Orolia NAV-7 User Manual

23

Warning: Do not mount the NAV-7 in a position where sea spray can reach it, or
where it may be exposed to direct sunlight

24

DISPLAY ELECTRICAL INSTALLATION

This manual is concerned only with the installation of the NAV-7 and does not cover
the installation of any peripheral equipment connected to the NAV-7 such as
printers, navigational systems or source of NMEA data. For proper installation and
connection of peripheral equipment to the NAV-7 refer to the installation manuals
for these products.

The table below shows the connections that must be made to the NAV-7 for it to
function correctly.

Connection Must connect Optional

Ship’s earth connection

12V or 24 V DC power supply

NAVTEX antenna

Alarm Relay

NMEA or IBS time reference See Note 1 See Note 1
Integrated Bridge/Navigation System

External printer

Note 1: Connecting a time reference (eg a GPS receiver) is highly recommended.

ü
ü
ü
ü

ü
ü

Ship’s earth connection

The earth terminal on the rear of the NAV-7 display must be connected to ship’s
ground by the earth cable supplied. The earth connection should be kept as short
as possible.

Safety Warning

To ensure the best possible protection of the NAV-7 from static electricity

or nearby lighting strikes, the pre-fitted green grounding wire (connected

to the safety earth spade) must be connected to a nearby (hull) electrical

grounding point.

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12V or 24 V DC power connection

A connection must be made to a 12 or 24 V DC supply via a circuit breaker capable
of supplying at least 2 amps. Connection should be to the ship’s radio battery and
be in accordance with GMDSS requirements.

• Connections should be made using the 2 m power cable provided

• Use cable ties to restrain the wiring, and so prevent it becoming weakened

by vibration. The connecting cables should be restrained by securing them
to the rear of the NAV-7 bracket, or to adjacent metalwork

• The screen of the cable should be connected to ship’s earth if possible.

The screen of the cable should not be connected to ship’s battery –ve

Safety Warning

The NAV-7 has been designed and manufactured to be completely safe
when used in accordance with the instructions given in this manual. To
ensure that the complete installation is safe, it is essential that a fuse or
circuit breaker is installed in the power supply cable as described in the

Installation section of this manual.

Isolation between the power supply connections and any other connection to the
NAV-7 is 1 kV minimum.

The DC power source should comply with IMO guidelines for the class of vessel
concerned. National authorities and classification societies may have their own
power supply requirements; these should also be considered.

Signal cable connections

As shown in the table above, the NAV-7 may be connected to different types of
peripheral units including IBS & INS serial ports and printers.

The signal connections are all connected via a serial RS422 type interface; data
rates are selectable at 4800, 38400 or 115200 baud.

In some cases, particularly in retrofit installations, it may not be possible to connect
the NAV-7 directly to the required source/destination for serial data, because some
equipment does not provide the IEC 61162-2 (NMEA) sentences required by the
NAV-7 unit. In such cases a protocol converter is required between the sensor and
the NAV-7. Converters are available from different manufacturers, either as direct
protocol converters or frequently as repeater instruments for the sensor.

26

156

11

Signal line termination

RS422 signal lines may need termination resistors at the far end of the serial cable
connected to the NAV-7, depending on the length of connecting cable and the rate
of data transmission. Both the IBS and the NMEA ports in the NAV-7 have inbuilt
100O termination resistors for both Tx and Rx.

Whether termination is required depends on many factors, particularly the length of
the signal cable and the environment in which the equipment is operating. The
principle is shown in the sketch:

Talker
(NAV-7)

Ground cable
screen at
NAV-7 ONLY

Terminating
resistor

Listener
(may need termination)

There is only one talker per twisted pair; there can be several listeners. The
intention is that terminations must be provided by the devices at the ends of the
line, regardless of whether they are listeners or the talker, and that no other device
should provide a termination.

Since the NAV-7 contains internal termination, it MUST be at the end of the line and
NOT in the middle.

It is good practice to use screened cables in all ship cable installations. Take care to
connect the cable screen to ship’s ground at one end only of the cable, as
connecting at both ends may cause ground loops and interference to the signals.
The cable screen should not be connected to any part of the NAV-7.

Connecting to the IBS serial interface

The display connection cable is supplied ready for
use, and needs only to be plugged into the
appropriate connector on the NAV-7.

Display cable: Six twisted pairs, screened, PVC

sheathed. For lengths to 200 meters, use 0.22 mm2
(7/32); Belden 8106 or equivalent.

The connections to the15-pin socket on the NAV-7 are given below. Note that the
cable screen should not be connected to any part of the NAV-7.

10

15

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156

Power, Alarm & IBS port (2m cable supplied)

Pin

Number

1 IBS_TXA O/P WHITE/BLUE O/P to IBS port
2
3 +V

4 -V (0V) I/P BLUE/RED Ship’s supply -ve
5
6 IBS_TXB O/P BLUE/WHITE O/P to IBS port
7
8 AUX_NC O/P ORANGE/WHITE Alarm Relay NC

9 AUX_NO O/P WHITE/BROWN Alarm Relay NO
10 AUX_COM O/P WHITE/GREY Alarm Relay COM
11
12 IBS_RXB I/P GREEN/WHITE I/P from IBS port
13 IBS_RXA I/P WHITE/GREEN I/P from IBS port
14
15

Connection NAV-7 Cable Colour Notes

(12/24 V DC nominal)

I/P RED/BLUE Ship’s supply +ve

Connecting to the NMEA 0183 interface

If a connection to NMEA 0183 compatible equipment is
required then a suitable cable has to be purchased or
manufactured.

Recommended NMEA 0183 cable: Two twisted pairs,

screened, PVC sheathed. For lengths to 200 meters, use

0.22 mm2 (7/32); Belden 8102 or equivalent.

The connections to the D-Sub 9-pin socket on the NAV-7 are given below. Note that
the cable screen should not be connected to any part of the NAV-7.

NMEA 0183 & printer port

Pin Number Connection Notes

1
2 SER_TXB O/P to NMEA 0183 (printer)
3
4 SER_RXB I/P from NMEA 0183
5
6
7 SER_TXA O/P to NMEA 0183 (printer)
8 SER_RXA I/P from NMEA 0183
9

9

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Alarm relay

The NAV-7 provides a relay connection which can be selected as normally closed
or normally open contacts.

The alarm relay function is configurable from within the setup pages and can be set
(for example) to switch (change state) on receipt of a Search and Rescue
message or for a system fault.

The red LED on the front panel of the NAV-7 mirrors the function of the alarm relay.

Red LED function

LED OFF Alarm relay NC contact closed
LED ON Alarm relay NO contact closed

Recommended cable for connection of alarm relay:

One twisted pair, shielded, PVC sheathed. The required cable dimension is
dependent on the current necessary to activate the alarm indicator.

Built in alarm relay ratings:

Alarm relay absolute maximum ratings

Maximum switching current in
contacts (inductive load)

Maximum switching current in
contacts (resistive load)

Maximum switching voltage 120 V AC or 24 V DC

NAV-7

1.0 Amp

3.0 Amp

N/C
Com
N/O

External connections

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Connector pin-outs

NAV-7 rear panel connections:

15-way D-type – power and IBS port and alarm relay

9-way D-type – NMEA 0183 & printer port

USB connector – for in-field programming

1

/8” Spade terminal – ground pin

• The auxiliary alarm contact is capable of switching up to 24 V DC at up to 1 A

(inductive load). The contacts are not connected to any internal voltages.

• The power supply input is isolated from the case and antenna. It must remain

within the range 10.8 – 31.2 V DC (12/24 V DC nominal) at all times.

TNC RF connector

30

ANTENNA INSTALLATION

Selecting a suitable antenna

The NAV-7 receives transmissions on three frequencies. 518 kHz transmissions are
in International English; 490 kHz and 4209.5 kHz transmissions may be in a local
language.

To receive on all frequencies the NAV-7 must be used with a wide frequency
(400kHz to 5MHz) antenna that covers 518 kHz, 490 kHz and 4209.5 kHz.

If you have purchased the NAV-7 receiver without an antenna then a suitable active
NAVTEX antenna should be used. McMurdo supplies a suitable wide frequency
antenna with the NAV-7 System; this antenna can be purchased separately as Part
No. 905-05.

If the Installer is supplying an alternative antenna, note that the NAV-7 must
be used with a low impedance 50 ohm antenna or an antenna with a 50 ohm
matching network. A mis-matched or high impedance whip or wire antenna

should not be used as the operational range of NAVTEX reception may be greatly
reduced; it is also important that the antenna is capable of reception over the
frequency range specified above.

If a Wire or long whip antenna is used with the NAV-7 it must be fitted with a 50
ohm matching transformer. Take care that the antenna power is disabled – refer to
Setup – Receiver mode for details. A qualified installer should be consulted.