II. Recommended Test Equipment
IV. BASS Transducer and Cable Check
Appendix A. Other Signals of Interest
Appendix B. Suggested Form for
Appendix C. A Tattletale 4 BASS
Appendix D. MATLAB Script File
for BASS Calibration
The following is a series of test and calibration
procedures for the Oceanographic Instrument Systems
(OIS) Benthic Acoustic Stress Sensor (BASS). Although
these procedures were written for a BASS system with
a Tattletale 4 microcomputer, they should generally
apply to those BASS systems with Tattletale Model 5
Please send any comments or corrections to Marinna
Martini at the U.S. Geological Survey, or to the address
on the cover of this report.
CCW counter clockwise
DT-V differential time-voltage (circuit board)
ma, mA milliamps
mv, mV millivolts
p-p peak to peak
V, v volts
VDC volts, direct current
The procedures described here are presented so that
a technician with limited experience with BASS can perform
basic tests which, when executed properly, should be
a thorough evaluation of the health of the system. This
is not intended as an in depth explanation of how BASS
works. Should any significant problems be found, it
is suggested that you contact the manufacturer, Oceanographic
Instrument Systems, North Falmouth, MA. The Tattletale
controller is manufactured by the Onset Computer Corporation,
The following equipment was used to perform the electronics
evaluations described in this report. Models used at
USGS test facility are given as examples other equipment
with the same specifications may be substituted: 1.
Hewlett Packard Model 54601A 100MHz Oscilloscope: Featuring
four channel inputs, delay time and memory for trace
storage and recall. This scope does not have a separate,
external trigger input. 2. Tektronix Model 7613 Oscilloscope:
Featuring two channel inputs, delay time, store and
external trigger input. 3. BASS sensor pod, submerged
in water 4. Extender board 5. 21 VDC, 1.5 amp Power
supply 6. Computer with one RS232 serial port free 7.
Onset's TattleTools or other terminal emulation software.
8. BASS Schematics 9. Data Precision Model 3500 4 1/2
digit volt-ohmmeter 10. Onset TC-4 RS232 communications
cable 11. Tektronix AM503 Current Probe amplifier with
model P6302 probe 12. Oceanographic Instrumentation
Systems (OIS) nanosecond delay test unit 13. Capacitance
The author has used a number of terminal emulation
software packages to communicate with Tattletales rather
than the TattleTools software provided by Onset. These
procedures, therefore, have been written for use with
any terminal emulation software.
Use of trade names is for the purposes of identification
only and does not constitute any endorsement by the
Each sensor pod which makes a three axis current measurement
uses a total of eight acoustic transducers to do so.
These are generally rugged parts, however their capacitance
should be checked periodically and whenever there is
any suspicion of damage. To insure that no moisture
can penetrate the sealed housing, capacitance should
be measured after the transducer has been soaked in
water for several days. The capacitance is typically
1000 pf +/- 30 %. Note that the true capacitance will
be the capacitance measured with the test leads connected
to the transducer minus the capacitance of the test
leads by themselves.
The electrical condition of the cables can also be
checked by measuring capacitance. Once the capacitance
for each transducer has been recorded, the measurement
is repeated through the cable. A cable in good condition
should not significantly differ from the capacitance
reading at the transducer.
1. Morrison III, A.T., Williams 3rd, A.J., and Martini,
M., 1993, Calibration of the BASS Acoustic Current Meter
with Carrageenan Agar: Institute of Electrical and Electronics
Engineers, Oceanic Engineering Society, OCEANS '93 Conference
Proceedings, vol. 3, pp. 143-148.
2. Trivett, D.A., Terray, E.A. and Williams 3rd, A.J.,
Error Analysis of an Acoustic Current Meter, J. of Oceanic
Engineering, vol. 16, pp. 329-337.
3. Williams 3rd, A.J., 1984, An Acoustic Current Meter
Array for Benthic Flow-Field Measurements, Marine Geology,
vol. 66, pp. 345-355.