Nt920ahr Mkii Manual

NAVITRON SYSTEMS LTD ANALOGUE HEADING REPEATER

NT920AHR MKII INSTALLATION & OPERATION

Osborn House 25e Brockhampton Lane Havant, Hants, U.K. PO9 1JT

Tel: (023) 9249 8740 Fax: (023) 9249 8783 Int. Code: +44 23 Email: [email protected] [email protected]

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NAVITRON SYSTEMS LTD. NT920AHR MKII INSTALLATION & OPERATION

GENERAL Navitron Analogue Heading Repeaters type NT920AHR may be configured for single or multihead display of NMEA 0183 heading data received from proprietary transmission elements (gyro, TMC systems etc.) or as add-on components to most Navitron Autopilot systems. Suitable for 11 – 40Vdc operation, all Repeater heads are electrically identical and fully interchangeable and may be panel or bracket mounted. Bezel outline dimensions of 144 X 144mm allow the unit to be mounted in a DIN144 panel cut out if required. Two inputs are necessary for normal repeater operation (NMEA 0183 heading data and 11 – 40V power supply) beyond which no calibration is required and the card will automatically align with NMEA 0183 data received. Ships head is clearly read from a 120mm diameter-rotating card marked in 1° increments with 5° and 10° divisions also defined. 3 digit numbers (4mm height) are shown at 10° intervals and all scale markings are white on black card background. Variable intensity backlight illumination is controlled from a dimmer pot mounted on the instrument bezel to illuminate all card legends in red or green (installation selectable) for night viewing.

INDEX

Section 1

-

System Overview and Technical Specifications

Section 2

-

Outline and Mounting Dimensions

Section 3

-

Installation notes, Terminal Connections and Card Illumination

Section 4

-

Operational Notes and Audible Signals

Section 5

-

Diagnostic Alarm Features

Section 6

-

Internal Recalibration Procedure

Section 7

-

Connection to NT920DHR


Section 1: System Overview and Technical Specifications. 1.1: System Overview

Switchable (On/Off) 11 - 40Vdc Power Supply from Nav Panel

NT920AHR

1A + VE

8

- VE

7

SMPS (V/REG)

OPTO ISOLATED NMEA 0183

6

5

4

3

2

NMEA 0183 A Input Data from B Heading Source SCR

1

B A

(Linked Directly to Input Data)

SCR

1.2: NMEA Input Stage Isolation 1K5 A 220pF B

1.3: NMEA Input Data Specifications Min Differential Input Voltage Voltage measured at ‘A’ with respect to ‘B’ Input Current at +/- 2V Input Current at +/- 15V NMEA 0183 Format Sentence Types Sentence Update Rate

2V

Logic 1 Logic 0

-15V to + 0.5V +2V to + 15V < 1mA < 10mA 4800 baud, 8 data bits, no parity, 1 stop bit $XXHDT, $XXHDG, $XXHDM, $XXHCC, $XXHSC Min 0.33Hz Max 25Hz

1.4: NT920AHR Performance Specifications Supply Voltage 12V Op. 125mA Illum 160mA Total 285mA Max NMEA Data Resolution Max Following Rate Card Accuracy Operating Temp. Range

Power Consumption 3.9W

11 – 40Vdc 24V Op. 70mA Illum 90mA Total 160mA 0.1° 30° / sec +/- 0.25° -10° to + 60°C


Section 2: Outline and Mounting Dimensions.

NOTE 1: A separate panel mounting clamp bracket is supplied as standard for attachment to the instrument head via reversal of two 6mm screws incorporated in the backplate (item B Fig 3.3)


Section 3: NT920AHR Installation Notes. 3.1: Siting the Unit The Repeater head(s) should be mounted in a sheltered position (wheelhouse etc) free from direct exposure to rain and spray. 3.2: Compass Safe Distance – 1 Metre. 3.3: Cable Requirements Screws ‘A’ 8 Off

Fuse (1A)

Screws ‘B’ 2 Off (Reverse for use with Panel Mount Bracket)

11 – 40Vdc Power Supply 2 Core Screened 16/02mm

NMEA 0183 Data To Other Users 2 Core Screened 7/02mm

NMEA 0183 Input Data 2 Core Screened 7/02mm

Fig 3.3 View on NT920AHR Backplate 3.4 Terminal Connections (i)

Remove the backplate (8 screws ‘A’) and withdraw the backplate assembly complete with the two trailing plug connectors.

(ii)

Enter the power supply and data cable(s) into their respective glands and tighten prior to connection of the cable screens and cores. (See FIG 3.4 and Note 1). Note1: These screens must not be connected to the earth stud but should be insulated and connected to terminals 3 & 4 as shown. ●

1

2

3

4

5

6

Earth Stud (Power supply cable screen only)

A

NMEA 0183 Out

Fig 3.4

8

●

-VE +VE

SCR SCR

B

7

B

A

NMEA 0183 In

11 – 40 Vdc Power Supply


Section 3: NT920AHR Installation Notes (Continued). 3.5:

Card Illumination The NT920AHR is equipped with a front panel dimmer control to provide variable intensity card illumination in Red or Green (as preferred) for night viewing. Red/Green illumination is defined by the position of the two links shown in Fig 3.5.

Fig 3.5 3.6:

Refitting the backplate

(i)

Check that the backplate gasket is in place and return the two 2 way plugs to their appropriate P.C. Board mounted connectors as shown in Fig 3.5.

(ii)

Safely arrange the internal wiring before replacing and tightening the backplate screws. The Heading Repeater is now ready for use.


Section 4: Operating Notes and Audible Signals. 4.1:

General Operation Provided that the Heading Repeater has been connected in accordance with Section 3 and is in receipt of NMEA 0183 heading data, the card will automatically align with the data received and will respond to subsequent heading changes, with an accuracy of +/- 0.25° accordingly.

4.2:

Card Illumination Control A dimmer control is mounted on the front of the instrument to vary the intensity of card illumination for night viewing in Red or Green (Full clockwise = max illumination).

4.3:

Automatic Alignment at Power Up At power up (11 – 40Vdc supply ON) the card will rotate in a counter clockwise direction searching for automatic alignment with the NMEA data received. This process may take up to 15 seconds beyond which an audible signal will be emitted to confirm operational status or a fault condition as appropriate.

4.4: (i)

Audible Signals Operational Status Confirmed Following automatic alignment of the card as described in 4.3, the heading repeater will scan the NMEA data received and will lock on to a sentence type in order of priority as follows: HDT = 3 single bleeps over 5 seconds following automatic alignment HDG = 3 double bleeps over 5 seconds HDM = 3 series of 3 bleeps over 5 seconds HCC = 3 series of 4 bleeps over 5 seconds HSC = 3 series of 5 bleeps over 5 seconds The foregoing audible signal following automatic alignment confirms normal operation and the sentence type on which operation is based.

(ii)

No NMEA Data / NMEA Data Fail Alarm In the event that no NMEA data is available the heading repeater will alarm both audibly and visually for a period of 10 seconds. This alarm is in the unmistakeable form of equally spaced bleeps accompanied by flashing illumination. After 10 seconds, the audible alarm will cease automatically but the illumination will continue to flash until the dimmer control is turned fully counter clockwise.

N.B.

If NMEA 0183 data is subsequently restored the heading repeater will recover automatically and confirm sentence as described in 4.3 and 4.4 (ii).


Section 4: Operating Notes and Audible Signals (Continued). 4.4:

Audible Signals

(iii)

Internal Error Alarm Self-test features within the heading repeater continuously monitor the integrity of the instrument, which will emit an audible alarm if an internal fault is detected. This alarm is signified by Morse code signal IE (Internal Error) repeated 3 times over a period of 5 seconds, i.e. ●●…●, ●●…●, ●●…●. After a further period of 5 seconds, the instrument will again emit a Morse code letter signifying the type of internal failure detected.

N.B.

In the event of internal error failure, refer to section 5 – Diagnostic Alarm Features.


Section 5: Diagnostic Alarm Features. 5.1:

The NT920AHR is an intelligent heading repeater which, in addition to monitoring heading data received, continuously monitors its own internal functions enabling the operator to be warned of any potential defect. In the event that an internal error is detected, the instrument will emit an audible alarm in Morse code using the letters IE (internal Error) repeated 3 times over a period of 5 seconds i.e. ●●…●, ●●…●, ●●…●. Any internal error detected and signalled will fall into one of two categories: FATAL NON-FATAL

Operation is suspended. Operation continues without internal backup.

In all cases, an Internal Error (IE) signal will be followed after a period of 5 seconds by a second signal identifying the error type. This will again be a Morse code letter repeated 3 times over a period of 5 seconds as follows: IE (Internal Error alarm) followed after 5 seconds by: F (Feedback) V (Volatile)

5.2:

— ●, ●● — ●, ●● — ● (FATAL) ●●● —, ●●● —, ●●● — (NON-FATAL) ●●

Fatal Error Alarm (F) IE followed by ‘F’ after 5 seconds. If a fatal error alarm is generated, the NT920AHR should be switched OFF (powered down) and retried (power up). If the fatal alarm is repeated, qualified assistance will be required in conjunction with further diagnostic aid available from internally mounted LED’s – see section 5.4.

5.3:

Non-Fatal Error Alarm (V) IE followed by ‘V’ after 5 seconds. In this condition, the repeater will continue to function but may exhibit inaccuracies due to limitations imposed by the failure of internal backup data. See section 5.4 for further diagnostic aid.

5.4:

Diagnostic LED’s Two diagnostic LED’s are situated on the NT920AHR P.C. Board and are visible when the backplate is removed (LED’s 7 and 10 on Fig 5.4). LED 9 is also useful for reference purposes if a fault condition exists thus an internal error (IE) alarm may be identified more closely as follows: -


Section 5: Diagnostic Alarm Features (Continued).

Fig 5.4 5.5:

5.6:

Normal Operation LED 7 –

Off.

LED 9 –

Watchdog timer – Permanently On.

LED 10 –

Flashes coincidental with NMEA input sentence end.

Fatal Error Conditions

(i)

LED 7 and 10 flashing in sync at approximately 1Hz indicates auto alignment fault.

(ii)

LED 7 and 10 permanently On indicates rotational failure of the mechanical assembly (card, gears, motor etc.). Consult factory for assistance.

5.7: (i)

Non-Fatal Error Conditions LED 7 flashing at 1Hz, LED 10 flashing normally indicates failure of non-volatile memory.

(Heading repeater will continue to function but recalibration should be attempted in accordance will section 6.)


Section 6: Internal Recalibration Procedure. 6.1:

General Calibration Note During normal operation, when the NT920AHR is switched On (powered up) the heading repeater card will automatically align with NMEA 0183 data received unless: -

(i)

No NMEA 0183 data is available. (Alarm will sound accompanied by flashing illumination as described in Section 4.4 (ii) and the card will stop at 360°, as a function of factory calibration).

(ii)

An internal error (IE) alarm has been generated in accordance with section 5.1

(iii)

Heading Repeater card or associated components have been replaced and a continuous fixed error exists between the NMEA 0183 data received and the heading displayed by the card. (I.e. effectively coefficient A error). The following calibration procedure is applicable when attempting to restore coefficient A correction data held internally in non-volatile memory in the event of memory corruption confirmed by IE Alarm followed by Morse letter ‘V’ (see section 5.1) or recalibration following repair (section 6.1 (iii)).

6.2: (i)

Coefficient A Calibration Remove the NT920AHR backplate to expose switches SW1, SW2 and SW3 as shown in Fig 6.2.

Fig 6.2


Section 6: Internal Recalibration Procedure (Continued). (ii) (iii) (iv)

Power up the heading repeater and hold down SW3. The repeater card should now rotate and stop and 360°. With SW3 held down, use SW1 or SW2 to adjust the card indication to 360° as follows: SW1 SW2

(v) (vi)

Increases heading indication Decreases heading indication

Release SW3 and SW1 / SW2 when 360° is obtained. Power down the heading repeater (switch Off) and power up again (switch On). Coefficient A error and/or IE (V) alarm should now be cancelled confirming restoration of non-volatile memory data.

(vii)

Power down and replace backplate. Calibration is now complete and heading repeater is ready for normal operation.


Section 7: Connection to NT920DHR (Navitron Digital Heading Repeater) 7.1:

Application Note Each analogue Heading Repeater (NT920AHR) is capable of supporting up to 3 digital heading repeaters type NT920DHR via a 4 way connector situated on the NT920AHR P.C. Board (see Fig 7.2). This connector provides the custom Navitron serial data required by the digital heading repeater (DHR), which will not accept NMEA 0183 data directly. All NMEA 0183 data connections are therefore confined to the Analogue Heading Repeater (NT920AHR) in the standard manner. (Section 3.4 refers).

NT 920 AHR

11 – 40Vdc Power Supply

NMEA Data In

NT 920 DHR

Navitron Serial Data for up to 3 x NT920DHR

Fig 7.1 7.2:

NT920AHR Connections

(i)

Power Supply and NMEA 0183 data cables should be connected as standard and as shown in Section 3.4.

(ii)

An additional 4-core cable should be connected to Terminals 5 to 8 as shown in Fig 7.2.

4-Core Cable Connections

5 – Red (+12V) 6 – Blue (0V) 7 – Green (Clock) 8 – Yellow (Data)

Fig 7.2


Section 7: Connection to NT920DHR (Navitron Digital Heading Repeater) - Continued. 7.3:

NT920DHR Connections

(i)

Separate the NT920DHR case and bezel to expose the internal P.C. Board (Fig 7.3).

(ii)

Position LINK 1 between TP1 and TP2

(iii)

Connect 4 core cable from NT920AHR to NT920DHR terminal block N°’s 4 to 7 and link terminal 3 to 5 as shown.

TP1 TP2 TP3

1 2 3 4 5 6 7

4 Core Cable from NT920AHR

(iv)

Blue (0v) Red (+12v) Yellow (Data) Green (Clock)

Reassemble the case and bezel assembly The NT920DHR is now ready for use with the NT920AHR.

Link 1

Nt920ahr Mkii Manual

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