Driver to decode profile data (up to 799 beams) from a Tritech SeaKing mechanical profiler system (model SKV4). The actual data connection with QINSy is through a Tritech SeaKing SCU3 network.
The driver will only decode a data record if Generic Device Type (source type) is either Hexadecimal 25 (SeaKing) or Hexadecimal 02 (WINSON), and Data Reply Mode is equal to 0 (ASCII).
The driver can be used in passive or active mode. When in passive mode, the timetag of the first profiler beam will be the time of arrival of the first byte at the COM port, corrected for scan duration and the latency value as entered in the Database Setup Program. When in active mode, the timetag of the first profiler beam is obtained from the "Time at Start of Scan" data field. See more information below.
The profiler system is supposed to output "raw data" (not corrected for offsets) and run in "continuous data output" mode. In case the output is "processed data", the range is converted back to milliseconds using the sound velocity value from the data record (XYZ offsets are not applied). When in active mode, a command is sent upon driver start (and reset) to activate the "continous data output". The "Set Button Bar" command is used to set the QINSy UTC time as clock time, which effectively synchronises the profiler's internal clock to the QINSy time frame. The sending of commands in active mode seems not needed in more recent Tritech units as the data output is continuous anyway and the profiler's internal clock can also be set using an NMEA ZDA message. See more information under "Online Setup".
|Driver||Tritech SeaKing SCU||Interface Type||Serial||Driver Class Type||Terminated <LF>|
|UTC Driver||Yes / No||Input / Output||Input||Executable||DrvTritechSKV4.exe|
The Observation Time is calculated as follows: In active mode, the timetag of the first profiler beam is just the "Time at Start of Scan" data field. In passive mode, the timetag of the first profiler beam will be the time of arrival of the first byte at the COM port, corrected for scan duration and the latency value as entered in the Database Setup Program.
The Beam Delay is calculated as follows: The first beam delay is obviously zero. Each following beam gets a beam delay by adding the Scan Duration divided by (Number of Beams - 1).
The Beam Angle is calculated as follows: The first beam angle will equal the Rotation Offset plus the Start Angle. Each following beam will be incremented by the Angle Interval. Note: If the Head Orientation is reversed then the beam angles are inverted (multiplied by -1), except with Drivers.io option 'NOREV'.
The decoded Quality Indicator (QI) can be interpreted as one flag: the brightness flag. The flag is set to 1 if the beam has got a valid travel time, 0 if the travel time is zero or invalid.
Important. Since QINSy expects the nadir beam to be 0 degrees and positive to starboard, the beam angle values in the SeaKing profiler data need to be corrected by entering appropriate transducer mounting angle offsets, apart from the mounting offsets as found during the profiler system calibration. In the most common cases, this means a 180° roll offset.
In most cases, two SeaKing profiler drivers are being used online, one for the master profiler head and one for the slave profiler head. Often there is also a Tritech SCU-3 Bathy driver interfaced to the same SCU3 system. It is important that only one of these drivers is sending UTC time commands, i.e. is started in active mode with a two-way cable connection. Make sure that this cable is not splitted to any other COM port, otherwise the UTC time command will probably not reach the Tritech SCU system.
The other driver(s) can also be used in active mode, so that the time tag from the data records is decoded, but one must make sure to use one-way cables for these other connections, so that the UTC time commands will not reach the SCU. Also make sure that the SCU is in "continuous data output" mode.
With newer models the timing can come from an NMEA ZDA and then it is not necessary that QINSy sends the time command and in that case only one-way cables should be used for all systems connected to the UTC driver.
Drivers IO Notes
Command line parameter "N", where N should be replaced by a number, is interpreted by the driver as a slot number. Only profiler system reply data records for this particular slot are decoded.
Command line parameter "ACT" will start the driver in active mode, i.e. the driver will send the QINSy time to the SeaKing SCU system every minute. The driver will also send a command to the SCU system to set it to "continuous data output" mode. Command line parameter "PAS" will start the driver in passive mode, i.e. the driver will not send time messages for synchronisation purposes.
Command line parameter "OI" indicates that time tags are obtained from preceding "OiSTAR" headers, if available. Time tags are corrected for scan duration if driver runs in passive mode.
Command line parameter "NOREV" will not invert the beam angles (not multiply them by -1) if the head orientation is reversed, as indicated by bit 0 of the Profiler Head Orientation Mode data field.
Example. "DrvTritechSKV4.exe 4 ACT" will start driver in active mode, using profile data from slot 4 only.
Note. By default (no Drivers.io options), driver will start in passive mode, listening to master slot number 2.
Important. Since 2004-Jul-09, the Drivers.io option "NOREV" is added to all Tritech SeaKing drivers. According to Tritech International Ltd, the invert flag does actually change the data in the scan, so there is no need to invert the beam angles (supposedly, the rotation offset and scan start angle are also adapted).