DESIGNER’S HANDBOOK 4189350049C EN
Page 88 of 206
5.8.2
Connection and cable for NMEA
The RS-422 output may be connected to up to 10 standard NMEA inputs complying with IEC 61162-1
(load >1 kΩ). It is recommended to use a shielded twisted pair cable.
5.8.3
NMEA inputs
The NMEA inputs RX1 and RX3 is galvanic separated and fully complies with the two IEC 61162 standards.
The RX/TX2 (RS-485 port) is used to connect a DEIF wind sensor to an XDi-N wind indicator. This port can also be
configured as either an input or an output, in both cases it will use the NMEA data protocol.
Please note
that the RX/TX2 connections are marked according to the RS485 standard and therefor A and B is
swapped around compared to the NMEA RS422 terminal markings.
For information of supported NMEA sentences please see
“XDi supported NMEA sentences” (separate doc).
5.8.4
NMEA outputs
Only data types used by the selected virtual indicator can transmitted in an NMEA sentence. It requires that the
selected VS profile contains an NMEA output definition for data to be packed in to one or more NMEA sentences
and transmitted via the NMEA output.
Data types may be generated from an AX1 or DX1 module or be received via CAN either using XDi-net data format
or received in a TPDO.
It can also be data received via NMEA that is retransmitted, but in that case, it is often better to use the NMEA
routing function available in XDi-N.
For information of supported NMEA sentences please see
“XDi supported NMEA sentences” (separate document).
Example NMEA from a rudder systems:
All DEIF standard rudder indicators contains VS profiles that will support NMEA output.
The RSA sentence that contains actual rudder angle may be used in a CAN-based rudder system to output the
rudder angle to the VDR.
NMEA for dimming:
When a XDi library contains a product profile where the DDC dimmer sentence is supported, it can control the
dimmer level of the backlight and the day/(dusk)/night colour shift can either be automatic based on dimmer level
(for example shift from night to day at 70%) or separately controlled dimmer level and colour pallet.
When a NX1 or NX2 module is mounted on XDi it is possible to activate the dimmer NMEA output using the DDC
sentence. Depending on the Product profile the DDC can contain the dimmer value and the selected colour pallet.
This will be for the dimmer group that this XDi is a part of.
Example: $IIDDC,,49,,R*1C this DDC sentence contains dimmer level 49% (R = status message)
5.8.5
Contact inputs
The two contact inputs on both NX1 and NX2 module is used for connection of two external pushbuttons.
Via the NMEA setup menu/NX Button setup…, the contact inputs can be configured to control either the two centre
buttons (button 2 and 3) or the left and right button (button 1 and 4).
The external buttons will work in parallel with the buttons on the front. If 4 external buttons are connected to two NX
modules on an XDi 144 N or XDi 192 N then full button operation can be achieved from 4 external pushbuttons.
On XDi dual or multi it is only the two dimmer buttons (button 2 and 3) that can be controlled from the contact
inputs.
The external pushbuttons work in parallel with the front buttons on XDi, so you can just shift between operating the
XDi from the front buttons or via the external buttons.
