NOAA Photo
MK21 OCEANOGRAPHIC DATA ACQUISITION SYSTEM
Sippican’s MK21 Oceanographic Data Acquisition may also be used in aircraft with Sippican air-
System provides oceanographers, marine scientists launched expendable probes.
and ocean engineers with a versatile and low cost Software developed for use with Sippican
capability to collect, display and store data from products provides a variety of data processing
expendable oceanographic instruments. capabilities. Profiles of ocean characteristics may
MK21 SYSTEM DESCRIPTION be displayed real-time in graphic form and the
The MK21 Oceanographic Data Acquisition data permanently stored. The user may retrieve
System is a 5/8 size PC card which is installed in this information for further analysis in several
an IBM compatible Pentium computer with an ISA formats to aid in a detailed understanding of the
slot.The MK21 uses DSP technology for onboard ocean environment.
processing and buffered I/O for operation with
Windows 95 and higher. Data collection is
controlled by the MK21 and the buffered I/O
MK21 OCEANOGRAPHIC DATA ACQUISITION SYSTEM
stores all the data until it can be read in by the
operating system. Every data point is time
stamped by an independent clock on the MK21 to
ensure no data is lost or skipped.The MK21 also
has flash memory for in system programming
capability to give users the flexibility to add newly
developed probe capability and firmware
upgrades.The MK21 is compatible with all
Sippican expendable probes and launchers.
The MK21 may be used anywhere a PC is
MK21
available aboard research vessels, on ships of
opportunity or even in small boats. The MK21
MK21 OPERATION • User-selectable features include drop rate,
The operator uses the computer keyboard probe min / max depth, auto post-
and display to input the type of probe to be processing, noise reduction, data averaging,
launched and other parameters to be stored and calculated salinity, density, and sound
with the data such as date, time and velocity profiles.
latitude/longitude in a preformatted header THE MK21 KIT CONTENTS
display. The computer performs system
The MK21 processor card, Sippican MK21
diagnostics and prelaunch tests and then
application software, MK21 to launcher
indicates the probe is ready for launch. It
interface box, and Operator’s manual.
then receives probe data during the probe
descent and displays and stores the
information.
Data is easily translated in an ASCII text
format so the user can readily generate the
measured profiles using spread sheet
applications or transfer the data to ray path
or range prediction programs.
The MK21 Windows Software has auto GPS
(NMEA 0813) input capability, selectable
IGOSS and original drop rates, a new, easier-
to-use display and improved post-processing
options.The XCTD trace shown in the
accompanying screen shot demonstrates
some of the software’s features:
• A highly visual, user-friendly display that
utilizes the capabilities of Windows
• Improved post-processing options
MK21 SYSTEM SPECIFICATIONS
PROBE TYPE XBT XSV XCTD XCTD-1 AXSV** AXCTD**
Sampling Rate 10Hz 10Hz 4Hz 4Hz 10Hz 4Hz
Vertical Resolution 60cm 60cm 100cm 17cm 60cm 100cm
(18cm for
T-11 FSXBT)
System Accuracy ±0.2°C ±0.25 m/sec ±0.035°C* ±0.02°C ±0.25 m/sec ±0.035°C
±0.035 ±0.035
mS/cm mS/cm
±0.05 PSU ±0.05 PSU
Temperature Resolution 0.01°C - 0.01°C 0.01°C - 0.01°C
Temperature Range -2 to 35°C - -2.2 to 30°C -2 to 35°C - -2.2 to 30°C
Sound Velocity Resolution - 0.04 m/sec 0.05 m/sec - 0.04 m/sec 0.05 m/sec
Sound Velocity Range - 1405-1560 1405-1560 - 1405-1560 1405-1560
m/sec m/sec - m/sec m/sec
Conductivity Resolution - - 0.01 mS/sec 0.017 mS/sec - 0.01 mS/sec
Conductivity Range - - 20-75 mS/cm 0-70 mS/sec - 20-75 mS/cm
System Depth Accuracy: 4.6 meters or 2% of depth, whichever is greater.
*Nominal accuracy characterization based on XCTD horizontal profiles against a
calibrated transfer CTD (each comparison used 4pt. smoothing). 95% of
tabulated data was within ±0.035° and mS/cm of the transfer CTD.
**External RF demodulator required.
SEA-AIR SYSTEMS DIVISION
7 Barnabas Road, Marion, MA 02738 TEL (508) 748 -1160 FAX (508) 748-3626 EMAIL sea_air@sippican.com www.sippican.com
