Autohelm GPS & NAVDATA Operation and Installation
Autohelm and SeaTalk are registered Trade Marks of Nautech Limited Autohelms policy of continuous improvement and updating may change product specifications without prior notice Copyright Nautech 1993
Package Contents The following items are included in the ST50 Plus GPS and Navdata packages: 1 . ST50 Plus control head 2. Fixing studs (2 off) 3. Thumb nuts (2 off) 4. Control head cover 5. Power cable 6. NMEA cable 7. Security sticker 8. Fitting template 9. Operation and Installation handbook 10. Worldwide Service Centre handbook 11 .
Contents Introduction .. ..... ..... . .......... ..... ........... ... . .... ..... ..... ..... ......... 1 Chapter 1: Control Head Installation ..... . ... . .............. . .... ...... ... 3 1.1 Siting . ..... .. .. ... .. .. .. . . . .. .. .. ... .. .. .. ....... .. .. .. .. .. . .. .. .. ... .. .. .. .. .. . 3 1.2 Mounting Procedure . . .. .. .. ... .. .. .. ......... .. .. ... .. .. .. .. . .. .... .... .. . 4 1.3 Power Supply (stand-alone operation) . .. .. .. ... .. .. .. . . . .. .. .. .......
Introduction The ST50 Plus GPS and Navdata instruments are repeaters thatreceive positional fixes via either NMEAor SeaTalk, from the GPS satellite system or the Loran/Decca beacon network . The GPS system comprises of 24 satellites (operating globally 24 hours a day) grouped into six separate orbits . Up to 5 of the 24 satellites are tracked at any one time, and the difference between the unique signal from each satellite is used bythe ST50 Plus GPS receiver to calculate your exact position.
Chapter 1 : Control Head Installation 1 .1 Siting The ST50 Plus GPS/Navdata is designed for above or below deck installation where it is : " Easily readable by the helmsman " Protected against physical damage " At least 230mm (9in) from a compass " At least 500mm (20in) from radio receiving equipment " Accessible from behind for ease of installation and cable running Caution: To prevent moisture forming on the display window, the ST50 Plus GPS/Navdata 'breathes' through a small vent in the cable boss.
1 Cable boss 2 Fusing studs 3 Thumb nuts 4 Gasket 1.2 Mounting Procedure 1 . Make sure that the selected location is clean, smooth and flat. 2. Apply the self-adhesive template (supplied)to the selected location and markthe centres for the fixing studs (2) and the cable boss (1). 3. Drill two 4mm (5/32in) clearance holes for the fixing studs (2) through the bulkhead . Remove the template. 4. Cutthe clearance hole for the cable boss (1) using a 50mm (2in) diameter cutter . 5.
Bracket Mounting The ST50 Plus GPS/Navdata can, as an alternative, be bracket mounted using theAutohelm Mounting Kit (Catalogue No. D130) . Note: Because the instrument breathes through the vent in the rear case, this bracket is for interior use only. Flush Mounting A flush mounting kit is available for installations where a flush mount is required or more desirable . Full installation instructions are provided with the kit (Catalogue No. D187).
1 .3 Power Supply (stand-alone operation) 1 . Connect the 2m (6ft.) power supply cable to the distribution panel. 2. Cut the cable to length and connectthe red wire to the +12V terminal and screen to the OV terminal. 3. Cut back and insulate the yellow wire. 4. Protect the circuit with a 5Acircuit breaker . Longer runs to the vessels power supply can be made using one of the SeaTalk Extension Cables. 1.
1 .5 Connection of Separated Instruments Separated instruments can be connected using one of the range of SeaTalk Extension Cables. These cables are supplied with a SeaTalk connector fitted to each end . A junction box can be used to join the cable if it is cutfor easier routing or shortening . If preferred, any 2 core, screened cable conforming to the following specification may be used instead of the SeaTalk cable. " 22 AWG, 2 core screened cable with a minimum copper area of 0.5mm2.
1 .3 Power Supply (stand-alone operation) 1. Connect the 2m (6ft.) power supply cable to the distribution panel . 2. Cut the cable to length and connect the red wire to the +12V terminal and screen to the OV terminal . 3. Cut back and insulate the yellow wire . 4. Protect the circuit with a 5A circuit breaker. Longer runs to the vessels power supply can be made using one of the SeaTalk Extension Cables . 1 .
1.5 Connection of Separated Instruments Separated instruments can be connected using one of the range of SeaTalk Extension Cables. These cables are supplied with a SeaTalk connector fitted to each end. A junction box can be used to join the cable if it is cut for easier routing or shortening. If preferred, any 2 core, screened cable conforming to the following specification may be used instead of the SeaTalk cable. " 22 AWG, 2 core screened cable with a minimum copper area of 0.5mm2.
1 .6 Ring Connection Installations with a large number of instruments on a SeaTalk bus may require a second ring-main connection to the power supply breaker to prevent excessive voltage drops.
1.8 Connection to a Position Transducer The ST50 Plus GPS/Navdata receives basic navigation information from a position transducer via NMEA. The position transducer should be connected to your SeaTalk system in one of the following ways: 1 . Directly to the ST50 Plus GPS/Navdata NMEA port. 2.
Note: When used with a Navcenter, the ST50 Plus Navdata/GPS can only be used in 'Repeater ' mode (refer to Chapter 5, Calibration for details). Refer to the Navcenter handbook for accepted NMEA sentences. The Navdata is also capable of receiving navigation information directly from a Navstar 2000D Decca system . Connection is identical to NMEA but the instrument must be set up in Calibration to receive the special Navstar data format (refer to Chapter 5).
Chapter 2: Fault Finding and Maintenance 2.1 Fault Finding All Autohelm products are, prior to packing and shipping, subjected to comprehensive test and quality assurance programmes. However, if a fault arises with the ST50 Plus GPS/Navdata, the following table will help to identify the probable cause and provide the most likely cure. Fault Cause Action Instrument display blank. No supply. Check supply . Check cabling and security of SeaTalk connectors . Check fuse/breaker . Return unit for repair .
2.2 Maintenance Instrument Certain atmospheric conditions may cause condensation to form on the control head window. This will not harm the instrument and can be cleared by increasing the illumination setting to Level 3. Chemical and abrasive materials must not be used to clean the ST50 Plus GPS/Navdata instrument ; if it is dirty, clean with a soft, damp cloth . Transducer Refer to the Installation and Maintenance instructions supplied with the transducer.
Chapter 3: Operation The Navdata/GPS allows you to enter and store upto 99 waypoints . A route can be constructed as any number of sequential waypoints (1, 2, 3 4) or, aftematively, a single sail plan of up to 10 waypoints selected in any order (e.g. 2, 4,1). Waypointstracked sequentially Waypoints tracked using Sail Plan The features described above, together with all the other operational features of this instrument, are covered in this section .
3.
Display Key Notes Position Totoggle longitude and latitude, press V or ^. Longitude and latitude can be displayed at the same time by pressing V and A together momentarily . To return to the individual longitude and latitude displays, press V or ^ . COG/SOG Press V or ^ to toggle between COG/SOG (Course Over Ground/Speed Over Ground) and COG/BTW (Course Over Ground/Bearing toWaypoint) .
3.2 Waypoint Display and Entry This section describes how to : set up a waypoint, select a waypoint as a target waypoint, change a target waypoint, reverse a route of waypoints for a homeward journey and, finally, how the instrument can automatically or manually advance to the next waypoint.
3.3 Sail Plan Sail Plan allows you to select upto 10 of a possible 99 waypoints and arrange them in any order, e .g . 7,10,15 etc . Once sail plan has been selected and track engaged (refer to Chapter 3 .2), the vessel will follow the selected waypoints .
Changing an Existing Sail Plan Waypoint Number The waypoint number assigned to a selection can be changed at any time by carrying out the following actions: 1 . Cycle DISPLAY until SEL and WPT is displayed Note: Plan must be set to 1 to view this display. 2. Press ^ to choose the required SELection. 3. Carry out actions 4, 5 and 6 above. 4. Press DISPLAY or TRACK to return to normal operation. Turning Off a Sail Plan Waypoint Selection A Sail Plan waypoint selection can be turned off as follows: 1 .
Track Control Selecting a Target Waypoint Once the latitude and longitude of a waypoint has been entered, or a sail plan has been set up, the waypoint can then be selected as a target waypoint: 1. Press TRACK to display waypoint information . 2. Display the intended target waypoint number (LAT or LONG) using V or ^. Note: Ifthe sail plan is selected, the first waypoint will automatically be displayed . 3. Press TRACK to select track control .
The following navigation information will be displayed on the GPS/Navdata and transmitted onto the SeaTalk bus: " Cross Track Error (XTE) " Bearing to Target Waypoint " Distance to Target Waypoint " Target Waypoint Number " ETA at Target Waypoint " VMG to Target Waypoint Press TRACK to exittrack control . Transmission of cross track error (XTE) onto the SeaTalk bus will stop, but waypoint distance, bearing and number will continue .
Route Reversal Once a passage is complete the route or sail plan can be reversed for use on the homeward passage . To reverse a route: 1 . Press TRACK to enter the waypoint display . 2. Select the lastwaypoint number in the route or sail plan using V and ^. 3. Press TRACK to enter track control. 4. Press V within 2 seconds to reverse the route or sail plan direction . The display will show ROUTE/REVERSE for 10 seconds.
3.4 Man Overboard Man Overboard stores the current position and calculates the distance and bearing to return to that point. The distance and bearing to the 'Man Overboard' position v4 replace the target waypoint distance and bearing display .
3.5 Anchor Watch Anchor Watch stores the current position and calculatesthe distance and bearing tothat point. The distance and bearing to anchor replaces the waypoint distance and bearing display. Note: Remember that, when selective availability (refer to the GPS position transducer handbook for details) is active, the alarm range should not be set to less than 0.08nm as positional errors will trigger the alarm.
3.6 Dead Reckoning Mode If the ST50 Plus GPS/Navdata fails to receive a position signal it will sound an alarm and display 'NO DATA' for 10 seconds. If the vessels speed and heading is available on the SeaTalk bus, the GPS/ Navdata will automatically calculate a 'dead reckoned' position using the SeaTalk data. The display will automatically change to display a 'DR' (dead reckoned) message . Ifthe position signal returns, the GPS/Navdata will automatically start to operate normally .
3.7 Operation with SeaTalk Autopilots When a SeaTalk autopilot is included in the system, track control is available in the cockpit using the autopilot control unit. The autopilot control unit allows you to: " put the GPS/Navdata into track control " redefine your desired track from the current position to the target waypoint " advance your targetwaypoint along your pre-planned route " look atthe bearing and distance to target waypoint, target waypoint number and cross track error.
3.8 Operation with a Navcenter The Navcenter is a much simpler and more powerful way of setting waypoints and routes . This is due to its ability to display them graphically on an electronic chart. For this reason, all waypoints and route planning should be done on a Navcenter wheneverthere is one included in the system . When a Navcenter is included, the ST50 Plus GPS/Navdata should be set to REPEAT mode (refer to Chapter 5, Calibration).
3.9 Position Correction If you plotyour current position on a chart that uses a different datum to that set in the position transducer you may notice an error. If an accurate current position is known a correction can be entered to allowfor the different chart datum. Radio position transducers (Decca and Loran) suffer from radiowave interference which can be caused by atmospheric changes, local land masses and time of day. This interference produces positional errors.
3.10 Display Contrast The display contrast can be adjusted to achieve optimum legibility at any angle. 1 . Momentarily press DISPLAY and TRACKtogether. 2. Press V or ^ to increase or decrease the contrast setting (the range is between 1 and 15). 3. Press DISPLAY and TRACK together momentarily to store the selected contrast setting . Ahigh setting will suit installations where the control head will be viewed from above .
Chapter 4: CODE Lock Security The ST50 Plus range incorporates an anti-theft feature called 'CODE Lock' . Designed to protect individual instruments or complete systems in vulnerable areas, 'CODE Lock' is a four digit number that you programme into the permanent memory of a selected 'master' instrument. Note: A 'master' instrument is a digital unit on which the code number can be entered, and then, if part of an integrated system, transmitted to other ST50 Plus intruments .
Mode 3: 'CODE Lock' input at Power-On (page 30) In the 'Power-0n mode', the ST50 Plus is configured so that you have to enter the four digit number on a 'master' digital instrument every time the system is switched on . Until this number is entered the instrument(s) will not operate. This mode is particularly useful when you are unable to position a 'master' instrument below decks and, therefore, all the vessels valuable instrumentation is left in a vulnerable area .
Once Only Entry Action Display Shows 1 Press and DISPLAY and TRACK together for 4 seconds CAL after 2 seconds and Z146VXX after 4 sec .
On Power-Up Action Display Shows 1 Press and DISPLAY and TRACK together for 4 seconds CAL after 2 seconds and Z146VXX after 4 sec .
Chapter 5: Calibration The ST50 Plus GPS/Navdata can be set to accountfor local time differences, position correction, magnetic variation, and other set-up and installation related parameters .
5.
Initial Calibration Notes Operating Mode For normal operation the operating mode should be setto 'MASTER' ; this allows waypoints to be entered. If the system includes a Navcenter, or you wish to usewaypoints entered into another manufacturer's equipment, the operating mode should be set to 'REPEAT. In this mode the GPS/Navdata provides cockpit repeater capability only . Data Port Format This should be set to NMEA for use with theAutohelm GPS receiver or Navstar if usingthe Navstar 2000D Decca receiver.
5.
Intermediate Calibration Notes Software Version This display shows the unit part number followed by the software version number. Security Code Full details on how the 'CODE Lock' security featureworks, is setup and stored are given in Chapter 4. Exit Intermediate Calibration Press and hold DISPLAY and TRACK for 2 seconds to return to normal operation.
5.
Extended Calibration Notes All of the extended calibration screens are adjusted using the V and/or ^ keys. Calibration On/Off This feature allows you to protect your selected settings against accidental change . When lock is enabled the initial and intermediate calibration settings cannot be modified . CAL 1 = Calibration unlocked, i.e. normal access CAL 0 = Calibration locked, i.e. no access Once locked, calibration can only be unlocked by entering extended calibration and selecting calibration unlocked.
Chapter 6: General Specification Dimensions : 110 x 110mm (4.33 x 4.33in) Power supply : 10 to 16V Power consumption : 30ma (normal) 100ma (illumination on) Temperature range : 0 to 70 deg .
Autohelm A Raytheon Company Nautech Limited, Anchorage Park, Portsmouth P03 5TD, England Telephone (0705) 693611 .
