
male) connector.
NMEA Listener device A: This device does not
conform in full to the NMEA 0183 standard. However,
by connecting ‘ -‘ to ‘-/B‘ and ‘G/Ground’ to ‘Gnd’
the device should be able to receive the NMEA data
correctly, though this is not guaranteed.
Note:
1. Wire colours are for guidance only.
Connecting to NMEA devices
Figure 2 – NMEA 0183 connections
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