SCS900 Update



Trimble SCS900 Hydro updates  

Patch to SCS900 v2.71 version.

The release of SCS900 v2.71 (build number 94) has a bug which does not load the external application DLL thus preventing the SonarMite application working. This has been fixed by Trimble and released as an update patch in SCS900 (v2.71 build number 95 or later).

SonarMite application software (SCS900 v2.5 version).

The SonarMite application software has been updated to provide the time stamped data form required by the updated SCS900 application, this includes updated 'pipe' and 'socket' processes for passing data between applications. The SonarMite application has been tied to the following operating systems ...

bulletPC Version - Windows Vista, TabletPC and Windows 7
bulletMobile Version - Trimble TSC2 Windows Mobile 6.0

To avoid the problems associated with applications working in forthcoming updates to these operating systems the applications have been compiled as 'standalone' with no dependence on version specific extensions to the environment.

The Trimble ACU/TCU versions have been dropped as the WinCe Operating System requires a specific compiler and software developers kit which does not warrant the low demand and high level of support required.

The properties dialog box does not show the settings used by the HPR sensor but includes prime sonar setting control settings

bulletQA control - A slider control has been added so the user can set the acceptance level for the QA value between normal and  highest value. The highest will filter out all but the very best shots based on QA
bulletSpeed of Sound - The user can set the sound velocity value between 1400-1600m/sec, the default setting being 1500 m/sec. 
bulletSocket Number The socket number used to transmit the data between applications (PC version only), default updated to #1600 to avoid confusion with earlier SCS900 versions.
bulletLatency Calculation - The user can enable/disable the Latency correction algorithm within the SCS900 extension module, unless the system is using SCS900 to measure positions this function is inoperative. 

SCS900 Extension Module DLL

Depth Time (latency) adjustment

The SCS900 extension dll is called by the main application and passed a position with a timestamp, the SonarMite extension dll adjusts the depth based on the depth timestamps to suit the timing of the position, this calculated depth is then subtracted from the current position Z value (or height) and returned to the main SCS900 application.

Estimation of delay from Ping to Depth Timestamp

As the extension dll receives its data via serial transmission and timestamps it on reception of the Linefeed character, the calculation of the delay from the depth 'start ping' time and subtracts it from the applied depth timestamp.  

Retention of raw data

bulletCustomDataField 1 = Depth subtracted from current Z value
bulletCustomDataField 2 = Current Depth QA value
bulletCustomDataField 3 = Time between Position and Depth (milliseconds).

These values can be used to reconstitute the original data if required and also estimate the applied time shift and depth QA value.

Simulation Mode

The simulation mode in menu DEVICE/TEST DATA/ has been updated to send a timestamp with the simulated depth message. This helps configure or demonstrate the system without the need for a physical SonarMite to be connected.

Modifications to QA filter settings

It was found the QA settings were previously set a little tight for reliable collection of data. The settings were made on the basis that reliable data would be required under the following conditions ...


SCS900 would be used in turbid water conditions in a construction environment.


It would be unlikely the software would be used in depths greater than 25m.

As there were several situations in which this was not the case and data was filtered out the QA filter slider has been modified for a wider range of operation and that a windows error beep is also sounded if data fails to pass the filter settings. Previously the slider filter point ranged from QA values 80 to 110, the new settings are set for a range of 40 through to 100.

 Explanation of the QA value

The QA value is a numeric representation of the inverse gain applied to the sonar transmission in order to maintain minimum beamwidth. In simple terms more power has to be applied in bad conditions to achieve the same return. The value of this number is complex and depends on several parameters ...


Turbidity - Quality of water in the column under the transducer.


Relection The hardness of the bottom surface.


Sound Velocity The transmission speed of sound in water.


Depth The total depth the sound has to travel through the water.

 Auto enumeration of COM: ports.

The PC software has been modified to detect and auto enumerate com ports when making a serial connection to the SonarMite. This gets over the technical problems with port numbers greater than 10 in Winows Vista and Windows 7. The PDA version is still limited to ports COM1 to COM10.


For More Information Contact:

Lymtech Ltd.
9 Gordleton Ind.Park, Sway, SO418JD, UK
Tel: +44(0)1590 681584
FAX: +44(0)1590 681902

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  Copyright2011 Lymtech LLC - Last modified: 02-07-2011