New generation CTD system [conductivity-temperature-depth sensor]

Author

Brown, Neil L.

Author_Institution

EG&G Ocean Products Inc., Cataumet, MA, USA

Volume

13

Issue

3

fYear

1988

fDate

7/1/1988 12:00:00 AM

Firstpage

129

Lastpage

134

Abstract

A microprocessor-based CTD (conductivity-temperature-depth) sensor unit is described in which the microprocessor is used to vary the analog-to-digital conversion process to achieve 16-bit resolution at a measurement rate of 500 measurements per second, or 18-bit resolution at 30 measurements per second. Software control of resolution, sampling rate, and sampling sequence permit the sensor unit to be software-configured for a wide variety of missions. Pressure and conductivity sensors are expected to substantially improve the system accuracy. The conductivity cell design has six electrodes which are all relatively remote from the external measurement volume (approximated by a 2-cm diameter sphere). This so called recessed-electrode concept is expected to eliminate calibration drift due to contamination of the electrodes and the insulating surfaces of the cell, thus ensuring excellent long-term stability

Keywords

analogue-digital conversion; computerised instrumentation; electric sensing devices; electrical conductivity measurement; microcomputer applications; oceanographic equipment; temperature measurement; 16-bit resolution; 18-bit resolution; analog-to-digital conversion process; calibration drift; conductivity cell; conductivity temperature depth sensor; long-term stability; recessed-electrode; Analog-digital conversion; Calibration; Conductivity measurement; Electrodes; Microprocessors; Pollution measurement; Sampling methods; Sensor phenomena and characterization; Sensor systems; Volume measurement;

fLanguage

English

Journal_Title

Oceanic Engineering, IEEE Journal of

Publisher

ieee

ISSN

0364-9059

Type

jour

DOI

10.1109/48.567

Filename

567