Raymarine DSM250 User Manual

[Page 1] Raymarine DSM250

DSM250 Digital Sounder Module Owner’s Handbook Document number: 81211_1 Date: December 2002 ...

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[Page 3] Raymarine DSM250

DSM250 Digital Sounder Module iii DSM250 Digital Sounder Module Owner’s Handbook December 2002 Intended Use Raymarine DSM250 Digital Sounder Modules provide echo sounder data that can be displayed on Raymarine PLUS Radar, Chartplotter, or Fishfin...

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iv DSM250 Digital Sounder Module EMC Conformance All Raymarine equipment and accessories are designed to the best industry standards for use in the recreational marine environment. The design and manufacture of Raymarine equipment and acces- sories ...

[Page 5] Raymarine DSM250

DSM250 Digital Sounder Module v Throughout this handbook, the dedicated (labelled) keys are shown in bold capitals; for example, MENU. The soft key func- tions, menu names and options are shown in normal capitals; for example, SCREEN. Operating pro...

[Page 6] Raymarine DSM250

vi DSM250 Digital Sounder Module Europe Raymarine Ltd Anchorage Park Portsmouth, Hampshire England PO3 5TD Telephone: +44 (0) 23 9269 3611 Fax: +44 (0) 23 9269 4642 Or, you may contact us on the World Wide Web at: www.raymarine.com This product cont...

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DSM250 Digital Sounder Module vii Contents SAFETY NOTICES ........................................................iii EMC Conformance .......................................................... iv Warranty ...............................................

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viii DSM250 Digital Sounder Module EMC Conformance ......................................................2-15 Chapter 3: Getting Started ....................................................... 3-1 3.1 Introduction ......................................

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DSM250 Digital Sounder Module ix Date and Time Settings ................................................ 4-11 GPS SOG/COG Filter ..................................................4-12 Compass Set Up .....................................................

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x DSM250 Digital Sounder Module Using Zoom .................................................................5-24 Chapter 6: Sonar Mode Operation ........................................... 6-1 6.1 Introduction ..........................................

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Chapter 1: Overview 1-1 Chapter 1: Overview 1.1 Introduction This handbook describes the DSM250 Digital Sounder Module. The DSM250 receives sonar signals from a transducer mounted in the water and transmits data via hsb 2 to a Pathfinder PLUS Rad...

[Page 12] Raymarine DSM250

1-2 DSM250 Digital Sounder Module The DSM250 features dual frequency (200 kHz and 50 kHz) operation and—depending on the transducer installed and condi- tions—up to 1000 watts RMS output power and performance from 3 ft (1m) up to 5000 ft (1700 ...

[Page 13] Raymarine DSM250

Chapter 1: Overview 1-3 Chapters 6 provides detailed information for operating the sonar functions - selecting depth range limits, adjusting gain, color and STC, setting alarms, using the VRM marker, marks and man over- board. Chapter 7 provides in...

[Page 14] Raymarine DSM250

1-4 DSM250 Digital Sounder Module • Transducer detection. For safety reasons, if the transducer is disconnected and then reconnected while the sounder is powered on, the DSM250 does not detect that the transducer has been re- attached. In this ca...

[Page 15] Raymarine DSM250

Chapter 1: Overview 1-5 Transducer The DSM250 requires a transducer, mounted either thru-hull, in- hull, or on the transom. Transducers can measure water depth, and if so equipped, temper- ature, distance traveled, and/or speed. It is important to po...

[Page 16] Raymarine DSM250

1-6 DSM250 Digital Sounder Module You can customize the sounder by choosing what is displayed and how it is displayed (including language and units). For example, you can set the scroll speed of the bottom graph display, and you can select the ran...

[Page 17] Raymarine DSM250

Chapter 1: Overview 1-7 Operating Modes Depending on the types of display(s) you have connected via hsb 2 , up to four full-screen modes – sonar, chart, radar, and data log are available. You select the operating mode using the DISPLAY key as d...

[Page 18] Raymarine DSM250

1-8 DSM250 Digital Sounder Module Note: Receiving and displaying position data requires that a GPS is connected to your Raymarine system. Figure 1-4: Half-Screen Windows in Sonar Mode Details on selecting windows are given in Chapter 3....

[Page 19] Raymarine DSM250

Chapter 1: Overview 1-9 • Zoom – enlarges all or part of the bottom graph display. You can select x2, x4, or x6 magnification and the zoom area can be auto- matically or manually adjusted. You can select the Zoom or Bottom Lock image to be displ...

[Page 20] Raymarine DSM250

1-10 DSM250 Digital Sounder Module Figure 1-5: Sonar Display Options ZOOMFREQUENCY BTM.LOCK A-SCOPE AUTO GC Z H 0 80 200kHz 50kHz 200kHz 50kHz 200kHz 50kHz SPLIT 0 ZOOMFREQUENCY BTM.LOCK A-SCOPE AUTO GC Z H 0 80 6.8 27.2 27.2 200kHz 50kH...

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Chapter 2: Installation 2-1 Chapter 2: Installation 2.1 Introduction This chapter provides installation instructions for your DSM250. Basic systems, such as that in Figure 2-1 below, are explained. Details for mounting the DSM250 and connecting th...

[Page 22] Raymarine DSM250

2-2 DSM250 Digital Sounder Module Planning the Installation Before you install your system, plan the installation, considering: • Correct transducer for your application. See document number 81196, Transducers for Fishfinders Owner’s Handbook. �...

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Chapter 2: Installation 2-3 This will not damage the equipment, but may cause the loss of some information and may change the operating mode. • Raymarine specified cables are used. Cutting and rejoining these cables can compromise EMC performance...

[Page 24] Raymarine DSM250

2-4 DSM250 Digital Sounder Module 2.2 Unpacking and Inspecting the Components Unpack your system carefully, to prevent damage to the equip- ment. Save the carton and packing, in case you need to return a unit for service. Check that you have all the...

[Page 25] Raymarine DSM250

Chapter 2: Installation 2-5 CAUTION: Do not mount the DSM250 in the engine compartment. When planning the installation, the following should be consid- ered to ensure reliable and trouble free operation: • Access: There must be sufficient space bel...

[Page 26] Raymarine DSM250

2-6 DSM250 Digital Sounder Module • Where a cable passes through an exposed bulkhead or deckhead, a watertight feed-through should be used. • Secure cables in place using tie-wraps or lacing twine. Coil any extra cable and tie it out of the way...

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Chapter 2: Installation 2-7 Figure 2-3: DSM250 Unit Dimensions 9.96 in (252.9 mm) D6168-1 3.46 in (88 mm) 9.51 in (241.6 mm) 10.76 in (273.3 mm) 7.37 in (187.2 mm) Weight: 2.2 lbs (1.0 Kg) Compass Safe Distance: 39 in (1 m) 2.43 in (61.7...

[Page 28] Raymarine DSM250

2-8 DSM250 Digital Sounder Module 2.5 Mounting the Sounder Module The DSM250 can be installed either above or below deck using the supplied hardware. CAUTION: Do not mount the DSM250 in the engine compartment. To allow for proper water drainage and ...

[Page 29] Raymarine DSM250

Chapter 2: Installation 2-9 Figure 2-4: Mounting the DSM250 2.6 System Connections The rear of the display unit provides the following connection sockets: • Transducer connection. • Ground connection. • Power, for 12 V, 24 V, or 3...

[Page 30] Raymarine DSM250

2-10 DSM250 Digital Sounder Module DC Power Connection The DSM250 is intended for use on ships’ DC power systems rated from 10.7 V to 32 V. The power connection to the unit should be made at either the out- put of the battery isolator switch, or a...

[Page 31] Raymarine DSM250

Chapter 2: Installation 2-11 WARNING: If the power connections are accidentally reversed the system will not work. Use a multimeter to ensure that the input power leads are connected for correct polarity. There is no power switch on the DSM250. Th...

[Page 32] Raymarine DSM250

2-12 DSM250 Digital Sounder Module hsb 2 Connection The DSM250 must be connected to an hsb 2 PLUS Radar, Chart- plotter, or Fishfinder display unit to show echo sounder data. The DSM250 will not work with older HSB (non-PLUS) displays. Note: Olde...

[Page 33] Raymarine DSM250

Chapter 2: Installation 2-13 Transducer Connection A 30 ft (10m) cable is supplied with the transducer. The trans- ducer cable may be extended up to a maximum of 60 ft (20 m) using optional extension cables. For details, see document number 81196, ...

[Page 34] Raymarine DSM250

2-14 DSM250 Digital Sounder Module Note: If your system requires both a Y-cable and a transducer exten- sion cable, ensure that you connect the Y-cable to the sounder module and the extension cable to the transducer. The connector pins are shown in ...

[Page 35] Raymarine DSM250

Chapter 2: Installation 2-15 If the transducer cable is accidentally removed while the DSM250 is powered on, remove power from the sounder module, replace the transducer cable, and then return power to the module. As a safety feature, the DSM250 o...

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2-16 DSM250 Digital Sounder Module ...

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Chapter 3: Getting Started 3-1 Chapter 3: Getting Started 3.1 Introduction This chapter provides basic instructions to get you started using the DSM250 Digital Sounder Module. It describes automatically updating the display unit’s software to be ...

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3-2 DSM250 Digital Sounder Module 3.3 Updating Software on the Display Unit Before it can show sonar data received from the DSM250, the dis- play unit must be running a software version that recognizes the sounder module on the hsb 2 network. The ...

[Page 39] Raymarine DSM250

Chapter 3: Getting Started 3-3 However, if your repeater display is a PLUS fishfinder, you must tell the unit to be a repeater. ➤ To set the fishfinder display to be the sonar repeater: 1. Press the MENU key. The Menu soft keys appear. 2. Press t...

[Page 40] Raymarine DSM250

3-4 DSM250 Digital Sounder Module Figure 3-1: Using the DISPLAY Key The selected mode is shown by an icon with a black (mono- chrome display) or red (color LCD) border and the mode is dis- played on the screen. When SONAR mode is show...

[Page 41] Raymarine DSM250

Chapter 3: Getting Started 3-5 Figure 3-2: Typical Sonar Mode Display 3.6 Simulator Mode The DSM250 includes a simulator function that enables you to practice operating in Sonar Mode without data from the trans- ducer. The sounder must ...

[Page 42] Raymarine DSM250

3-6 DSM250 Digital Sounder Module Figure 3-3 demonstrates how to setup the DSM250 for Simulator mode; Chapter 2 gives full installation details. Figure 3-3: Simulator Mode Setup Viewing Simulator Data After you have properly connected ...

[Page 43] Raymarine DSM250

Chapter 4: System Setup 4-1 Chapter 4: System Setup 4.1 Introduction Once you have installed your DSM250 and are familiar with its basic operation (described in Chapter 2 and Chapter 3), you need to set it up so that it displays information accordi...

[Page 44] Raymarine DSM250

4-2 DSM250 Digital Sounder Module ➤ To change settings: 1. Press the MENU key in Sonar mode to display the set up soft keys. 2. Press the soft key for the set up you desire. The requested set up menu is displayed, listing the paramete...

[Page 45] Raymarine DSM250

Chapter 4: System Setup 4-3 4.3 System Set Up Parameters The SYSTEM SET UP option enables you to set up your system con- figuration and personal preferences. The following table lists the System menus and their options, shows the factory default set...

[Page 46] Raymarine DSM250

4-4 DSM250 Digital Sounder Module MENU TIMEOUT PERIOD NO TIMEOUT, 10, 20, or 30 SECONDS NO TIMEOUT DISTANCE UNITS NAUTICAL MILES, STATUTE MILES, KILOMETERS, or KILOYARDS NAUTICAL miles SPEED UNITS KNOTS, MILES PER HOUR, or KM PER HOUR KNOTS DEPTH UN...

[Page 47] Raymarine DSM250

Chapter 4: System Setup 4-5 Data Boxes Press the SELECT BOXES soft key to display the data box sub-menu. This enables you to select up to 6 data boxes that you can display on the sounder. Note: 1. A fixed set of sixteen (nine in the monochrome dis...

[Page 48] Raymarine DSM250

4-6 DSM250 Digital Sounder Module Bearing Mode The mode (magnetic or true) of all the bearing and heading data displayed. This is indicated in the radar status bar after the head- ing value, if displayed. Cursor Reference The mode of the bearing dat...

[Page 49] Raymarine DSM250

Chapter 4: System Setup 4-7 Help When Help is set to ON, a prompt appears when selecting a soft key or menu choice and when using the context-sensitive cursor. The help message is cleared when an action is selected. Soft Keys When the Soft Keys opt...

[Page 50] Raymarine DSM250

4-8 DSM250 Digital Sounder Module This setting does not affect the default soft key labels, which are controlled by the Soft Keys option (see above). Units You can set the units for speed, depth, and temperature. The units you set will be used to d...

[Page 51] Raymarine DSM250

Chapter 4: System Setup 4-9 Manual Mode If you select Manual mode, by pressing either of the MANUAL keys, you can specify the local variation value according to the area in which you are operating. Press the appropriate MANUAL key to adjust the va...

[Page 52] Raymarine DSM250

4-10 DSM250 Digital Sounder Module The factory default for all NMEA sentences is transmission ON. Disable the sentence by selecting the OFF soft key. The following table displays the available NMEA sentences and their meanings. The changes do not ...

[Page 53] Raymarine DSM250

Chapter 4: System Setup 4-11 Note: The DSM250 outputs the same depth value for DBT and DPT, regardless of the Depth Offset value in Sonar Setup. Cursor Echo You can set up an integrated system so that radar and chartplotter displays connected via S...

[Page 54] Raymarine DSM250

4-12 DSM250 Digital Sounder Module GPS SOG/COG Filter The SOG/COG filter averages the velocity vectors to compensate for the oscillating motion of the vessel, giving a clearer indication of the vessel’s course and speed. The filter does not affec...

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Chapter 4: System Setup 4-13 • Radar provides simulated radar picture, with example targets. The picture does not change if you change the range, although the range rings are adjusted (see radar documentation). • Both provides simulated data an...

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4-14 DSM250 Digital Sounder Module Target Depth ID You can select whether the depth is shown for sonar echoes dis- played on the screen. When Target Depth ID is set to ON, the depth is displayed just above each fish echo. When set to OFF, the depth...

[Page 57] Raymarine DSM250

Chapter 4: System Setup 4-15 This is not an issue when showing DSM250 data on a radar or chart display because these units can never be a sonar master. In this case, the DSM250 is automatically set as the master and the display unit as the repeate...

[Page 58] Raymarine DSM250

4-16 DSM250 Digital Sounder Module Speed Calibrate If the transducer is equipped with a speed paddle wheel, the DSM250 calculates the speed of the boat through the water. The speed calibrate option enables you to adjust the displayed speed so that...

[Page 59] Raymarine DSM250

Chapter 4: System Setup 4-17 HIGH cleans up much more interference but can degrade the appearance of actual targets. AUTOMATIC selects the best rejection level for you. The default setting is AUTOMATIC. Sonar Simulator The simulator enables you to ...

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4-18 DSM250 Digital Sounder Module ...

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Chapter 5: Basic Display Controls 5-1 Chapter 5: Basic Display Controls 5.1 Introduction This chapter will help you to become familiar with the functions of the display’s controls in Sonar mode. More detailed informa- tion on operating Sonar displ...

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5-2 DSM250 Digital Sounder Module ➤ To change the lighting and contrast: 1. Press the MULTI key (or the MULTI knob on CRT radar units) to display the soft key controls: The last-used soft key is highlighted in inverse video (white text on a black...

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Chapter 5: Basic Display Controls 5-3 You can also select the color set, for a bold or soft color palette. The brightness of the screen can be adjusted over a wide range, suitable for viewing in daylight (high brightness level) or at night (low br...

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5-4 DSM250 Digital Sounder Module Selecting the Background Color Five colors are available for the sonar display background – black, dark gray, light gray, white, and dark blue. The color you select is used on all the sounder windows (scrolling b...

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Chapter 5: Basic Display Controls 5-5 3. Press the COLOR THRESH soft key. The color threshold soft keys are displayed below color indicator showing the available echo colors. The weakest color is at the bottom of the indicator, the strongest color...

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5-6 DSM250 Digital Sounder Module The controls are summarized in the laminated Quick Reference card that accompanies this handbook. Selecting the Display Mode If the data is available on your system, the following display modes can be selected: •...

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Chapter 5: Basic Display Controls 5-7 Figure 5-1: Selecting the Display Mode Horizontal Half -Screen Window Options Using horizontal half screens, the main operating mode is dis- played in the upper window; you choose what is displayed ...

[Page 68] Raymarine DSM250

5-8 DSM250 Digital Sounder Module • Chart display: If data is available on the display or via the hsb 2 link, it can be displayed. • Radar display: If data is available on the display or via the hsb 2 link, it can be displayed. • Depth/...

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Chapter 5: Basic Display Controls 5-9 Figure 5-2: Horizontal Half-Screen Windows SELECT WINDOWS WINDOWS OFF ON SPLIT HOR VER D6165-1 ZOOMFREQUENCY BTM.LOCK A-SCOPE AUTO GCRZFH 50kHz 0 STEER PORT WAYPOINT 001 XTE WPT BRG WPT RNG TTG 0.28...

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5-10 DSM250 Digital Sounder Module Figure 5-3: Radar Half-Screen Window Vertical Half -Screen Window Options You can also use the DISPLAY key to select a data window that is vertically split with the full-screen Sonar mode display. Ver...

[Page 71] Raymarine DSM250

Chapter 5: Basic Display Controls 5-11 Figure 5-4: Selecting Vertical Half-Screen Windows Note: Receiving and displaying position data requires that a GPS is connected to your Raymarine system. Figure 5-5: Vertical Half-Sc...

[Page 72] Raymarine DSM250

5-12 DSM250 Digital Sounder Module Figure 5-6: Vertical Half-Screen Window C Returning to the Full-Screen Display To return to the full-screen display you can turn windows off, as previously described. To return to full-screen display:...

[Page 73] Raymarine DSM250

Chapter 5: Basic Display Controls 5-13 Alternatively, when you have both sounder and radar displayed in half-screen windows the soft key RDR SNR lets you toggle operat- ing control between the sounder and the radar window. ➤ To change...

[Page 74] Raymarine DSM250

5-14 DSM250 Digital Sounder Module Viewing Data Boxes The cursor data box and a group of up to six data boxes can be displayed if the information is available on your system. You select which data is displayed in the boxes during system set up as ...

[Page 75] Raymarine DSM250

Chapter 5: Basic Display Controls 5-15 The DSM250 defaults to manual scroll adjustment at full speed (100%). Use the trackpad to decrease the scroll speed in 10% increments down to 0% (pause). Unlike automatic adjustment, manual scroll speed is no...

[Page 76] Raymarine DSM250

5-16 DSM250 Digital Sounder Module If, however, you wish to manually adjust the power to suit current conditions, you can select either LO or HI power. LO power (100 W) is normally used in depth ranges less than 8 ft (2.4 m) and HI power (600 or 1...

[Page 77] Raymarine DSM250

Chapter 5: Basic Display Controls 5-17 1 Depths greater than 3000 ft (1000 m) require a high performance transducer ➤ To adjust the range and shift values: 1. Press RANGE, this sets adjustment to manual and the range soft keys are displayed. The ...

[Page 78] Raymarine DSM250

5-18 DSM250 Digital Sounder Module 4. To adjust the shift, press the appropriate SHIFT soft key: use the up soft key to select a shallower shift, use the down soft key to select a deeper shift. The image window is shifted up by the selected amount...

[Page 79] Raymarine DSM250

Chapter 5: Basic Display Controls 5-19 When bottom is found, Hunt mode ceases and the sounder adjusts to the range and frequency appropriate for the new depth. While the DSM250 searches in Hunt mode, a constantly changing ‘stairstep’ pattern i...

[Page 80] Raymarine DSM250

5-20 DSM250 Digital Sounder Module Split Frequency The transducer can operate in both 50 kHz and 200 kHz frequen- cies at the same time. If you choose split frequency operation, the scrolling bottom display is split horizontally; the upper half show...

[Page 81] Raymarine DSM250

Chapter 5: Basic Display Controls 5-21 Range intervals on Bottom Lock are measured up from the bottom (rather than down from the surface). Thus, the bottom is shown as zero and the top number indicates the maximum distance above the bottom being d...

[Page 82] Raymarine DSM250

5-22 DSM250 Digital Sounder Module Figure 5-8: Bottom Lock Display with Split Windows ➤ To reposition the bottom lock image: 1. Use the trackpad to move the cursor to the bottom image until the text B L is displayed near the cursor. 2...

[Page 83] Raymarine DSM250

Chapter 5: Basic Display Controls 5-23 ➤ To display the A-Scope image: 1. Press the A-SCOPE soft key. The display is split vertically, with the A-Scope image in the right hand window and the scrolling bottom image in the left hand window. 2. Pres...

[Page 84] Raymarine DSM250

5-24 DSM250 Digital Sounder Module Figure 5-9: The Three Modes of A-Scope Using Zoom Zoom enlarges all or part of the scrolling bottom display. You can select automatic zoom so the sounder keeps the bottom in the lower half of the disp...

[Page 85] Raymarine DSM250

Chapter 5: Basic Display Controls 5-25 Figure 5-10: Zoom with Split Screen 4. Press the ZOOM AUTO MAN soft key to toggle the setting between AUTO and MAN. The automatic setting adjusts the position of the zoom window so that bottom det...

[Page 86] Raymarine DSM250

5-26 DSM250 Digital Sounder Module ➤ To reposition the zoom window: 1. If you have not already done so, make sure the unit is set to MANUAL zoom. 2. If the cursor is not already visible, press ENTER for the cursor to appear. 3. Use the trackpad t...

[Page 87] Raymarine DSM250

Chapter 5: Basic Display Controls 5-27 Figure 5-11: Repositioning the Zoom Window Selecting Zoom automatically switches OFF Bottom Lock and A- Scope, if either of these images were being displayed. If you have split frequency selected, t...

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5-28 DSM250 Digital Sounder Module ...

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Chapter 6: Sonar Mode Operation 6-1 Chapter 6: Sonar Mode Operation 6.1 Introduction Basic operation, including a description of the different display options, was given in Chapter 5. This chapter explains how to use the display unit to show sonar ...

[Page 90] Raymarine DSM250

6-2 DSM250 Digital Sounder Module The strength of echoes is indicated by different colors (or shades of gray in monochrome displays). You can use this information to determine the size of fish and the bottom structure. Other objects in the water, ...

[Page 91] Raymarine DSM250

Chapter 6: Sonar Mode Operation 6-3 Figure 6-1: Fish Indications Effect of Frequency and Boat Speed The return from a fish has a different appearance depending on the frequency used: 50kHz produces a wide beam, so a fish spot- ted by th...

[Page 92] Raymarine DSM250

6-4 DSM250 Digital Sounder Module Figure 6-2: Sounder Bottom Indications An uneven bottom which is covered with rocks or coral produces a complex display; the bottom image is irregular, with long tails pointing upward. A wreck produces...

[Page 93] Raymarine DSM250

Chapter 6: Sonar Mode Operation 6-5 Using White Line The White Line feature separates echoes from fish near the bot- tom and the bottom itself. When the White Line is switched on, the sounder displays the echoes differently. On color LCDs, the stro...

[Page 94] Raymarine DSM250

6-6 DSM250 Digital Sounder Module You adjust gain for each transducer frequency independently. Press the GAIN ADJUST soft key to highlight the frequency for which you are making adjustments. You may change settings for one frequency while display...

[Page 95] Raymarine DSM250

Chapter 6: Sonar Mode Operation 6-7 The automatic gain modes finds the ideal sensitivity level for you, based on depth and water conditions. Automatic gain modes take advantage the hardware’s advanced DSP technology. As a result, the sounder typ...

[Page 96] Raymarine DSM250

6-8 DSM250 Digital Sounder Module Setting a low value produces wide band for the weakest color, but a small signal band for the other colors; setting a high value gives a wide band for the strongest color, but a small signal band for the other col...

[Page 97] Raymarine DSM250

Chapter 6: Sonar Mode Operation 6-9 • Fish Alarm – If this alarm is ON the unit sounds a buzzer when- ever it finds a fish. Different buzzer tones are used to indicate fish detected by the 50 kHz and 200 kHz frequencies. • Shallow water – Y...

[Page 98] Raymarine DSM250

6-10 DSM250 Digital Sounder Module ➤ To set an alarm: 1. Press the ALARMS key. The alarms soft keys are displayed. 2. For the shallow or deep alarms, press the SHALLOW ALARM or DEEP ALARM soft key then use the up or down soft keys to ...

[Page 99] Raymarine DSM250

Chapter 6: Sonar Mode Operation 6-11 The distance-from-boat continues to update as your boat moves. However, the vertical line does not scroll with the scrolling sonar image. If the display range changes, the VRM adjusts its relative p...

[Page 100] Raymarine DSM250

6-12 DSM250 Digital Sounder Module 2. Use the trackpad to move the cursor and VRM to the desired posi- tion. 3. Press ENTER to drop the VRM, or CLEAR to abandon the opera- tion and return the VRM to its previous position. ➤ To switch the VRM off: P...