FAQ (Frequently Asked Questions) Bellow is a list of Frequently Asked Questions. If you don’t find any FAQs covering your questions, please use the contact form to e-mail the question to RESON. We will try to answer you as soon as possible.
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The SBITS- What are the "SBITS"?
>SBITS are two Control bits that may be set by the user; these two bits are available on the AUX Read more connector. The value is set as the least 2 bits of the [TEST] variable.
SBIT0 pin 6
SBIT1 pin 4
Ground reference is on pin 1.
R2 Command on a NS205 or NS210 - If I make a 'R2' command on my NAVISOUND 205 or 210 then I get a string that is shorter than the R1 string, why?
In the NAVISOUND 205 / 210, the data fields of a second channel are unassigned, in fact they contain Read more internal variables from the bottom detection program. Some of these variables exceed the format available by the R2 command, and consequently the return string is shorter.
C: Although NO HARM will be done to the echosounder, the NAVISOUND 205 / 210 do NOT support the second channel. The R2 and the P2 commands should NOT be used on these echosounders.
The Limit output - What is the "Limit Output"?
The LIMIT output signal is a TTL ( 0-5 V ) signal that indicates the level of the Read more current depth. The signal is intended to close or open a relay in response to the measurement of the current water level (ie. Pump control)
Initially the output is 5V Output is 5V if Depth MAX ALARM Output is 0V if Depth>MAX ALARM Otherwise Output is unchanged NOTE: Both Min and Max MUST be defined for the output to work
The LIMIT Output is available on the AUX connector Pin 7, With Ground reference on pin 1.
Analog output - Can I get an analog depth value out of the echosounder?
The ANALOG output; is a voltage between 0 and 10V, indicating the current measured depth. The dep Read moreth is referenced to the Recorder Range and the Recorder Offset. This signal will drive an analog Voltage instrument, in situations where a simple visual indicator is needed.
ANALOG Output=0V if Depth<recoffs<br /> ANALOG Output=10V if Depth>=RECOFFS+RECRAN Else Output=10*(Depth-RECOFFS)/RECRAN
Note: In order to activate this function, the solder bridge S4 on the Channel PCB must be connected.
The ANALOG voltage is available on the Heave connector pin 4, with ground reference at pin 1. This is done for Channel 1 on all echosounders having V1.4.
Position data (GPS) - The echo sounder has a AUX Port, when a GPS is connected to the echo sounder, can the position then be printed on the thermal paper? Is it printed when there is a mark, or is there any other command for the printing of the position?
The data that comes to the AUX port is not used by the echosounder. The (GPS) data is sent out of Read more the COM port to the attached computer.
To write a text on the paper you use the 'TX' command, this will put the text into the echosounder. Then you send an 'EM3' to set the marker on paper, AND to start writing the text.
for example: TXHERE IS A LINE OF DATA<cr><lf> EM3<cr><lf>
From the software Version 1.2, a function is included so that text lines entering the COM input may be automatically reduced in numbers, and annotated on the paper. From software version 1.4, this is changed, so that it is AUX entering data that may be automatically reduced in numbers, and annotated on the paper.
In Version 1.4, the AUX output will repeatedly transmit a Repeater Data string. This data may be looped back, using a connection between pin 2 and 3 on the AUX connector and then reduced. This will automatically annotate depth as letters on the paper.
TX Cycles - There are 4, 8, 16, 32, 64, 128 and 256 cycles for selection, what are the relevant transmit pulse widths for each cycle?
Wavelength=Soundvelocity / Frequency If you are using a 200 kHz transducer, then the wavelength Read moreis 1500/200000=0.75cm Transmitting 16 pulses will then give a transmit pulse that is 16 x 0.75=12cm long
RX Amplifier – The RX Amplifier mentioned in the manual are: Auto,1,2,3,4,5,6,7,8,9 and 10. What do they mean? Why are there two different curves at the same TVG Range (Curve C and Curve F)?
The receiver gain is controlled by two values. One of the values (The Pre-Amp) is giving a fixed ini Read moretial amplification, whereas the other value (RX Amp) is tied together with the initial dampening control (TVG). The TVG Gain amplification covers approximately 60dB and although it is not evenly spread, the RX-Amp steps can roughly be considered to be of 6dB each. We use the reference numbers 1 - 10 because they do not represent a precise amplification in [dB]. The curves (Label A - F) on the diagram are only showing 6 possible TVC curves. There are in fact 180 different TVC curves. These curves come from the selections. PreAmp 0, 10, 20dB TVC Range 4, 6, 8, 10, 12, 14m RX Amp 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 You get curve 'C' by selecting: PreAmp=20, TVC Range=14, RX Amp=9 You get curve 'F' by selecting: PreAmp=20, TVC Range=14, RX Amp=2 All in all, 3 Preamps, 6 TVG Range and 10 RX Amp settings combine into 3 x 6x 10=180 different curves.
Frequency - for the Navisound210, the manual specifies the frequency as 200kHz. Yet, the transducer is 210kHz. What frequency should be set in the echosounder? Should 200kHz or 210kHz be set? Do they make any difference? (In testing, I have noticed that both settings of 200kHz or 210kHz will work.)
You should select the frequency of the transducer, (210kHz in this case). The receiver of this ec Read morehosounder is capable of receiving any 'High band' frequency from 190 to 220kHz. So, by setting the menu frequency to that of your transducer you get optimum performance from it and as long as the frequency is inside our band, the echosounder can receive it.
The reason it is made like this is because different transducer manufacturers produce different frequencies, such as 200, 208, 210 and 212kHz. The broad receiver band enables the NAVISOUND to use any of these types.
The reason you cannot notice a difference is because most transducers will accept a close frequency, also as a trigger. Even though the deviation will lead to a weaker signal, it is not much. This is only noticeable because it reduces the maximum reach of the echosounder slightly.
For example, it is similar to singing a loud note next to a piano. When you listen to it, you will hear that some of the strings inside the piano are ringing on a frequency nearby.
Command - I have connected the echo sounder to a PC computer's hyper terminal program. The data can be received, but the echo sounder can not receive any command from the computer. For example, "EMx" is input from the keyboard of the computer, but there is no mark appearing on the paper. My question is, can the echo sounder receive the command from a Hyper Terminal Program?
Yes, the echosounder receives commands strictly on a character basis so HyperTerminal should work. < Read morebr>Do note, that the commands are always in upper case, and that each command consists of two command letters and a number of parameters. For the marker this means that 'EM' is the command, and that x is a parameter you should supply.
To set a marker, you should enter: EM1<cr><lf> Where the <cr><lf>are: <carriage return>=Character number 13 <linefeed>=Character number 10
On the Keyboard <cr>=Ctrl key + M (pressed at same time) On the Keyboard <lf>=Ctrl key + J (pressed at same time)
Using paper from other sources - I have changed to a new type of paper and the paper recording is not as clear (Black/White) as it used to be.
The thermal printing paper delivered from RESON is high grade, steep slope paper. This means that th Read moree gradient between white and black is very steep. Therefore, the NAVISOUND is printing in a digital (On/Off) way, this paper produces crisp, clear images.
Other sources of paper generally have a slow gradient, resulting in an image that tends to have varying shades of grey with no black.
Beam angles - Is it true that with a 6 degree transducer we don't cover a full 6 degrees because the return at -3dB is stronger than the side lobe and the signal at -3dB will come before the side signal?
The matter is not a trivial one, however your friend is partially correct providing the bottom is fl Read moreat, with slight protrusions, because the central beam indeed is a lot stronger this will give rise to immediate detection.
The beam angle comes from the more complex signal flow in the water also from the way the echosounder makes transmissions and detects returns.
A 6 degree transducer has a beamwidth of 6 degree at -3dB. This however does NOT imply that detection seizes outside the angle, or that everything inside it, is actually detected.
As the echosounder is sometimes operating on a gain regulated basis, it will adjust the amplification to match a certain received signal strength. However, an object 'A' will reflect a signal earlier than the main lobe and even as this is received at lower signal strength, it will give rise to an echo.
If the echo is strong enough and long enough, it will give rise to an apparent object at 'B' with a depth, matching the slant range to the object at 'C'.
So effectively, you may experience an opening angle of more than 6 deg. In the case of when you approach a steep slope or object, the side lobes WILL hit the nearest object first, giving rise to early echoes. These are normally small and don't match the detection criteria of size and length, but IF they do, they will give apparent echoes.
If your reflection is like steel, much signal is reflected downwards, NOT giving a strong Echo. Highly irregular objects and stones will signal more and reflect back to the transducer, giving rise to detection.
Initial delay - The 200kHz transducer specifications do not recommend any delay. What is your delay?
We recommend a delay of 3cm for 200kHz and 7cm for 33kHz transducers.
It is possible to calc Read moreulate a correct Initial delay during Bar check or by measuring on a hard known bottom (concrete / metal) when the depth and the sound velocity is known for the full water column, it is important that the Transducer under testing has no movements.
Heave compensation - Which information is corrected for heave?
The Correction for wave movement is implemented, on user selection, for the values of: COM Data Read moreoutput, Depth Display, Graphic Digitline and Graphic Heaveline. These three options are set individually in the “Recorder” and “Communication” menu.
Note that: the Timegate lines are NOT heave compensated, because the bottom detector algorithm refers an uncorrected depth data. Therefore, use large Timegate when large waves are present at deep ranges.
Liability- Who is responsible for errors?
We at RESON do our best to ensure the best possible functioning of our equipment. RESON does state i Read moren the liability clause that we are not responsible for direct or indirect loss of profit, or any other incidental or consequential damages in delivering the equipment.
Delayed reaction on Paper Offset change - When I change the Paper Offset and the sounder rate is slower than the recorder printer rate, it looks as if the trace is delayed. Why does the digital line change immediately?
The digital line, which is recomputed every time the paper moves one pixel ahead, will immediately r Read moreeflect the new paper selections.
The graphical trace is tied to the physical sound pulse traveling in the water, and will have to wait until the start of the next free sounding before it reflects any new settings. In large Ranges (Slow sounding rates), this will look as if the trace is delayed, while it is actually finishing a sounding sequence.
NOTE: The measured data is not influenced by the change in paper offset.
Activate PC communication - My NAVISOUND is set to output data on request, is there any way that I can start the continuous data output remote from a PC, without operating the menu system?
First send a PC command to get the current settings, then change the output mode to "First command" Read moreand finally send the PC again to start the output. ie. Send Answer PC PC3801000380103801 PC3801200380103801 PC3801200380103801 PC PC3801200380103801 DA............ 2 Indicates “First command”
When I am loading settings from FACTORY, GET1, GET2 or GET3 the data gets fine into all the registers, but the Baudrate, Data bit, and Parity of the COM and AUX channels don't change. Why?
When loading settings, we may be in the middle of an active survey. Loading wrong data may lea Read mored to loss of depth information which is unfortunate, but in some way acceptable (given the action of loading settings). BUT in the registers there may be COM settings that differ from currently used values. Accepting these blindly, may lead to an output of strange characters (Wrong Baudrates/Bits) which may in some cases be fatal to the Survey computer, in the middle of its operation. Therefore, the COM and AUX settings are loaded, but not issued to the COM and AUX ports.
There are 5 levels of gray on the NAVISOUND 200 paper recorder, but the recorder can only print Black and white, so how are the 5 levels obtained?
When the recorder was developed, we considered many ways to produce grey levels, however when it com Read morees to echo signals reflected from the seafloor, it became clear that areas of grey appear on the paper. Therefore a pixel sharing method could be used, so that if a group of pixels agree on a level of grey, then only some of these pixels are actually switched on. Looking at the 16 possible combinations of 4 pixels, we find that there are 5 pattern groups. Each pattern group produces a distinct level of grey.
When I do a bar check, it will sometimes lock on the bottom instead of the bar, why?. How does it work?
When the Bar Check function is selected, then all echoes are evaluated with reference to the entered Read more Bar depth. However in some cases your bar is emitting a rather faint echo, whereas a strong bottom echo is present, this may lead to a situation where the echosounder uses the strong bottom echo instead of the weak bar. Turn down your TX power, and switch off any TVG action, this may help in regaining an echo from the bar.
What is the minimum depth that I can survey with a NAVISOUND 200/400 echosounder?
The minimum depth specified for the NAVISOUND echosounders is 50 cm. Below this depth you must adju Read morest the echosounder carefully, (an adjustment that not all users can do with comfort). However 20 cm has been surveyed, using 200 kHz, 8 TX pulses, 5m Range and 2W TX Power. From version 1.5, the shallow depth measuring is improved in the way that the echo approval length is as follows. Variable approval length according to selected no. of TX cycles except from following: Half approval. IF we are preforming a Bar Check with half approval we will use 5m. Range and Receiver Amplifier=0 or 1 So one should fine tune, using TX Cycles=8, TX Power=2W Then the approval is decreased to 1/2 of its normal value, and 20 cm is possible.
How can it be that I reach a maximum of 80m using my NAVISOUND 210 and the 200 kHz transducer?
The NAVISOUND 210 is a single channel echosounder, supporting operation on one of two standard frequ Read moreencies ( 200 - 210 kHz and 30 - 33 kHz ) (Other frequencies are available on order) The operational range of the echosounder is 0.5 - 600 meters When doing survey, the actual range is mainly depending on the frequency. So the echosounder itself will support ranges up to 600 meters, but ONLY IF the signal that is returned from the sea bottom is strong enough. For any echosounder, the returned echo strength depends on a number of factors. The three most important are: 1) Sound level dampening in water The dampening is much larger for high frequencies than it is for lower frequencies. This means that a 200 kHz signal will travel a shorter distance than a 33 kHz signal. 2) Material in the water If the water is filled with material like sand, mud or particles, then this will also dampen the echo signal.
The 200 kHz is mostly used in shallow water areas like harbor, lake, river survey. Whereas ocean surveys and continental shelf surveys are mostly done using lower frequencies around 33 kHz (Or in special cases using 15 kHz)
What are the best settings for a normal survey below 100 m, using both 200 and 33 kHz.
The standard settings found by loading Factory settings are quite good in this situation, so when us Read moreing for example a TC2122 dual frequency transducer, you connect the 200 kHz as channel 1 and 33 kHz as channel 2. The Factory settings are sufficient to reach 20 to 30m. on the 200 kHz channel, so to go deeper we change some of the parameters. In the 'Lillebelt* of Denmark, we used these values: (Note that we changed TX Power and TX Cycles from the Factory values) to do our Range test. The area has a maximum depth at about 80m, and strong currents probably expose harder layers of the bottom material. With this setting we achieve a maximum depth of 84m
What is the difference when TVG mode is activated or not? And what is its relation to RX-Amplifier? What function is Initial Lockout for?
TVG is a shallow water function. It is so, that in shallow water (<14m) there are some types of w Read moreater areas (like rivers, and harbors) where the reflections from the upper water layers gets too strong, even when you turn down the power to a small value.
By setting on the TVG, you introduce a function of initial dampening, so that the surface is dampened by the selected factor (i.e. -20dB) and this dampening is then progressively eased off during the first range of meters (i.e. 6m) Such function will then allow you to perform measurements more accurately in difficult near-shore areas. Another function of the TVG is to get the same echo amplitude surveying on different depth (0.5 to 20m).
The RX-Amplifier sets the Gain in the receiver circuit. Set it low in shallow waters, or if you get too much noise, or if your paper gets written very dark. Set it high when measuring in deeper waters.
Initial Lockout, is an echo digitizing lockout function. To avoid the echosounder from tracking it’s own transmission pulse or noise in the top area of the water column the Initial Lockout value have to be set longer than this noise / transmission pulse. To find out the needed length, start the recorder and check how long the black area is in meter from the start of the transmission pulse to where the paper gets white again. If the number of TX cycles is increased it is also necessary to increase the length of the Initial Lockout.
Can we do bar check only in shallow water? Soundvelocity will vary with respect to the water temperature, salinity and depth. How can I get the proper value in deep water? Can I use the same value according to bar check procedure?
Bar check, through history, has been a function, only used in the closest few meters. The reason Read morefor this is that it gets progressively more difficult to control a reflection plate or bar as the distance gets larger, and at depths exceeding 10m it is virtually impossible to perform bar checks. You should also note that when making barchecks at different depths (i.e. 2, 4, 6 m) the measured soundvelocity is a sum of velocities, so the 2m check gives one value, the 4m check gives a value that hold both the found 2m value and a value from the 2 - 4 m distance. 6m is a sum of the 0-2 + 2-4 and the 4-6m results. etc. You must also remember that in most areas the major variation in soundvelocity is in the top 15 m of the water column. Hereafter one may (to some extend) consider it to be fixed (unless of course there are undersea rivers, or thermocline layers in your area)
Most devices now have the ability to set a gate around the bottom lock. This number could be adjusted (4 feet, 6 feet, ect.) This would then only take data that was above or below the bottom by that number. I did not see a setting to adjust the gate width, only a blanking number. Is this feature on the unit or am I overlooking something? Could you explain how the bottom lock feature tracks the bottom and ignores fish and such? (If there is no gating)
There is three different approving of the bottom detection.
1) The bottom echo has to have a Read morecertain length to be approved as the bottom. 2) The echo amplitude has to be big enough to be approved. 3) And the depth has to be inside the Timegate window. The Timegate window is set in the "Technical Menu" as a % of the actual sounder range. The options are 2 - 4 - 8 - 20 % of range.
ie. 20m range (I use meter here) and 4% timegate gives a window of +/- 80cm from sounding to sounding. Depth values falling inside this moving window are deemed OK and a quality assignment is increased. If the following depth jumps outside the window, then its quality is rapidly decreasing, the depth is however still send out of the echosounder, because it is important NOT to loose values and especially those dangerous shallow spikes that might be cliffs or wrecks. The "Initial Lockout" is the minimum detectable distance from the surface and should be set just a little longer than the received transmission pulse seen on the paper.
ie. Set the recorder paper range to 5m and observe the black trace on the top of the paper, this TX Pulse might be 50 centimeter so you can set the "Initial Lockout" to 60cm. If "Initial Lockout" is set too small then there is a risk that the echo will lock to its own transmitter pulse.
Every time I switch on my NS215 it will be in split graphics "1/2" and Multiplexing mode. Even if I change to record Channel 1, and use it for an hour. It still reverts to the "1/2" mode when I switch it off and back on again.
The NS215/NS415 have loaded factory settings which default to Multiplexing mode and recording "1/2". Read more When you change your parameters and leave the echosounder on for more then 20 seconds, your selections will be saved automatically, Except for these two. Set your selections and save it once manually, after that it will automatically remember your selections including the two items. That is until you load factory settings the next time.
I have changed the fuse in my NS400, and wondered, is there an internal fuse in the echosounder?
Yes, the 110/220 V AC module has an internal security fuse. It is a 2 AT 250 VAC type. It can be Read moreaccessed by disconnecting the unit from the mains. By unscrewing the 4 screws (Hexagon type) that hold the rear cover and by removing the cover will reveal the fuse in a small cable cartridge.
Please clarify on 200Khz and 33Khz multiplexing operation for the NAVISOUND 215. In other words, does the single receiver board simultaneously receive both the beams ? Is there any time delay between two beams in multiplexing operation ?
In the multiplexed mode the operating frequency is alternating between two values. typically 200 kHz Read more and 33 kHz. This means that sounding #1 is 33 kHz, sounding #2 is 200 kHz, sounding #3 is 33 kHz, and so on. The echo sounder will send both depth values out to the computer at the same time. The first one will have a short delay, which typically is negligible in shallow waters. Another item to have in mind is the opening angle of the transducers. Typically the 200 kHz is 9 deg, and the 33 kHz is 20 deg. This means that consecutive footprints on the seabed are overlapping, even when the echo sounder is multiplexing. For simultaneously dual channel operation, as in the NAVISOUND 420, both frequencies are transmitted and received at the same time. For this operation the echo sounder has separate transmit/receive circuits for 200 kHz and separate transmit/receive circuits for 33 kHz. There are no time delays between the 2 channels when operating in simultaneously mode. Note that the simultaneously operation is possible even when using the TC 2122 transducer, as the transducer internally is holding separate elements for 200 kHz as well as for 33 kHz.
I would like to make annotated markers, but what options do I have in the NAVISOUND 200/400 family?
Here is a description of the functions of the markers 'AS THEY ARE' Version 1.1 Print Settings: Y Read morees/No Version 1.2 Print Automatic: None,Settings,Mark No.,Com/1,/5,/10,/20,/50,/100,/200 Version 1.3.2 Print Automatic: None,Settings,Mark No.,Com/1,/5,/10,/20,/50,/100,/200 Version 1.3.3 Print Automatic: None,Settings,Mark No.,Com/1,/5,/10,/20,/50,/100,/200 Version 1.4.0 Print Automatic: None,Settings,Mark No.,Com/1,/5,/10,/20,/50,/100,/200 Version 1.4.1 Print Automatic: None,Settings,Mark No.,Com/1,/5,/10,/20,/50,/100,/200 Version 1.5.0 Print Automatic: None,Settings,Mark No.,Com/1,/5,/10,/20,/50,/100,/200 Version 1.5.1 Print Automatic: None,Settings,Mark No.,Mark Text,Aux/1,/5,/10,/20,/50,/100 As you may see, all versions from V1.2 to 1.5.0 were capable of automatic annotation of a string, arriving on the Com port.. From version 1.5.1 it is possible to select either automatic annotation of the Aux string or manual annotation of 'Mark Text' (Using the Aux port allow the function to coexist with the computer connection on the Com port) The 'Mark Text' function will annotate the current depth followed by the latest string data received on the Aux port. A press on the marker button will produce an Un-Annotated marker line when we have selected the automatic string annotation (i.e. Aux/5). It is NOT possible to have the marker annotate depth and string data at the same time as we have selected automatic annotation of an incoming string.
How can I use the AUX port to connect my GPS to my laptop which only has 1 COM port? Is it possible to see the GPS data arriving at the echosounder before it comes to the computer?
The AUX port is designed to be a port expander for small laptop PC systems. Connect your GPS to t Read morehe echosounder AUX connector, BUT do observe that the AUX connector has a different polarity (female) and that it holds additional signals than just RS232. So you will have to make a small interconnect cable.
Now set the menu (Manual section 4.15.4) so the Baudrate, Bits, Parity and Stopbits match that of your GPS. You may now see the incoming GPS data string, by selecting the recorder annotation (Manual section 4.12.1) to be Print Automatic AUX/1 and then switch the recorder on. Select a high recorder speed to see all the GPS data strings. Now, connect your echosounder to the Laptop PC in the usual way, and start your NAVISOFT Survey program. In the menu, Sensors / Echosounder/ go to the last line, and select: Loop Through Pos [x]
Depth and position should now be available to the survey program.
For a typical survey in shallow water, what are the main parameter settings to make sure that it will work? We have a sandy bottom, no more than 15-20m. (Factory settings works from 10 to app. 25m)
Using the NAVISOUND at 20m, I would normally start by using a TX power of 20W, Receiver amplifier at Read more 7, and TX cycles of 16. Watching the paper record, you can then see if it is adequate. If not so then increase power or cycles. Normally I use it with TVC off, but if you experience surface noise then switch TVC on.
Is there a rule of thumb when it comes to the ping rates, or is there a general equation to use to determine ping rate at specific depths. Will this change with frequency? Is the ping rate depending on the number of cycles selected in the sounder at that time?
The ping rate (PRF) is determined by three parts. 1. The internal setup time in the echosounder ( Read moreAbout 0.0092 sec) 2. The travel time of the sound pulse (At the selected range) 3. The fact that we use over range to allow the user some levy in selecting his range (Over range is about 1.5 * selected range) The time for one sounding is (2 * 1.5 * Range / Soundvelocity )+ Set uptime It is multiplied by 2 because it is a single way and the sound needs to go both down and up. For reasons of internal setup, the rate has been limited to a maximum of 20 soundings/sec. So assuming a soundvelocity = 1500m/s
Range 5m => 20 Soundings/sec Range 10m => 20 Soundings/sec Range 20m => 19 Soundings/sec Range 50m => 8.9 Soundings/sec Range 100m => 4.8 Soundings/sec Range 200m => 2.4 Soundings/sec Range 400m => 1.2 Soundings/sec etc Remember that the range of the NaviSound are set in steps, for example you cannot select a 12m step. The transmit frequency (30 kHz or 200 kHz) has NO influence on the sounding rate. The number of TX cycles are within the sounding itself, and do not influence the ping rate.
What happens when we use the NaviSound in Feet mode?
The NaviSound family of echosounders are counting depth at the rate of 76800hz (Corresponding to 1 c Read moreentimeter at 1536 m/s) All measurements are then collected at this rate, and afterwards converted to the output scale selected, it be metric or Feet's.
So the measurement result is given as accurate as possible. When entering values to the system some values are selecting counters using this clock rate, therefore all entries are converted from the given centimeter or feet numbers, to a corresponding number of ticks. as we are using a metric related frequency, the metric values appear nice in the display. But as the Inch/centimeter relationship is not a whole number (But rather some 2.54 cm/in) we will experience some rounding. This is the reason for some menus to step. 3,7,10,13 ft (1,2,3,4 m) instead of 3,6,9,12 feet. In our echosounder we try to be as correct as possible, therefore, when a user enters a numeric feet value, we instantly convert it to the corresponding ticks, and then back to the corresponding value, in the selected unit. Entering Draft for example is done in meters as:
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 These values correspond to the feet values (Using 1 foot=0.3048m, 1m=3.2808feet) 0.00 0,032808 0,065616 0,098424 0,131232 0,16404 0,196848 0,229656 0,262464 0,295272 0,32808 As our display shows the entered value as feet with 2 decimals, the truncated display values become: 0.00 0,03 0,06 0,09 0,13 0,16 0,19 0,22 0,26 0,29 0,32
As you may see from this, the values we use are actually given as 1/100 of a foot which is about 3 mm, this is finer resolution than possible for the echosounder, therefore a draft selection of 0.01 0.02 0.04 etc is not possible using feet. This is also the reason we truncate the display instead of rounding.
Another thing is selection of meter vs. feet. this is done in two places. One place is in the data output, governing both digital output as well as the displayed values. The other place is the selection of, what to bring on paper.
The two way selection allow a metric survey group to make their measurements in the scale that they are accustomed to, and still they may produce a paper record to a client that insist on feet presentation. (or visa versa) I do agree that this may seem ark ward to a feet user, but - independent of the scaling, some conversion HAS to be done, from meters to electronic clocks, and from feet to electronic clocks.
We have decided to use the same way of presentation for metric users as for feet users, and in doing that, the different size of the smallest unit will show up in one way or the other.
Are there alternative methods to calibrate an echosounder?
Yes: Here is an alternative to the build in BAR Check method. This procedure is developed and use Read mored by Army Corps of Engineers - USA.
1. Set the BAR to 10 Feet. 2. Adjust the Draft until it is showing correct value. 3. Set the BAR to 40 Feet. 4. Adjust the Soundvelocity until it shows correct value. 5. Raise the BAR to 30 feet, then 20feet and finally 10feet and check that it is still right.
The basic formula for the Barcheck soundvelocity is: Measured_Soundvelocity=Real_Soundvelocity * Selected_Depth / Real_Depth One thing to note about Barcheck is, that "Accuracy is important", and we are also urging to caution. A BAR check is for "Checking" the system, not for calibration. Even the slightest error between real bar depth, and informed depth, or in detection threshold, or change in transmit power or. or... will influence the measurement.
What is the difference between the echosounder versions 1.4 and 1.5?
Here is the new stuff in V1.5: ======================================== • In BARCHECK mode T Read moreimegate is locked around the bar • In BARCHECK mode Blank result if depth falls outside the Timegate • Echo approval time is processed, depending on settings BarCheck mode selected: = Approval / 2 If Range=5m and RX=0 or 1: = Approval / 2 • Corrects an error in GT command. • Disable display channel 2 when operating NS200 in single mode • New default values Initial lockout: Ch1=60cm, Ch2=120cm Start NS215 and 415 in MUX mode NS215 and 415 Recorder mode is 1/2 Force Communication to NMEA in a NS205 • Use high paper speed when printing settings • Values and steps of Feet mode is changed • Revised the AUX function Added a Mark function to print Depth with AUX data Added a <cr> after stripping the AUX input Rescheduled AUX repeater priority to be concurrent with Com port Corrected a buffer overflow error in AUX input • Corrected an error that always recorded Channel 1 if TimeGate lines were activated • Retro Implement LED blinking in V1.5.2++ to make it compatible with the new gray display foils
Do you have a general rule for frequencies and min/max ranges with the standard 300W NS 200/400 sounders?
The actual range may be less due to bottom condition or bottom slopes. It also depend on the boat Read more type, where the transducer is mounted, the transducer opening angle, the sea state, and the settings used in the echosounder.
I am trying to connect my GPS to the NAVISOUND echosounder. When I read GPS on my PC then it works fine, but I don’t get any data when it is connected to the NAVISOUND?
Please check that your connections are correct. The COM output has: Ground on pin 5 connect to PC Read more pin 5 RXdata on pin 2 connect to PC pin 3 TXdata on pin 3 connect to PC pin 2 The AUX input has: Ground on pin 5 connect to GPS Ground RXdata on pin 2 connect to GPS TX data (Probably pin 2) TXdata on pin 3 (This is a constant output of echosounder repeater data From Ver. 1.7 it is possible to deactivate the Repeater output in the “Communication” menu to avoid conflict in the GPS unit. Note that the COM is a 9 pin FEMALE and the AUX is a 9 pin MALE connector, If you use a sex-changer bought in a shop, they often twist the pins 2 and 3.
How do I get the best result using Auto Gain (200 Khz)?
You should pick an area with average depth, set the TX cycles to 32 and set the Gain (Amplification) Read more to a mid value i.e. value 6 - select a power setting between 20w and 300W giving a nice stable echo trace on the recorder paper and then select Auto gain instead of gain 6 and start the survey. With this settings it should be possible to sail into shallow or deeper water without adjusting the sounder further. If the bottom track disappear due to air bubbles, turbulence or ship propeller water then it may happen that you have to use manual gain setting shortly and then shift back to Auto Gain. In case of muddy bottom you should increase the TX cycles to 64 or 128. If TX cycles is increased the Initial lockout should also be increased from default 0.8m to app. 2.0m
