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HydroScat-2 User`s Manual - Hobi Instrument Services

1. rese Eros to oec otov enero 39 E 39 323 IMBRE MM SS cu rte 39 6324 TIMERES 40 8 4 TIME RESOLUTION LOW 1 SECOND SPECIAL PURPOSE COMMANDS eere 40 6 4 1 AGAIN channel QU O esses eee eee een hne reete nee 40 0 42 5 ttc rettet RO EUER HEURE Ce aa 40 843 GAIN Chameleon Re RH 40 844 GGkaddr ss Baudrdte i cate di tente ictus 41 42 DATA PROCESSING REFERENCE eesssesssooeesecoesseecesseeessoeessoceesseceecoecssooesssooessseeesseesssoesssooeesseee 45 9 1 RAWDATA FORMATS o 45 925 PACKET FORMAT tr A sida 45 921 Example D Packet ss id A te teo reat eb ia 45 922 ED SP AGREES WUC TUTE aue A 45 QD 3 PACK CL FLAG A e e d e eee eoe 46 9214 EE 46 TD 46 920 SNOM IV 46 02 een 47 47 iv 92 907 e A dst deo 47 DELO EON EE M TIRE 47 0 Lb CHECKSUM ta
2. T a eh SCP Dat Mn 48 212 Ln A Be 48 9 3 T PACKET FORMAT FIRMWARE 1 60 AND LATER 48 9 3 12 Example T Dackel e ERE EE ER TIO s e ERE 48 0 3 2 Terre ers esee n ec eoe ik Po B eie EE Ede es 48 94 SH PACKET FORMAT E EE EE E E 49 941 Example Packets ad ada 49 022 ticas avala 50 943 SEON Ref t CERE VR ee ae he 50 Back qe EE RENA 50 945 VsupB 50 Do ce ose ie 50 027 e 50 0486 LCFIMIN ALON 50 9 5 CALCULE TINGBAND Ba TD 51 9 6 SIGMA CORRECTION ada EE 52 97 CALEEEFORMAT 3 nee WR P REB ORE DERI RI ID ee 55 10 ANTI FOULING SHUTTER OPTION cccccccscscssscscsecccsceccsscececscececececesesscecesscecesscesesesescscees 57 10 T DESCRIPTION ete ettet Reo ni tei A E ht ase A OS 57 10 2 SWEARING A roads a 57 10 35 OPERATION sn em et o etes head electives 58 104 OPERATION TIME rends ere ne A EEE 58 10 5 SHUTTER SPECIFIC COMMANDS ccccccccecessesssceeececeesesseececceseseaeceecceceesaaeeeseesesensaueeeeceesensessseeeeeens 58 10 5 1 SHUTTER auto time Firmware 1 807 38 10 32 SOREN MAA i
3. FE Sigot2 signed 4 0445 signed 4 560 Rerom signed Back signed 2 FF Soons signed 4 Res signed HH 4 4007 Rerons signed Backs sgmd HH 2 Sigom signed 0608 AIAI AINI Re signed ROTE signed HHH 4 fie HH 2 saors signed os signed Rerons signed HHHH osco A A AY nj Backs signed HH 2 FF Sigo aoa Reis signed HHHH 4 5488 signed HHHH Backer ene Re figned af oo signed Back HH 2 0 Sigo signed HHHH 0000 ABD PAIN A BR RID AJN 49 Back signed Hi 2 99 u set to zero by HydroScat 2 9 4 2 Time Same as D packet time 9 4 3 SigOff Ref RefOff These three values one set for each of the optical channels are incorporated into the calculation of Snorm and are not needed for normal post processing 9 4 4 Back This signed integer indicates the amount of background radiance incident on the detectors Its value is normally a small positive number for the HydroScat 2 A large value indicates bright background light presumably sunlight which may contribute to noise in the backscattering data
4. Burst cycle 10 minutes Total duration 0 hours not in effect NOTE Changes you make to the log parameters remain in effect only as long as the sensor is powered unless you make them permanent with the STORELOG command section 8 3 21 8 3 13 OPEN time Opens the optional anti fouling shutter See section 10 5 2 8 3 14 RAM Displays information about the log memory in the following form 339960 1017856 bytes 33 used in log RAM 37 10059 29976 packets logged First packet logged 05 01 97 13 40 42 Last packet logged 05 01 97 14 28 02 The first line shows how many bytes are used and the total memory the system The second line shows how many packets samples are stored and the approximately maximum number of packets that can be stored If the memory is empty the last two lines are omitted The accuracy of the dates and times presented depends on the HydroScat s real time clock being set accurately See DATE 8 3 7 and TIME 8 3 23 8 3 15 SHUTTER auto time Firmware 1 80 SHUTTER 3enable auto time direction Firmware 1 84 and later Controls parameters for the optional anti fouling shutter section 10 5 1 8 3 16 SLEEP secs The SLEEP command causes the HydroScat to immediately cease any data collection and go into a low power sleeping state this state the current consumption is reduced to a level similar to the battery s self discharge rate The secs argument if included s
5. D346A023C055613CC160600000000000000000000555000000648870071 lt CR gt lt LF gt 9 2 2 D Packet Structure Parameter Type ASCII ASCII Bytes Example Packet Flag PacetiD ha D Time signed HHHHHHHH 8 346 023 Snomi signed HHHH 0596 Snom2 signed Ha 13 Snom3 signed a 4 1606 5 signed HHHH 4 0000 Snorm5 signed HHHH 4 0000 Snorme signed HHHH 4 0000 Snorm7 signed HHHH 4 0000 Snorms signed 4 0000 AR RY BR RPA Gain Statust 5 Gain Status2 5 Gain Status3 5 Gain Status4 0 Gain Status5 0 Gain Status6 nibble H 1 0 45 Gain Status7 Gain Status8 DepthRaw TempRaw Error nibble nibble H 1 unsigned HH paa Checksum Terminator lt CR gt lt LF gt 2 Zu set to zero by TOTAL HydroScat 2 9 2 3 Packet Flag Each data packet begins with an asterisk character Other transmissions for example replies to commands may begin with other characters 9 2 4 Packet ID The packet described here is identified by a D in this position HydroScats may produce other packets of various lengths with other identifiers 9 2 5 Time TIME is in seconds If the HydroScat s real time clock has been set accurately See section 5 6 a time of zero represents Midnight January 1 1970 The time shown in the example above
6. 19 Close the open data file by selecting Close from the File menu or clicking on the Xl button If desired save the file when prompted Downloading Data From the HydroScat 20 Select Get Data From Instrument from the HydroScat menu 21 After several seconds a directory of casts in memory will appear The last cast listed should be the one you just recorded If that cast is not already highlighted click on it to highlight it or click the Select All button 22 Click the Browse button to select a directory in which to save downloaded data files In the resulting dialog box select a directory and click the Select button 23 If it is not already checked check the Create calibrated data dat files option 24 Click the Download button to begin transferring data casts Disconnecting 25 After you are finished communicating with the HydroScat select Disconnect from the HydroScat menu When asked Put HydroScat to sleep before disconnecting click Yes 26 Unplug the battery charger from AC power 27 Unplug the cable from the HydroScat s underwater connector Switch Activated Logging see also section 5 9 28 To start a cast when the HydroScat is asleep and disconnected from the computer move the magnetic switch to the on position see Figure 3 on page 4 10 29 To end a cast return magnetic switch to the off position 11 4 HYDROSOFT SOFTWARE HydroSoft is HOBI Labs Windows based software for commun
7. 346A023C corresponds to November 12 1997 at 19 23 40 When power is first applied to the HydroScat the time may proceed from a random value It is not necessary to set the time if absolute time data are not required 9 2 6 Snorm There is one 16 bit Snorm value for each of the 3 optical data channels Note that some channels may be disabled as indicated by their Gain Status values in which case the Snorm value is meaningless It is calculated by the HydroScat from S R Sig SigOff SigDark norm nom Ref RefOff where Sig and Ref are the raw signal and LED reference measurements SigOff and RefOff are the signal and reference measured during the time when LED is off Rnom and SigDark are parameters from the HydroScat s calibration record Snorm is a 16 bit signed integer Snorm is used to calculate backscattering as shown in section 9 5 46 9 2 7 Gain Status There is 4 bit gain status value for each of the optical data channels The three LSB s comprise a gain setting and MSB indicates status A gain setting of zero indicates that the channel is disabled and its data should be ignored Gains of 1 to 5 are used to select one of five coefficients to be applied to Snorm Gains 6 and 7 are undefined The status bit is zero under normal conditions The status bit for a channel may be set to 1 if the HydroScat detects a condition that may affect the quality of the data on that channel However a status
8. 15 seconds Burst cycle 10 minutes Total duration 0 hours not in effect Sampling and Logging Parameters Log Period 1 seconds Start delay 60 seconds Sleep when memory full 1 Start on power up 0 8 3 2 CHANNELS Lists the wavelengths and functions of the 3 channels of a HydroScat 2 in the order in which the HydroScat produces them Reply 1 bb442 12 bb671 3 1671 excitation bb442 8 3 3 CLEARRAM Erases the contents of the log memory Before proceeding displays the memory status the same information as displayed by the ram command and asks for confirmation Reply 339960 1017856 bytes 33 used in log RAM 10059 29976 packets logged First packet logged 05 01 97 13 40 42 Last packet logged 05 01 97 14 28 02 34 ERASE ALL DATA IN RAM Y N N 6699 Press to clear the memory or any other key to abort 8 3 4 CLEARLOG Identical to CLEARRAM 8 3 5 CLOSE time Closes the optional anti fouling shutter See section 10 5 3 8 3 6 D Transmits a D packet of hexadecimal data See section 9 2 for a description of the format 8 3 7 DATE mm dd yyyy hh mm ss Sets the real time clock to the given date and time if provided If no date is given simply reports the current setting The year may be entered either as two or four digits If only two digits are entered years from 00 to 43 will be assumed to be in the 21 century The real time clock is reset
9. a reference temperature for correcting temperature related drift should such corrections be needed 41 Depth offset and depth coefficient are used to translate raw depth data to units of meters These are not used within the HydroScat firmware but are stored there for reference The maximum depth ID model S N and Config fields can only be set with the ID command and are described under ID The firmware version shows not only the sequential version number but which memory configuration it is compiled for This should match the RAM size displayed on the next line Neither of these parameters is editable but is determined within the compiled firmware The calibration and configuration data that are unique to each HydroScat 2 are stored in nonvolatile memory in a format that has changed as more information was added in successive firmware versions The configuration version number identifies the format in which the current information was stored Finally the cal time shows the date and time at which the configuration and calibration data were last altered This is updated automatically and cannot be edited The same parameter is displayed in raw form by the ID command 8 4 5 X X 1s used extensively during testing and troubleshooting since it displays a comprehensive report of the HydroScat 2 s most recent raw data as follows Raw data are also discussed in section 9 1 time 2856 error 2 samples 733 on 11 off bb440 46
10. as zero when a channel is disabled 8 4 4 GCF address Baudrate GCF stands for global configuration This command displays and sets certain parameters that pertain to the HydroScat 2 as a whole Note that not all the parameters displayed can be set with this command Reply Global Configuration Address Baud Rate 9600 Data prefix Info prefix Error prefix Cal Temp 0 000000 Depth Offset 14 1 Depth Coefficient 0 0089 Maximum Depth 200 m ID Institution Model HS2 S N HS97074 Config W1BOR112P2 Firmware 1 10 256K RAM size 256K Config Version 2 Cal Time 10 01 97 11 03 41 The address should normally be set to If it is set to any other character or string the HydroScat will only acknowledge commands that begin with that string Baud rate is the rate to which the sensor is set upon startup not necessarily the current rate Use BAUD to view or adjust the current rate The three prefix characters are used to distinguish almost all messages produced by the HydroScat 2 The Data Prefix character precedes all standard data messages see D H and T and is used by the HydroScat Windows software to identify them as such The Info Prefix precedes most informational displays including those shown in this example The Error Prefix marks important warnings that demand the user s attention Cal Temp is not used in present HydroScat 2 s It is intended to serve as
11. can be loaded either directly from a connected HydroScat or from a file on the host computer To load an instrument s calibration check the Load Calibration From Instrument option while connecting to the instrument 15 section 5 4 To load a calibration from file choose Select Calibration File from the File menu If you select a new calibration file while an instrument is connected or while a raw data file 15 open HydroSoft will only load it 1f 1t 15 of a matching type HydroSoft will inform you if the type does not match It will also warn you if the serial number of the instrument does not match that contained in the calibration file but it will offer you the option of loading it even if the serial numbers do not match Once a calibration file 15 loaded it remains in effect until a different one 15 loaded When you exit HydroSoft it stores the name of the current calibration file If the Automatically recall last selected calibration file option is selected in the Preferences dialog box the file will be reloaded the next time HydroSoft starts up If you have more than one data window open in HydroSoft you can select a different calibration file for each one The most recently selected file in any window will be saved as the default 5 3 2 Viewing And Editing Calibration Data You can see the details of the current calibration by selecting View Calibration from the File Menu Normally you should not need to modify calibration
12. file name for the downloaded files The cast number will be appended to this base name to create a unique name for each cast you download If necessary click Browse and select a destination directory for the downloaded files Click Download Depending on the quantity of data and baud rate downloading may take some time Status messages and a graphical indicator will show the download progress To clear the instrument s memory after verifying the desired casts were downloaded click Delete All Click Close to dismiss the dialog box Details Depending on the number of casts stored loading the directory may take a number of seconds The status message in the upper left corner indicates if the directory is loaded as above or if it is in the process of loading The memory status line indicates how much of the instrument s memory is presently used 22 You can select arbitrary groups of casts for downloading To select a contiguous group of casts click on the first item in the group then shift click on the last item or hold down the shift key while using the arrow keys To select or unselect non contiguous casts control click on them or hold down the control key while using the arrow keys to move through the directory and press the space bar to select or unselect casts Data are always collected in raw form If the Create calibrated data files option is checked a calibrated file will also be created for each downl
13. shutter by simply supplying a voltage to it for a fixed length of time The polarity of the voltage determines whether the shutter opens or closes Electronics within the shutter sense when it reaches the intended position and disconnect power from the motor at that time Although the HydroScat 2 does not sense the shutter s actual position it keeps track of whether it was last sent an open or close command Unless it receives a direct OPEN or SHUT command see below it will not attempt to open or close a shutter that is already in the desired state 10 4 Operation Time Since the length of time it takes to reach the open or closed position varies somewhat depending on temperature pressure and wear the HydroScat applies power for at least the expected maximum time The default time is user programmable and can be stored in non volatile memory along with the sensor s other operating parameters The actual operation time is normally about 3 to 5 seconds depending on temperature voltage and pressure However programmed time should be set well above this to ensure that adequate time is available under all circumstances We recommend a setting of 8 seconds 10 5 Shutter Specific Commands These commands were introduced in version 1 80 of the HydroScat firmware These will not take effect unless the HydroScat s internal configuration memory indicates it is equipped to handle a shutter 10 5 1 SHUTTER auto time Firmware 1 80 SHUTT
14. value of 1 does not necessarily indicate invalid data 9 2 8 DepthRaw DepthRaw is reported as a signed 16 bit integer The depth in meters is calculated by depth m DepthRaw depthCal depthOff The values of depthCal and depthOff are specified in the calibration file provided with each instrument 9 2 9 TempRaw TempRaw indicates the HydroScat s internal temperature The actual temperature is calculated by Temp C TempRaw 5 10 Note that TempRaw is an unsigned byte with a range of 0 to 255 giving the calibrated temperature a range of 10 to 41 C 9 2 10 Error Each bit in the one byte error code corresponds to a particular error condition weight condition 1 high background 2 high signal 4 reference out of range not yet implemented 8 temperature out of range not yet implemented 16 primary voltage out of range not yet implemented 32 battery voltage out of range 64 log memory full 128 undefined 47 9 2 11 Checksum Checksum is the least significant byte of the unsigned sum of all the ASCII bytes preceding the checksum in the packet not including the packet flag 9 2 12 Terminator This packet and all other transmissions are terminated with a carriage return and line feed 9 3 T Packet Format firmware 1 60 and later The packet is identical to the D packet except that the resolution of the time value is extended by 2 hex digits The added digits indicate the f
15. 11 4546 8840 2393 4 47 5670 13110 1707 12730 1557 1 8128 1670 10724 1722 16239 2031 3 5068 gains 555 depth 1661 temp 176 VA 135 VB 79 VBk 53 Aux 120 gain status 1 0 1 Time is the current raw setting of the real time clock in seconds since midnight 1 1 1970 Error is a one byte variable in which each bit is a flag for a particular error condition described in section 9 2 10 In the display above error has the value 2 indicating that one or more of the signal channels saturated at some point during the sampling time The second line shows how many samples were averaged to produce the displayed data In this case the signals were averaged over 733 samples about 7 seconds at the sensor s internal 100 Hz rate and 11 samples were averaged to produce the offset figures Since the LEDs must be turned off to measure offsets only about 5 of the sensor s time is devoted to them and the number of offsets averaged 15 usually smaller than the number of signals In general the number of 42 samples differs slightly from channel to channel The sample quantities shown are averaged over all channels The next three lines show the name of each channel followed by its signal signal offset reference reference offset background radiance and normalized signal SNorm The background radiance 15 usually small in laboratory conditions The background saturates at approximately 85 on some sensors and 120 on others depending on
16. 9 4 5 VsupA VsupB Vback These show the voltages of up to three power supplies for the instrument The HydroScat only draws power from the source with the highest voltage and only one need be supplied for normal operation Different sensor configurations may assign the voltages differently The value reported is 10 time that actual applied voltage For example VsupA above is 77 Hexadecimal 119 Decimal representing 11 9 Volts 9 4 6 Aux Indicates charging current 1f any supplied to the internal batteries The value 15 840 times the charging current in amperes and normally ranges from 0 to approximately 200 mA 9 4 7 Checksum Same as D packet 9 4 8 Terminator Same as D packet 50 9 5 Calculating and b Each optical channel of each HydroScat has a unique set of calibration coefficients needed to convert its data to engineering units These coefficients are measured at the factory and stored in the instrument s memory as well as supplied in a CAL file that can be used by HydroSoft or other software The file format is described in section 9 7 The first step in processing is to convert the raw signal to the value of the volume scattering function 5 140 using 1 kr T T G d an with the following input variables doni Normalized backscatter value from HydroScat Mu from file TempCoef f in file Instrument temperature calculated a
17. ARE iscoscscscescescvesduccesceoscousvsseccedsvenssesvecssssevonseeseesechcvnavansvesscsenvesasosvecssossanssoess 13 41 INSTALLING HYDROSOPT ette reser tcrra et eee Pee Sa an CR Fes ea veda 13 4 2 REMOVING HYDROSOFT cccssssssccccececsessscececcesensnsececccecsensaaeeesececsessaucececcesesnaecececsesensaeeeeeensens 13 5 COLLECTING AND HANDLING 15 5314 PRIMARY DATA iiit ot erre heiter ase E 15 23 224 HOUSEKEEPING DATA iecit eb ere rei dee c rato ten Wee 15 3 33 CALIBRATION D ii eese test tos bee de Bann codd 15 3 3 7 Loading Calibrations usin t eet t tee nt d eh tetto 15 5 3 2 Viewing And Editing Calibration Data essere 16 544 CONNECTING AARSE dd eer ERR 16 DAD Connection Dialog aho eo e e e tete t e pr bd a Roten 17 34 2 Manual Connection vet ee e v Gee whens 17 3 4 33 COMTECHOW tm e Rn Beth es a o die eee tno 17 5 4 4 Load Calibration From Instrument Option esee 17 5151 EOGGING SETUP EE db e eie d We e Er diva na 18 5 5 1 Noise Levels and Sampling Rates sse eren ens 19 5 6 SETTING THE HYDROSCAT S REAL TIME CLOCK essent 20 5 7 LOGGING VERSUS REAL TIME 20 5 8 LOGMEMORY CAPACITY reset Re Ee voee ue tva oret einer vi dave OATES 20 5 9 USING THE MAGNETIC
18. ER 3enable auto time direction Firmware 1 84 and later Sets and displays parameters controlling the operation of the shutter If enable is zero the HydroScat 2 will behave as if it is not equipped for a shutter This is useful if you choose to deploy a shutter ready instrument without a shutter If auto 1s nonzero the shutter will open or close when casts are started or stopped and if burst mode is in effect when a burst is started or stopped Every time the shutter opens or closes power will be applied for seconds During this time no sampling will occur and the time is not counted as part of the warm up time or burst length in burst mode The recommended setting is 8 seconds see the discussion above 58 The value of direction determines polarity of voltage sent to shutter when it is opened and closed and therefore the direction in which it rotates Direction is entered and displayed as either CW for clockwise or CCW for counterclockwise These directions are defined with respect to view looking at the end of the shutter shaft as pictured in Figure 5 on page 57 and the default is counter clockwise Note however that some shutters are configured for special applications to rotate with the opposite sense To make the shutter settings completely nonvolatile use STORELOG section 8 3 21 10 5 2 OPEN time Opens the shutter applying power for time seconds The power will be applied for t
19. Each channel consists of separate source and receiver optics The source produces a beam of light in the water and the detector collects a portion of the light that 15 scattered out of that beam by the water Each source beam originates from a light emitting diode LED selected to match the desired measurement wavelength The beam from the LED enters the water at an angle approximately 20 degrees from normal The receiver consists of a prism that bends the field of view toward the source beam a band pass interference filter that determines the exact wavelength range of the measurement and lens that focuses the received rays onto a silicon detector The divergences of the source beam and receiver field of view the angles of the prisms and the distance between the source and receiver windows determine the range of scattering angles over which the measurement is made The HydroScat geometry results in a measurement centered on a scattering angle of 140 The fraction of the transmitted light scattered in the desired range of angles is extremely small and one of the prime considerations in the optical design is maximizing this inherently low throughput Thus we maintain at least a 2 cm open aperture throughout the optical path PRIMARY SENSING VOLUME RELATIVE DISTANCE Figure 1 Side View of Backscattering Measurement Geometry 1 3 Electronics The inherently low optical throughput of the backscattering measurement deman
20. H5020733 2004 10 11 dk_2 raw HS020733 2004 10 11 dk 3 raw H5020733 2004 10 11 gn raw H5020733 2004 10 11 time raw Save Processed Data Files To C Documents and Settings Administrator My Documents Browse Same location as raw files Process Close 5 11 1 Making Calibrated Data Files When Make Calibrated Files is selected you need to specify a calibration file to be used see section 5 3 for more information about calibration files You can type the path and name of the file directly or use the Browse button to open an Open File dialog box You must also select the file or files you wish to process using the familiar browsing controls The list in the center right of the dialog box shows those files that are contained in the drive and directory you specify and whose names match the File name filter you specify If Show only files matching calibration file is checked as it is by default HydroSoft will check the contents of the files and list only those that contain data from the instrument type and serial number specified by the selected calibration file You can select a single file or an arbitrary group of files from the list Select a contiguous group of files by shift clicking and select or deselect individual files by Ctrl clicking Once you start processing all the selected files will be processed The processed files will use the same base names as the source files with their ext
21. HydroScat 2 Spectral Backscattering Sensor amp Fluorometer User s Manual Revision 1 Hydro Optics Biology amp Instrumentation Laboratories www hobilabs com support a hobilabs com Current Firmware Version 1 92 Other firmware versions may differ in some respects Contact HOBI Labs for information on how to upgrade HydroScat firmware Revisions 1 December 2011 Correct equation symbols in section 9 formatting update section 2 2 H June 15 2008 Add notes about factory maintenance and cleaning windows section 2 G June 6 2007 Correct and clarify sigma correction sections 9 5 and 9 6 F October 22 2004 Update description of sigma correction to reflect changes in HydroSoft 2 7 section 9 6 Add STARTNOLOG command 8 3 19 E December 23 2002 Remove references to PDI box Add dimensions of deep sea rated version to Figure 4 page 7 Corrected time format in packet section 9 3 2 and checksums in example packets section 9 1 Add description of exponential sigma correction section 9 6 May 20 2002 Revise Shutter command section 10 and include more references to shutter throughout add oil encapsulated depth sensor 0 add note about preserving data in case of reset section 11 add to discussion of magnetic switch behavior section 5 9 update calculation of b and add description of Backscattering Parameters in HydroSoft 9 5 recommend minimum start delay and warm up tim
22. SW CH di 20 5 10 DOWNLOADING LOGGED 21 LA ooo s 21 5 Details As a3 he NAM 22 5 11 PROCESSING DOWNLOADED DATA ccccsssscececeesessscecececesssuscececcesenssseeeeececeesausceseeeceaasaeeeeesesenaas 23 5 11 1 Making Calibrated Data 24 5 11 2 Making Raw Decimal Files essen eene eterne 25 3 12 SRAW DATA FILE FORMAT eere terere sun nennen deese E eden eus 25 5 13 CALIBRATED DATA FILE FORMAT ccccssscccececsesessececeecescesseceeececceesaeceecesesenssascesescesensseeeeeeseeenees 25 6 ELECTRICAL CONNECTIONS 3 rra eea eene Po ET eae schnee caso aoo Foe oae uada vla e Foo Co S sacs o RUP 27 iii 7 bad INTERNAL BATTERY 29 Tele BATTERY 29 T2 EOWEVOLTAGE CUTOFF een ido E 30 7 3 CHARGING Sense een nn teen 30 TPA BATTERY DISABLE aaa 30 DIRECT COMMUNICATION AND COMMANDS ccssssscessssccesssccccssnscceessccccesscccessnsscecssesees 33 8 1 COMMUNICATION PROTOCOL ee dedu e ede d even 33 8 2 COMMAND CONVENTIONS 5 ss i eod reed o aia 33 83 ROUTINE COMMANDS iei cel eee ORE E ERO Ee a pe en ER Ee o 33 8 3 1 BURST on warm
23. aa 59 10 53 GE OSE time ecce A OEE 59 10 6 OTHER RELEVANT COMMANDS cccccccesssccesssscecessseccessecesesseccessececesseecessussesecsececcssseccesaseeesesaeees 59 11 TROUBLESHOOTING 61 12 CUSTOMER SER VIG E i eerteo eden oe uan ae eo Sb Leu ee e uS aea ees Pe Ee uo eR Ud e gw 63 vi 1 INTRODUCTION 1 1 Overview The HydroScat 2 is a self contained instrument for measuring optical backscattering bj at two wavelengths in natural waters Its unique optical geometry and sophisticated electronics also provide simultaneous measurement of the fluorescence excited at the longer wavelength by the shorter wavelength source The HydroScat 2 includes a depth transducer rechargeable batteries a data logger with real time clock and an external switch for controlling logging The data logger supports a wide range of sampling rates as well as burst mode sampling for collection over extended periods 1 2 Optics This brief overview introduces the key concepts necessary for understanding the HydroScat s measurements The optical principles are covered in much greater detail in Instruments and Methods for Measuring the Backward Scattering Coefficient of Ocean Waters by Robert A Maffione and David R Dana Applied Optics Vol 36 No 24 20 August 1997 The HydroScat 2 has two independent channels each sensitive to a different narrow range of optical wavelengths
24. and or by turning on the external switch the HydroScat will wait for the number of seconds specified by 18 Start Delay then data will be logged according to given Sample Period If burst mode is on the sampling continues until the Burst Length has elapsed at which time the sensor goes into its low power sleep state The bursts repeat according to the period set by Burst Interval At the beginning of each burst the HydroScat will wait for the number of seconds specified in Burst Warmup before collecting 15 first sample To guarantee that the first sample 15 valid and instrument gains are set properly the warm up should be set to 3 seconds or more Whether or not burst mode is on sampling stops upon receipt of a software stop command when the external switch is turned off or when the battery becomes exhausted In the example above the burst mode parameters are inactive because burst mode is not on To edit the burst mode parameters you must first check the Burst Mode On option If Start on power up is checked the HydroScat will begin logging each time power is applied Note however that this setting is only relevant after all power sources including internal batteries are turned off For HydroScats with internal batteries i e most HydroScats you must intentionally disable the batteries see section 7 4 for this to take effect If Make these settings nonvolatile is checked the settings will be stored in semi permanent
25. arch 2002 overcomes this limitation on instruments built since then and can be retrofitted to older instruments You can test this on your instrument by applying 14V from a power supply to the external supply input then operating the switch 5 10 Downloading Logged Data HydroSoft s Get Data From Instrument command enables you to view a list of casts stored in an instrument s memory transfer casts from the instrument to files on your computer and erase the instrument s memory Casts you transfer are stored in individual files whose location and base name you specify The cast number is appended to the name of each file 5 10 1 Basic Procedure Connect HydroScat to your computer s com port using the supplied data download cable start HydroSoft and use HydroSoft s Connect command to establish communication Select Get Data From Instrument the HydroScat menu A dialog box like following will appear 21 m HydroScat Loaded Memory Status 9783351 001471 bytes 8796 free Load Directory CE ESA y FER JE rS Sanples Delete Al Base Name q HSoft Test Files Browse Iv Create calibrated data dat files raw files are always stored 5 10 2 Logged Data Select All Use Shift click to select groups of casts Ctrl click to select or deselect individual casts Close After the directory is loaded select the cast or casts you wish to retrieve Enter a base
26. ate the HydroScat s readings into Chlorophyll concentrations Sigma Correction Parameters Sigma function for backscattering correction exp X Estimation of Kbb Mu a 04d 0 06a 2 0 6 1 0 2exp 4 440 0 014 4 400 yg 2 400 400 0 01 0 4 by bpw by p 011 b AY 0 015 Browse a c Program Files HydroSoft aStar csv Browse Restore Defaults OK Cancel 54 9 7 CAL file format Note that not all the parameters included in the CAL file are needed for the calibration procedure described above Some parameters not shown here may also appear and the sequence of parameters may change depending on the firmware version Each line may also include a comment preceded by a double slash Start General Comment Serial H2991014 Config WA4BOROFO0SOI2 Label U South Florida 4 CalTime 940441065 10 20 99 17 37 45 CalTemp 25 1 DepthCal 0 011509 Depthoff 27 776199 Channell Name bb470 Gain1 0 105786 Gain2 1 000000 Gain3 9 814222 Gain4 97 364861 Gain5 994 677307 Mu 11 57230 Sigmal 0 998000 Sigma2 0 128000 Sigma3 0 012800 SOutoff 0 000000 SInOff 0 000000 ROutOff 0 000000 RNominal 10000 000000 Beta2Bb 6 790000 Bb2c 64 000000 TempCoeff 0 000000 Channel2 etc in same format End 55 10 ANTI FOULING SHUTTER OPTION During long deployments in biologically active waters organi
27. aw reading in seconds since midnight Jan 1 1970 at the time the calibration or configuration parameters were last changed This cannot be directly entered but 15 updated automatically 8 3 12 LOG period delay sleepOnMemFull autostart burstMode burstWarmup burstDura tion burstCycle totalDuration Period 15 the time in seconds between samples that are logged and transmitted on the serial port Delay 15 the number of seconds the instrument will walt after a START command power on or magnetic switch activation before the first sample 15 logged To guarantee that the first sample collected 15 valid Delay should be set to at least 3 seconds A nonzero sleepOnMemFull value indicates that the sensor will stop logging and go into a low power sleep when the log memory fills Autostart 1f non zero indicates that logging will start with the given delay automatically when power is applied to the sensor Autostart applies primarily to HydroScats without batteries those with batteries are usually powered continuously even in sleep mode The burst mode parameters are described under the BURST command although they can also be modified using LOG The reply to the LOG command shows the settings of all the applicable parameters Sampling and Logging Parameters Log Period 1 seconds Start delay 60 seconds Sleep when memory full 1 Start on power up 0 Burst mode 1 ON Warmup time 5 seconds Burst duration 15 seconds
28. bout the equipment and procedures involved see the HOBI Labs Backscattering Calibration Manual available at www hobilabs com NOTE Even if you perform your own calibrations it is very important to return the HydroScat 2 to HOBI Labs preferably annually for a complete functional test and check out Inspection and testing by trained factory personnel can uncover items that may not be evident to users but which can affect the reliability or endurance of the instrument 2 3 General Cleaning Upon removing the instrument from the water rinse it thoroughly with fresh water and rinse the windows with distilled or deionized water Periodically inspect the windows for contamination 2 4 Windows HydroScats have acrylic windows that are easily scratched Minor scratches will not seriously compromise the measurements but the windows must be treated carefully to avoid abrasion Do not use acetone or abrasive cleaners Do not over clean the windows Unless the windows become visibly dirty during use it is usually sufficient to rinse them with clean fresh water each time the instrument is removed from the water If necessary clean them with a mild liquid soap or lens cleaning solution Occasional cleaning with alcohol is also safe but usually not necessary 2 5 Pressure Transducer If your HydroScat 2 has an encapsulated pressure transducer with a plastic wick attached use care to ensure the wick is not damaged so as to allow the silicon
29. cattering at two wavelengths and fluorescence at one wavelength The fluorescence channel is not calibrated to an absolute standard so its data are reported in arbitrary units INDICATOR MAGNETIC SWITCH ON AS SHOWN ZINC ANODE PRESSURE TRANSDUCER DRAIN HOLES OLDER MODELS ONLY LIFTING EYE MCBH8M CONNECTOR ENCAPSULATED PRESSURE TRANSDUCER NEWER MODELS Figure3 HydroScat 2 Back End Cap 2 PRECAUTIONS AND MAINTENANCE The HydroScat 2 15 a sophisticated optical instrument that requires regular care and calibration HOBI Labs is not responsible for the accuracy of data 1f you do not observe the following recommendations 2 1 Precautions Protect windows Cover instrument face whenever possible Do not use acetone to clean any part of the instrument Thoroughly clean the HydroScat with fresh water before storing it Avoid letting the sensor sit in direct sun on deck water temperature is very different from the temperature on deck let the instrument stabilize in the water for 10 minutes before collecting data See section 7 for information about maintaining internal batteries 2 2 Calibration and Factory Maintenance We recommend calibrating the HydroScat 2 every six months or 200 hours of operation whichever comes first With the proper equipment available from HOBI Labs users can perform their own calibrations For more information a
30. ch other by commas Arguments may be individually omitted in which case they will have no effect For example if a command accepts three arguments in the form comMAND argl arg2 arg3 you may adjust only arg3 by entering COMMAND arg3 8 3 Routine Commands 8 3 1 BURST on warmup duration cycle totalDuration logPeriod start Delay autoStart sleepOnMemFull Similar to LOG but lists the burst parameters first to make them easier to enter 33 In burst mode 1 e 1 on 15 nonzero upon receipt of the START command or activation of the magnetic switch the HydroScat waits for the number of seconds specified by the LOG command s startDelay parameter It then collects data until duration seconds have passed At the end of the burst it goes into low power sleep mode until cycle minutes have passed since the beginning of previous burst At the beginning of each subsequent burst it waits for warmup seconds before resuming collection guarantee the first sample is valid warmup should be set to at least 3 seconds When totalDuration hours have passed since the beginning of the first burst the HydroScat will go into an indefinite low power sleep If duration is zero burst mode will be disabled regardless of the value of on If cycle is zero the HydroScat will sleep indefinitely after only one burst If totalDuration 1s zero the total duration will not be limited Burst mode 1 ON Warmup time 5 seconds Burst duration
31. d a BNC connector with a binding post adapter for an external DC supply 27 7 INTERNAL BATTERY HydroScat 2 s are equipped with an internal rechargeable battery except upon special request The battery consists of 9 nickel cadmium Ni Cd cells that provide capacity sufficient for a day of intensive data collection With intermittent sampling and proper use of the HydroScat s low power modes it is possible to operate for days weeks or months between charges 7 1 Battery Capacity The actual capacity of the battery depends on the temperature at which it 15 charged stored and discharged Capacity is improved by charging and storage at temperatures of 20 C or less On the other hand low temperatures during discharge lower the realized capacity Peak capacity for a battery charged and discharged at room temperature is over 20 hours of continuous operation When discharged at 0 C the same charge provides at least 14 hours of operation Internal leakage causes the battery to slowly discharge even with no load The self discharge rate is highly temperature dependent After one month at 0 C the battery may lose 1096 of its charge The loss at least doubles at 20 C and continues to increase at higher temperatures Capacity also decreases slowly as the battery ages The capacity loss depends greatly on charging conditions but is typically less than 1096 after 200 charge discharge cycles and 2090 after 500 cycles Approximate discharge ti
32. d be reduced In this example channels 1 and 3 are judged to have too much gain and will be reduced by the autogain algorithm if it is enabled The next sample displayed would show those channels set to gain 4 The averaged signal levels in this example are well below saturation but as indicated by the error value of 2 some channels must have received excessive signals at some point during the sampled interval 43 9 DATA PROCESSING REFERENCE 9 1 Raw Data Formats HydroScats can produce several data packet formats as well as reply to many commands see section 8 The D data packet described below contains the primary optical and supporting data for routine data collection The packet which was introduced in firmware version 1 60 is identical to the D packet except that 1 includes higher resolution time values packets contain housekeeping data that are not needed for normal data processing but provide extra information that could be useful for trouble shooting It is advisable to save all the raw data in case any special post processing is needed For troubleshooting purposes you can view raw decimal data by using the X command section 8 4 5 Packets consist of ASCII characters Numbers are represented in hexadecimal notation Signed numbers are in 2 s complement format Transmissions always end with carriage return and line feed characters 9 2 D Packet Format 9 2 1 Example D Packet
33. data for an instrument and the fields in the Calibration dialog box are locked to discourage casual changes However you can unlock most fields by clicking on the lock icon in the dialog box Because correct calibration files are critical to the accuracy of your data use care when modifying them To reduce confusion we encourage you to enter a description in the comment field provided of any changes you make To save a copy of the currently loaded calibration select Save Calibration from the File menu 5 4 Connecting To communicate with a HydroScat HydroSoft must open the appropriate computer port at the correct baud rate The following dialog box allows you to control this process 16 5 4 1 Connection Dialog Box Connect To Instrument x Status No Connection Com Port Baud Rate Instrument Type 1 9600 unknown v Load Calibration From Instrument This dialog box appears each time you select Connect from Instrument menu click on Connect button in data window attempt an operation that requires a connection if a connection has not yet been established 5 4 2 Manual Connection If you click the Connect button HydroSoft will open the currently selected port at the selected baud rate Normally you need not select an instrument type because HydroSoft will always request identification information from the instrument If it receives a reply sufficient to identify the instr
34. ds are not needed for routine operations and should be used with great care 8 4 1 AGAIN channel auto Turns automatic gain control on 1f auto 15 nonzero or off 1f auto 15 zero The channel argument specifies to which channel the auto argument applies The channels are numbered 1 through 3 Setting channel to zero causes the auto argument to apply to all channels Reply for the default setting of autogain active for all channels autogains 111 8 4 2 BAUD rate Immediately sets the baud rate at which the instrument communicates If sent without an argument reports the current baud rate setting Valid rates are 4800 9600 19200 38400 and 57600 The actual baud rate set by the instrument 15 usually slightly different from these rates although you must specify one of the standard rates exactly When the HydroScat states a baud rate 1t shows both the nominal and actual values The deviation in actual baud rates is well within the acceptable tolerances for communication with a computer Reply if no rate specified Baud rate 9583 9600 Reply 1f rate 15 19200 Changing rate to 19166 19200 8 4 3 GAlN channel gain Sets the given channel 1 through 3 to the given gain 1 through 5 If channel 15 zero all channels are set to the given gain 40 Because channels 2 and 3 channel 3 measuring fluorescence share optical front end their gains are always identical Reply gains 544 Gain is reported
35. ds very sensitive electronics In clear water the backscattering signals arriving on the detector may be as low as a few picowatts At the same time natural background light may be orders of magnitude larger To separate backscattering signals from background light the LEDs are modulated at audio frequencies and synchronous receiver electronics used to discriminate against interfering signals Each channel has a different frequency to prevent any crosstalk between channels This also allows us to discriminate between backscattering and fluorescence see section 1 4 To allow measurement in a wide range of waters and to accommodate the requirements of our calibration procedure the gain of each channel can be set to one of five settings spaced a decade apart Only three of these settings are used in normal measurement situations the lowest two are used primarily for calibration The HydroScat normally selects the appropriate gain automatically based on the amount of backscattering detected as well as the amount of background light In order to compensate for residual electronic offsets HydroScat periodically turns off each LED briefly to measure the receiver output in the absence of signal The LEDs are turned off for 0 1 second approximately every 2 seconds and the resulting offsets are continuously averaged and subtracted from the signals Note that this is not the modulation referred to previously that separates the backscatter signa
36. e battery disable function 31 8 DIRECT COMMUNICATION AND COMMANDS HydroScats are configured and controlled with commands sent via their serial communication port When you use HydroSoft the commands needed for routine operation are generated automatically and you do not need to know the details However you can type commands manually and view HydroScat s replies directly via HydroSoft s terminal window a generic terminal program Some less common commands are accessible only through this method 8 1 Communication Protocol HydroScats communicate through a standard RS 232 serial connection with 8 data bits no parity one stop bit and no handshaking The default baud rate 15 9600 but 1 can be set to other standard rates up to 57600 see section 8 4 2 8 2 Command Conventions The HydroScat waits until it receives a carriage return line feed or other control character before responding to a command It responds to every command but does not echo characters when it receives them If it receives a command it does not understand it will echo the command followed by a question mark The HydroScat s responses usually start with an apostrophe Error messages start with an exclamation point and primary data messages start with an asterisk Commands are insensitive to case They are shown below in upper case for clarity Some commands accept arguments which are separated from the base command and from ea
37. e of 3 seconds grammatical and format corrections February 20 2002 Update addresses contact information June 15 2001 Add anti fouling shutter section 10 and elsewhere February 16 2001 Start of revision tracking Extensive reorganization changes to incorporate HydroSoft separate HydroScat 2 from HydroScat 6 TABLE OF CONTENTS T INTRODUCTION cm 1 Il OVERVIEW 1 1247 OPTICA dd a d de tl A A 1 1 3 EBECIRONICS ete E E E E E te 2 1 4 FLUORESCENCE enses 3 2 PRECAUTIONS AND MAINTENANCE ccssssscsssssscsscccsscssssensccsescsscsseecescssssssesceesssssssssenscessecs 5 2 PRECAUTIONS cis 5 2 2 CALIBRATION AND FACTORY 5 2 34 GENERAL CLEANING tinta ta ac aida 5 2 4 E AELA ESEE O E TE OET E EN dat Sater 6 2 59 PRESSURE TRANSDUCER ads 6 2 6 CONNECTOR A ne an lid amber i ett etd vtov lat 6 2 7 MOUNTING AND DEPLOYMENT aee n eer eerie etn ted 6 3 QUICKSTART u a NO 9 3312 SETUP NN 9 3 2 Y COLLECTING DATA ee ae I e n eq a MEE 9 3 3 DOWNLOADING DATA FROM THE 10 3 4 DISCONNECTING dina 10 3 5 SWITCH ACTIVATED LOGGING SEE ALSO SECTION 5 9 nennen eren 10 4 HYDROSOFT SOFTW
38. e oil to leak out If your HydroScat 2 has the older style of transducer under the suspension eye see Figure 3 on page 4 flush the pressure transducer with fresh water when rinsing the instrument If possible spray water directly into the drain holes but not at very high pressure 2 6 Connector Occasionally apply silicone lubricant to the connector pins The connector should mate smoothly without great force Well lubricated connectors also disconnect fairly easily so use the connector locking sleeve during deployment 2 7 Mounting and Deployment The HydroScat can be suspended vertically from the metal eye on the connector end cap or strapped to another support If mounting it to another structure protect the finish on the case from direct metal contact To ensure that the HydroScat does not detect reflections from any objects keep a 30 degree cone in front of the windows clear for at least 1 meter Even objects that appear very non reflective or are well out of the nominal sampling volume can create substantial offsets in the backscattering measurement It is usually permissible to violate this conservative 30 degree limit but you should verify by experiment that the instrument s readings are not elevated if you do so It is usually preferable for the sensor to face directly down in the water to minimize the effect of background illumination However in shallow water over a reflective bottom under bright solar illumination lig
39. eiving the instrument HOBI Labs will inspect it and provide you with an estimated cost for required or recommended repairs if any Repairs will not be started until you approve the cost estimate and turnaround time For technical support or questions about your instrument contact our technical support department at support hobilabs com or consult the support section of www hobilabs com 63
40. ensions set to dat They will be saved in the directory you specify If 24 you wish to save them in same directory as raw files from which they are generated you can avoid having to select that directory manually by checking the Same location as raw files option 5 11 2 Making Raw Decimal Files The process for making raw decimal files is identical to that described above except that there is no need for a calibration file Controls relating to the calibration file will thus be disabled When you select the Make Raw Decimal Files option an additional Include Housekeeping checkbox will appear allowing you to control whether housekeeping data will be included in the file in addition to the primary optical data 5 12 Raw Data File Format HydroSoft names raw data files with the extension RAW Raw files start with a header like the following Header HydroSoftVersion 2 02 CreationDate 02 12 01 23 00 55 FileType raw DeviceType HydroScat 2 DataSource HydroScat 2 CalSource D Program Files HOBI Labs temp cal Serial H2000123 1494 5283 EndHeader Future versions of HydroSoft may include additional information between the Header and EndHeader markers In any case everything following the end marker is included in the exact form in which 1t was received from the HydroScat For information on the raw data formats see section 9 5 13 Calibrated Data File Format HydroSoft normally
41. eply Sampling stopped 8 3 21 STORELOG Stores the current settings of the log parameters see the LOG command on page 22 in non volatile memory so that they will remain in effect even when power is removed from the sensor Reply Storing OK 8 3 22 T Transmits a T packet of hexadecimal format See section 9 3 for details of the data format 8 3 23 TIME hh mm ss Sets the real time clock to the given time does not affect the date If no time is given in the command simply reports the current setting The real time clock is reset whenever power is turned off to the sensor Setting it accurately is not necessary to the operation of the sensor but may be useful for keeping track of logged data Reply 05 01 97 14 51 02 39 8 3 24 TIMERES mode Causes the HydroScat to report time in high resolution 0 01 s or low resolution 1 s mode Specifying a mode of H high or 1 will enable the high resolution mode Specifying a mode of L low or 0 off will disable the high resolution mode In high resolution mode the data packet format is slightly different and is denoted by T instead of D at the beginning of the line See section 9 1 for details of data formats Reply to TIMERES H or TIMERES 1 Time Resolution high 0 01 second Reply to TIMERES L or TIMERES 0 8 4 Time Resolution low 1 second Special Purpose Commands The following comman
42. gma corrected form then in uncorrected form 140 values with and without sigma correction are also included if the include beta in files option is selected in the Backscattering Parameters dialog section 9 5 26 6 ELECTRICAL CONNECTIONS A HydroScat can be powered from three sources 1 external 10V to 15V supply 2 internal battery 3 battery charger Any combination of these source may be safely connected simultaneously Power will be drawn from the source with the highest voltage Nominal operating power draw is 1W HydroScats can be configured to use either RS232 or RS485 protocols for communication In the RS232 configuration the HydroScat can communicate directly through a standard computer serial port In the RS485 configuration a converter or interface card must be provided to allow communication with an RS232 port The HydroScat 2 has a single SubConn MCBH8M connector mate for power and data connections as shown below PIN FUNCTION O 1 Supply voltage 10 to 15 V 2 2 5 3 RS232 Receive or RS485A MCBH8M 4 RS232 Transmit or RS485B FACE VIEW OF PINS 5 Battery charging input 12 to 24 V 6 Shutter Drive optional 7 Shutter Drive optional 8 Battery Disable The standard Power Data Interface cable supplied with HydroScats splits into a DB9 for communication a barrel connector the battery charger an
43. his time even if the firmware s memory indicates the shutter is already open If time is zero or unspecified the default time set by SHUTTER will be used 10 5 3 CLOSE time Closes the shutter applying power for time seconds The power will be applied for this time even if firmware s memory indicates the shutter is already closed If time is zero or unspecified the default time set by SHUTTER will be used 10 6 Other Relevant Commands The shutter settings and current state are reported after the other logging parameters in response to the LOG 8 3 12 and BURST 8 3 1 commands The shutter settings are also stored along with the log and burst parameters in response to STORELOG 8 3 21 The response from GCF global configuration 8 4 4 indicates whether the HydroScat is equipped for a shutter p9 11 TROUBLESHOOTING If your HydroScat 2 does not respond to its external switch and HydroSoft is unable to wake and detect it you may need to reset its microprocessor This process will preserve logged data in RAM 1 Connect the battery charger or another external power source 2 Check that the HydroScat is properly connected to the computer 3 Select the Reset command from HydroSoft s Instrument HydroScat menu making sure that it is addressing the port to which the HydroScat 15 connected 4 Wait for 60 seconds after the reset completes before attempting to reconnect If the instrument still does not
44. ht reflected into the windows may cause high noise levels or in extreme cases saturation such situations it may be advantageous to mount the sensor horizontally so that the backscattering receivers do not face the bottom Some experimentation may be required in such cases HydroScats equipped with internal batteries deployed with only mechanical cable or attached to an existing package without additional cabling If HydroScat 15 attached to an existing package make sure that the field of view of the sensor is unobstructed as mentioned above MCBH8M Connector Standard version 9 00 22 9 cm p d Deep Ocean version 10 9 27 7 cm nd KEEP 30 CONE CLEAR Eta E OBJECTS Bee O er dug 5 E m s N Frage Io Pe Ser bc 2 40 F SNS 22723 Mo Pa Dig a AS RCM 28 yee EN er ga no Figure 4 HydroScat 2 Side View 3 1 3 2 3 QUICK START Setup 1 Install HydroSoft on your computer see section 4 1 or the HydroSoft manual 2 Connect the supplied data download charging cable to the appropriate port on your computer 3 Connect the cable to the underwater connector on the HydroScat 4 Plug the cord from the battery charger transformer into the barrel connector on the data cable 5 Plug the battery charger t
45. icating with HydroScats as well as other instruments Instructions in this manual assume you are using HydroSoft to communicate with your HydroScat and cover its primary functions You may wish to consult the separate HydroSoft manual for a more complete description and details 4 1 Installing HydroSoft HydroSoft is supplied on a CD ROM with new instruments and can be supplied on floppy disks by request We also recommend you visit our web site www hobilabs com to check for downloadable updates to HydroSoft It is installed using a procedure that is familiar to most Windows users 1 Run InstallHydroSoft exe from CD ROM or from your computer if you have received it through the Internet 2 Click Next button in the installer s Welcome dialog box 3 Decide whether you would like the HydroSoft application stored in the default directory shown normally c program Labs If not click the Browse button to select a different directory or type the name of a new directory you would like to create 4 Click Next to start the installation 5 When the installation is complete click Finish to exit It is not normally necessary to reboot your computer unless the installer program explicitly instructs you to 4 2 Removing HydroSoft 1 From the Start menu select Settings then Control Panel 2 Double click on the Add Remove Programs icon 3 Select HydroSoft from the li
46. is a complicated function of sensor s optical geometry but can be closely approximated by o K ki exp where K is the coefficient of attenuation for light traveling from the sensor to the sensing volume and back is characteristic of the specific instrument and is included in its calibration file k is set so as to satisfy the requirement that o K x 1 where is the attenuation excluding that of pure water of water in which the instrument was calibrated That is k exp k When the calibration is performed with well filtered water is near zero and k is for practical purposes 1 at all wavelengths Since HydroScats do not make a direct measurements of attenuation their Ky is estimated from K 0 4 If measurements of and b are available they can be used to calculate sigma corrections with the best possible accuracy However within HydroSoft a 1s estimated from a priori data and b is estimated from the measured is calculated from the following model 3 a A 0 06 4 1 0 2 exp y 4440 400 4 400 where the first term accounts for the contribution of chlorophyll and other factors that correlate with chlorophyll and the second term accounts for detrital material a A is a function determined empirically by Prieur and Sathyendranath and modified by Morels C is the chlorophyll concentration in mg
47. l packet of housekeeping information See section 9 4 for details of the packet format 8 3 11 ID ID displays identifying information about the sensor This information can only be set at the factory except for the address which can be set with the GCF command section 8 4 4 It replies in this format Identification Model HS2 S N H297074 Config W1B2R112P2 ID Hobi One Address Maximum Depth 200 m Firmware 1 77 Cal Time 13660 Model and serial number are self explanatory The config string describes the sensor s hardware configuration Among other things it indicates the wavelength set quantity of RAM communication protocol and whether it has an internal battery ID is simply an identifying name which we usually fill with the name of the purchasing institution Address 15 used when several instruments share communication lines The default setting for all HydroScats is which indicates no address is required If an address other than is specified the HydroScat will respond only to commands that begin with that address Not all HydroScats have the same warranted depth rating so maximum depth is recorded here along with the sensor s other attributes The firmware version number displayed is programmed into the firmware s source code and therefore cannot be changed except by installing different firmware 36 The calibration time shown is in real time clock s r
48. ls from each other and from background radiance those modulations are too rapid to be visible SOURCE 1 Blue O SOURCE DETECTOR 2 Red 2 Red DETECTOR 1 Blue Figure 2 HydroScat 2 Front End Cap 1 4 Fluorescence Measurements The HydroScat is optimized for measuring elastic backscattering but offers a secondary capability of measuring fluorescence Because each LED in the HydroScat is modulated at its own frequency fluorescence excited by a particular channel can be identified by the excitation channel s characteristic frequency even though its emission falls into the optical bandwidth of another channel The HydroScat receiver channels can be tuned under software control to the frequency of another channel s source allowing them to detect fluorescence instead of backscattering If the field of view of a channel intersects the beam produced by another channel it can collect fluorescence from that channel as efficiently as it does backscattering from its own source The HydroScat 2 s two channels are configured with crossing beams and fields of view see Figure 2 so that the longer wavelength channel usually 676 nm detects both backscattering from its own source and fluorescence excited by shorter wavelength source usually 470 nm The received signal from long wavelength channel 15 sent to two sets of detection electronics one tuned to each source Thus the HydroScat 2 simultaneously measures backs
49. m which can be set by the user as can Kos Ya a4 400 2 Prior to 2 7 was reckoned including the contribution of pure water Thus it and k differed considerably at different wavelengths and the value of k appropriate to each channel was included in the calibration file Starting with version 2 7 is defined to include only attenuation above and beyond that of pure water Prior to HydroSoft 2 7 the equation for absorption also included a term for pure water An optical classification of coastal and oceanic waters based on the specific spectral absorption curves of phytoplankton pigments dissolved organic matter and other particulate materials Limnol Oceangr 26 4 671 689 5 Light marine photosynthesis a spectral model with geochemical and climatological implications Prog Oceanogr 26 263 53 b is estimated from b b b b where b is the backscattering probability which can be set by the user The numerator of this expression is the uncorrected b excluding that of pure water The Sigma Correction Parameters dialog box is shown below with typical settings for a HydroScat sensor The default settings are appropriate for most cases The main exception is it may be appropriate to adjust the value of C if Chlorophyll levels are high and can be estimated HydroScats that are appropriately configured may provide this information but the user must provide a calibration to transl
50. me for the battery can be calculated as follows Please note however that it is not possible to accurately account for all the factors that affect battery capacity so you should use these calculations with caution and temper them with your own experience First calculate the equivalent total current drain for your sampling schedule t active t I equiv 1 standby sample total where is the fraction of the deployment time during which the sensor will be active In burst mode this will be the sum of the burst warm up time and burst length divided by the burst interval For continuous collection its value is 1 Isample typically averages 95 mA over the course of the battery s discharge Given I equiv 29 C total equiv where is the battery capacity with units of current time 1 4 and both vary with temperature The following table shows typical values for a new battery Temperature T standby 2000 mAhr 1 0 10 2100 mAhr 1 1 mA 20 2200 mAhr 1 2 mA 30 2300 mAhr 1 6 For example in continuous use at 10 we would predict endurance of about 2100 mAhr 96 mA 22 hours For a burst mode application with active time of 20 seconds per hour at 30 Lequiy would be 1 6 mA 95 mA 20 3600 2 1 mA Total duration would be 2300 mA hr 2 1 mA 1100 hrs or about 45 days 7 2 Low Voltage Cutoff When the batter
51. memory and will remain in effect even if the internal computer is reset or all power is removed from the instrument If your HydroScat is equipped for an anti fouling shutter see section 10 the dialog box will expand to show the shutter parameters Before logging you may wish to download and clear data from the HydroScat s memory see section 5 10 5 5 1 Noise Levels and Sampling Rates The backscattering measurement involves extremely low light levels and several factors can contribute to noticeable noise in the measurements especially in clear water However noise in the measurements is unbiased and uncertainty can be reduced by averaging samples together or equivalently lowering the instrument s sampling rate conditions with low background light at a sampling rate of 1 Hz the RMS noise level is typically from about 0 0003 to 0 001 m depending on wavelength Wavelengths shorter than 470 nm tend toward the higher end of this range since LED and detector efficiencies fall off at shorter wavelengths High background light levels can introduce shot noise that degrades these figures In many circumstances natural variability exceeds the measurement noise In water containing significant numbers of very large particles even schools of 19 fish the data may show a background scattering level punctuated by spikes of increased scattering as individual large particles pass through the sampling volume Depending on
52. names calibrated data files with the extension DAT Calibrated data files start with a header like the following Header HydroSoftVersion 2 02 CreationDate 02 12 01 23 28 42 FileType dat DeviceType HydroScat 2 DataSource Instrument Cast 3 25 CalSource D Program Files HOBI Labs temp cal Serial H20001 Config S2B3 SigmaParams ad400 01 aStarFile D Program Files HOBI Labs aStar csv awFile D Program Files HOBI Labs aw csv bbTildeValue 015 C 1 gammad 011 gammay 014 Channels bb440 bb676 11676 ColumnHeadings Time Depth bb440 bb676 f1676 bb440uncorr bb676uncorr f1676uncorr Data 36872 9715856481 29 388 0 1 5536E 04 0 0 1 5536E 04 0 Future versions of HydroSoft may include additional information between the Header and Data markers The lines following SigmaParams are the parameters used for sigma correction of the calibrated backscattering described in section 9 6 The line following ColumnHeadings names the parameters included in the calibrated data lines Future HydroSoft files may include additional column headings and data parameters but 1f so the parameters shown here will remain in the same order Times are stored as double precision real numbers corresponding to the number of days since midnight January 1 1900 This is the native format of dates and times in Microsoft Excel Depth is in meters b is in inverse meters and is shown first in its si
53. o indicate a set of simultaneous measurements from all the channels The optional IM RAM expands this to about 65 000 samples Both RAM options depend on power from the internal batteries or another source to retain logged data 5 9 Using The Magnetic Switch The magnetic switch located on the back end cap of the HydroScat see Figure 3 on page 4 signals the sensor when to start and stop data logging An indicator dot is machined into the end cap and is exposed when the switch is in the position When switched on the HydroScat will wake and begin collecting data as if the START command were sent to it When switched off it will stop sampling and go to sleep as if the STOP and SLEEP commands were sent By using the magnetic switch one can collect an extended series of casts without connecting to a computer The starting and ending times of each cast are recorded in the log memory so that casts can be later downloaded individually or 20 as a group The sensor may wakened from sleep by command from serial port regardless of whether the switch 15 on or off However the software SLEEP command will not work if the switch is on Because the switch was designed to support operation from the internal batteries the switch as originally designed may not operate if an external source of power including batteries is connected and its voltage exceeds the voltage of the internal batteries A design change in M
54. oaded cast The calibration currently in effect for the main data window will be applied to these data see section 5 3 for more information about calibrations Because of the way HydroScat s memory is configured it is not possible to delete individual casts you can only erase the instrument s entire memory 5 11 Processing Downloaded Data While HydroSoft allows you to save calibrated data automatically at the time you collect or download data from a HydroScat you can also process raw data files using HydroSoft s Process Raw Files command This command also allows you to convert raw hexadecimal data to decimal form without calibrating them When you select Process Raw Files the following dialog box appears 23 Process Raw Data Files Processing Make Calibrated Files Make Raw Decimal Files Calibration File DAManufacturingyProductslHScatslHSe Individual Instruments HS33 IF Browse Raw Files to Process Directory containing source files al Instruments HS33 IRD2X2004 9 Service Cal Preservice Cal 2004 101 File name filter Eligible Files raw H5020733 2004 10 11 dktime_gn4_1 A Select All H5020733 2004 10 11 dktime_gn4_2 H5020733 2004 10 11 dktime an5 1 Show only files matching H5020733 2004 10 11 dktime gn5 z Select None calibration file H5020733 2004 10 11 dktime gn5 z E H5020733 2004 10 11 dktime gn5 4 se Shift click to select HS020733 2004 10 11 dk 1 raw
55. pecifies the duration of the sleep in seconds If no duration is specified the sleep interval defaults to an essentially infinite 200 000 000 seconds about six years The HydroScat wakes from its sleep when the specified number of seconds has passed or e itreceives characters through its communication port or the magnetic switch is moved to position 8 3 17 SLEEPINFO SLEEPINFO displays the time and cause of the HydroScat s last sleep and of it subsequent waking Possible causes of sleep include e receipt of the SLEEP command e movement of the magnetic switch to its off position e log memory filling up e battery voltage falling too low scheduled sleep during burst mode logging 38 8 3 18 START delay Causes the HydroScat mark the beginning of a new cast in log memory and to begin logging and transmitting data according to the parameters set with the LOG BURST command Logging will start after delay seconds or if no delay 15 specified after the start delay specified by the LOG command START has effect if the HydroScat is already logging Reply Sampling starts in delay seconds 8 3 19 STARTNOLOG delay added in firmware 1 80 Identical to START except that data collected will not be logged in internal memory 8 3 20 STOP Causes the HydroScat to immediately cease logging and transmitting data Also marks the end of the current cast if any in the log directory R
56. ractional time in hundredths of seconds In the example below the fractional time of 1A indicates 0 26 seconds Fractional time values greater than 99 decimal 63 hex are undefined 9 3 1 Example Packet T346A023C1A055613CC1606000000000000000000005550000006488700F3 lt CR gt lt LF gt 9 3 2 T Packet Structure Parameter Type ASCII ASCII Example Bytes Packet Flag PacketiD char T Time signed HHHHHHHH 8 346 023 Time Snomi signed HHH 4 05 Snom2 signed HHHH 4 1300 Snom3 HHHH_ 4 1606 Snorm4 signed HHHH 0000 Snorms signed H 4 0000 Snom signed H 4 0000 Snom7 soned m 4 0000 Mee Snorm amp 0000 Gain Status1 nibble 5 Gain Status2 5 Gain Status3 5 Gain Status4 0 Gain Status6 0 Gain Status6 0 Gain Status7 0 Gain Status8 nibble H 1 0 48 TampRaw ignei e 9 2 Terminator onset 2 Fed set to zero by HydroScat 2 9 4 H Packet Format 9 4 1 Example H Packet H346A023C060F4B510647FE04A6545C066EFF04F34007050EFE06C837AF06B5FE05857 89705C6FF04F35A8807C9FF000000000000000000000000000077210B069122 lt CR gt lt LF gt Param type Jasch ASCII Bytes Example dee er Time sioned HHHHHHHH 8 34640230 Soom signed 4 Rel signed 4 4851 Rerom signed 0647
57. ransformer into a 120 VAC jack 6 Run HydroSoft by selecting it on the Windows Start menu 7 Click or select Connect from the Instrument Menu 8 Click the Search button 9 After a short time HydroSoft should identify the instrument load its calibration and close the Connect dialog box If your HydroScat is equipped for an anti fouling shutter see section 10 and programmed to open the shutter at the time it wakes up it may not respond to HydroSoft s initial query and you may need to repeat the search 10 Select Set Date Time from the HydroScat menu 11 Click Set Time to synchronize the HydroScat clock with your computer s clock This will take several seconds Then click Close to close the Date Time dialog box Collecting Data 12 Select Sampling Options from the HydroScat menu 13 For testing purposes we recommend the following settings Sample Rate 2 per second Start Delay 0 seconds Burst mode unchecked 14 Select Plot Vs Time from the Graph menu 3 3 3 4 3 5 15 Click start or select Start from the HydroScat menu This will cause data to be logged in the logging memory as well as sent to HydroSoft 16 If no data are visible after a short time click El and the plot will zoom as needed to show all data 17 To adjust the way data are displayed double click on the graph or select Properties from the Graph menu 18 Click 89 or select Stop from HydroScat menu
58. respond use this alternate procedure NOTE THAT THIS PROCEDURE WILL ERASE ANY DATA IN THE INSTRUMENT S RAM It will not affect data in flash memory if your instrument is so equipped 1 If it is possible the battery is discharged connect the charger for at least 30 to 60 minutes 2 Disconnect the charger from AC power 3 Disconnect the data cable from the HydroScat s underwater connector 4 Plug the special dummy plug designated by a red handle into the underwater connector for 10 seconds If the special plug is not available directly short pins 2 and 8 together see section 6 5 Remove the dummy plug and reconnect the data cable to the computer 6 Attempt to connect using HydroSoft 61 12 CUSTOMER SERVICE If your HydroScat needs to be returned to HOBI Labs for repair maintenance or calibration contact HOBI Labs customer service service hobilabs com or call the main office or go to the support section at www hobilabs com with the following information e Instrument Serial Number e Reason for return Method of return Federal Express United Parcel Service etc Point of contact Date needed standard turnaround is three weeks e Delivery address HOBI Labs will provide you with a returned material authorization RMA number so that your instrument will be properly identified when we receive it PLEASE DO NOT RETURN ANY EQUIPMENT TO HOBI LABS WITHOUT AN RMA NUMBER As soon as possible after rec
59. s shown above Toal CalTemp from cal file Gg Gain ratio for gain g Gain1 5 from cal file Rio Nominal reference value Rnom from file The u subscript here stands for uncorrected indicating that the sigma correction described in section 9 6 has not yet been applied The backscattering coefficient b is estimated from 140 using the method described in Instruments and Methods for Measuring the Backward Scattering Coefficient of Ocean Waters by Robert A Maffione and David Dana Applied Optics Vol 36 No 24 20 August 1997 according to the following expression b 27X 5 140 1 40 b with the following additional inputs p Constant of proportionality between 140 and b for particle scattering The default value is appropriate for most cases but can be changed in the backscattering parameters dialog box shown below In cal files the value 277 is stored with the name Beta2Bb 8 140 Volume scattering of pure water at 140 degrees Backscattering coefficient of pure water 51 Normally value of used in this equation would include sigma correction explained in the following section The pure water scattering values and bpw are calculated by HydroSoft according to parameters set in the dialog shown below This is displayed in response to the Backscattering Parameters command on the File menu The default values are from A Morel Optical Properties of P
60. sms can grow on the windows and severely degrade the HydroScat s performance To prevent this the HydroScat 2 can be equipped with a mechanical shutter that covers the windows with a copper plate when the sensor is not sampling The shutter 15 powered and controlled by the HydroScat 2 whether from its internal batteries or from an external source 10 1 Description The shutter is a separate device that mounts beside the HydroScat 2 The body of the shutter is 5 7 cm 2 37 in diameter and 12 1 cm 4 8 long The shutter blade covers the four windows on the face of the sensor when it 1s closed and rotates approximately 70 degrees when fully open It does not touch the face of the sensor but leaves a gap of a few millimeters When equipped with a shutter the HydroScat 2 is normally also outfitted with a copper face plate so although water can flow through the gap it provides a very inhospitable environment for growth Figure 5 Side View and Face View of HydroScat 2 with Shutter 10 2 Wiring Pins 6 and 7 on the HydroScat 2 s MCBH8M connector must be wired to pins 1 and 2 respectively on the shutter s MCBH2M connector For a deployment powered by the HydroScat s internal batteries a short jumper cable can be used to make these connections power must be supplied externally or if 57 communication with HydroScat 15 required while 1t operates a Y cable must be used 10 3 Operation The HydroScat 2 controls the
61. st of programs 4 Click the Add remove button OR 1 Open the directory into which you installed HydroSoft 2 Double click on the unwise exe icon which runs the uninstaller 13 5 COLLECTING AND HANDLING DATA 5 1 Primary Data The primary data reported in every sample are e date and time e raw scattering for each channel e the gain of each scattering channel e pressure and e internal instrument temperature 5 2 Housekeeping Data HydroScats record certain housekeeping parameters that are not required for normal data processing but can be valuable for troubleshooting and for evaluating the health of the sensor They are e battery and external supply voltages e background radiance on the detectors in arbitrary units e reference measurements of the LED outputs and e signal offsets Normally the housekeeping data are logged at one tenth the rate of the main data That is every ten samples are followed by one housekeeping sample 5 3 Calibration Data HydroScats data are transmitted in a partially processed hexadecimal form which must be converted to calibrated units The coefficients required for this conversion are unique to each instrument and may be revised from time to time when the instrument is recalibrated HydroSoft requires an appropriate calibration to be loaded before it can plot or store calibrated data from an instrument or raw data file 5 3 1 Loading Calibrations Calibrations
62. these parameters in the following dialog box which appears when you select Sampling Options from the HydroScat menu Sampling Options x Sample Rate 2 00 per second Sample Period 0 50 seconds Start Delay 10 seconds sleep when memory fills Start on power up Burst mode on Burst length 105 seconds Burst interval 80 minutes Burst Warmup 10 seconds Total Duration hours Make these settings nonvolatile Apply Close When Sampling Options dialog is first open it may take several seconds for the current settings to be retrieved from the HydroScat Similarly when you click the Apply button there will be a noticeable delay while HydroSoft transmits then confirms the new settings This confirmation is important because it allows you to check that the settings were entered as you intended The HydroScat may reject settings it cannot support for example burst lengths that are longer than the burst interval Sample Rate and Sample Period by definition have an inverse relationship Changes you make to one will automatically affect the other Note however that the period which has a resolution of 0 01 second is the controlling parameter Therefore some exact sample rates are not available For example if you enter a rate of 3 per second the calculated period will be rounded to 0 33 s and the rate will be set to 3 03 per second When logging is started either by software comm
63. ument it will proceed with the connection and close the dialog box If not 1t will notify you and ask whether to open the connection anyway In you instruct it to it will proceed on the assumption that an instrument of the type you designate 15 connected If your HydroScat is equipped for an anti fouling shutter see section 10 under some circumstances its response to HydroSoft s query may be delayed by the process of opening the shutter and HydroSoft may report that no instrument was detected In this case simply click the Connect button again 5 4 3 Search Connection If you click Search HydroSoft will ignore the selected port and baud rate and attempt a connection to each port at each baud rate from 4800 to 57600 until it receives valid identifying information from an instrument The dialog box will automatically close if a valid connection is found 5 4 4 Load Calibration From Instrument Option If Load Calibration From Instrument is checked at the time an instrument is connected HydroSoft will prompt the instrument to transmit the calibration information stored in the instrument s memory This will override the currently 17 selected calibration file if any section 5 3 for more information about calibration files 5 5 Logging Setup HydroScats can be programmed to collect data continuously at rates from 0 1 Hz to 10 Hz or intermittently to allow autonomous logging for long periods In HydroSoft you can set
64. up duration cycle totalDuration logPeriod startDelay autoStart sleepOnMem Full 33 8 3522 CHANNELS Zst an aan od 34 833 YGEEARRAM id te to eset obere tiere v cout 34 832 GDEAREOG S rte A lated oed eol 35 83 35 CEOSE me i E 35 83 0 Dieses 35 8 3 7 mm dd yyyy hhmm SS A ete A A ct ee esee tenta 35 333 D a A A 35 9 29 90 DOWNLOAD ast ee adi 35 BLO AL TE 36 SALE SE RE ee clas 36 8 3 12 LOG period delay sleepOnMemFull autostart burstMode burstWarmup burstDuration burstCycle totalDuration 37 8813 OPEN AMen 0 20 37 83 14 a RAM AAA E 37 6 3 15 SHUTTER auto time Firmware 1 80 38 0 9 16 SLE ERS COS Gott etos rete enn f 38 SLEEPING O cocinan toco Ste Eat de eode dete T dt IO 38 93 18 START OLY A A te 39 8 3 19 STARTNOLOG delay added in firmware 1 80 eee 39 63 20 STO Praia 39 SSTORELOG
65. ure Water and Pure Sea Water Optical Aspects of Oceanography M G Jerlov and E S Nielsen eds Academic Press New York 1974 chap 1 pp 1 24 However by selecting the custom option you can modify the model For special applications you can also remove the pure water factor entirely by setting the custom parameters to zero Backscattering Parameters Backscattering coefficient calculation Pure water scattering calculation 2 8 8 5 B CO DE C Morel Salt Water C Morel Fresh Water C Custom Use values from calibration file ib By Ao paseos _ Use this value b Ay R5004 _ Ag Es About Cancel 9 6 Sigma Correction Sigma correction is an adjustment to improve the accuracy of backscattering measurements in highly attenuating water Some light that would otherwise be detected as backscattering is lost to attenuation in the water between the instrument and the detection volume causing backscattering to be underestimated We compensate for this applying the following correction B o K B where p is the uncorrected backscattering The sigma corrected f can be used in the equation for b above to produce sigma corrected by 1 Versions of HydroSoft prior to 2 5 used a third order polynomial approximation for sigma and the current version still uses this if the constant kexp is not present in an instrument s calibration data 52 o K
66. whenever power is turned off to the sensor Setting it accurately is not necessary to the operation of the sensor but may be useful for keeping track of logged data In the Crosscut terminal program the host computer s date and time for this command can be entered by pressing Alt D Reply 05 01 97 14 51 02 8 3 8 DIR Displays a directory of the casts currently stored in memory Reply Cast Start Time Duration Samples Y 1 mm dd yyyy hh mm ss 2 3 hrs 12 345 x 2 mm dd yyyy hh mm ss 23 1 mins 3 456 Note that the duration is calculated from the time tags associated with the first and last packets in the cast Ifthe user changed the setting of the HydroScat clock while a cast was in progress the duration displayed may not make sense 8 3 9 DOWNLOAD cast Causes the HydroScat to transmit data stored in its log RAM Cast is the number of a cast to transmit Use DIR to view the available casts If no argument 35 15 given transmits entire contents of memory This command does not change the contents of log memory Reply If a valid cast number is specified raw data packets in the same form as produced by the sensor in real time You can interrupt a download in progress without affecting the contents of memory by sending a control C character to the HydroScat Because RS485 cannot support simultaneous two way transmission this works only on sensors with RS232 interfaces 8 3 10 H Transmits a hexadecima
67. which components are installed on the motherboard SNorm is the normalized signal sent in the standard data packets see section 9 2 6 Itis calculated by Sig SigOff SigDark norm nom Ref RefOff where Rnom and SigDark are parameters from the channel calibration record Snorm is a 16 bit signed integer S The next line shows the gain settings of all the channels Gains may range from 1 the lowest to 5 The depth value shown is in raw digital counts The temperature shown is scaled to fit into an unsigned byte as when it 1s transmitted in the normal D data packet To convert it to degrees C divide by 5 and subtract 10 For example 176 corresponds to 25 2 C VA is the external voltage supplied via the HydroScat 2 s bulkhead connector This may be zero when the instrument is operating from its internal battery 15 the voltage of the internal battery is the voltage of a secondary internal battery if any these voltages are expressed in hundredths of volts For example VA above is 13 5V Aux is used to measure the battery charge current The value shown is 840 times the current in amps In this case the current is 120 840 0 14A In sensors without batteries Aux is not used Gain status indicates whether the current gain settings are appropriate to the measurement conditions A value of zero indicates gain is suitable Positive one means it should be increased and negative one means it shoul
68. y voltage falls to a degree that indicates it 15 nearly exhausted the firmware will automatically put HydroScat into an indefinite low power sleep state In this state the contents of the RAM will be preserved but no further data will be collected With its load thus reduced the battery voltage will typically recover and the battery will usually be able to preserve the memory for several weeks or longer 7 3 Charging The HydroScat 2 includes a trickle charger that recharges the battery in a maximum of 15 hours Charging continues at the same rate as long as the charger is plugged in It is safe to charge the battery indefinitely although repeated prolonged charges can eventually degrade battery capacity For best battery life we recommend that you charge on average not more than 1 5 times the time that the sensor is operated from the battery not including sleep time and occasionally allow the battery to discharge completely The actual charging time required is roughly one half the discharge time 7 4 Battery Disable The internal battery can be disconnected from the circuitry by shorting pins 2 and 8 of the bulkhead connector see section 6 using the special dummy plug 30 supplied This special plug distinguished by red handle must removed and replaced with the black generic dummy plug or a suitable cable to permit battery powered operation Some HydroScat 2 s manufactured before June 1999 did not include th
69. your application you may or may not wish to include such spikes in averaged measurements Higher sampling rates preserve the option of evaluating the character of the data before averaging or other processing 5 6 Setting the HydroScat s Real Time Clock Although it is not necessary for the sensor s operation you may wish to set the real time clock before logging Select Set Date Time from the HydroScat menu Click Set Time to synchronize the HydroScat clock with your computer s clock If you wish to set the clock to a different time reference select the Set Manually option and enter the correct date and time before clicking Set Time It takes several seconds for HydroSoft to set the clock and reconfirm the setting When it is finished click the Close button to close the dialog box 5 7 Logging Versus Real Time Data Whenever collecting data in response to a Start command from HydroSoft or from its magnetic switch HydroScats simultaneously transmit them from their serial port Data can also be collected on demand without internal logging by sending D or commands each time data are required see section 8 for information about the commands and section 9 for the data formats 5 8 Log Memory Capacity The base memory of the HydroScat 2 includes 256K of RAM of which most is reserved for data logging The base memory can hold about 15 000 samples we use the terms sample and packet interchangeably t

HydroScat-2 User`s Manual - Hobi Instrument Services

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