Conductivity, Salinity and Temperature Data Logger

Small and cost-effective conductivity data logger. Easy to mount on moorings.
For use on subsea moorings, underwater equipment and water quality monitoring. Adding Star-Oddi’s protective housing offers flexible mounting of the conductivity meter.

Key Features

  • Smallest conductivity logger on the market
  • Flexible mounting with protective housing
  • Different ranges, high or low conductivity
  • High pressure tolerance
  • On/off saltwater switch for saving memory


Small and handy CT

The standalone conductivity data logger DST CT measures and records conductivity and temperature. Upon data conversion the software calculates and displays the salinity values and velocity with a time stamp. Size is only 46 mm length and 15 mm diameter.

Flexible mounting with protective housing

A plastic protective housing is available, recommended when fastening the data logger to subsea gear and moorings.


The DST CT self contained conductivity measuring device is used for a variety of studies including:

  • Oceanography and hydrography for long term stationary monitoring in coastal waters
  • Water quality monitoring with the low conductivity meter

High pressure tolerence

The conductivity recorder can be used in underwater environments from shallow water to deep sea.

SensorsConductivity (salinity) and temperature
Size (Diameter x Length)15mm x 50mm
Housing MaterialAlumina (Ceramic)
Weight (in Air/in Water)21g/13g
Data Resolution12 bits
Conductivity RangesChoose between: 13-63 mS/cm, 13-50 mS/cm, 3-37 mS/cm or 0.3 to 5 mS/cm
Conductivity ResolutionRange 13-63 mS/cm: 0.02 mS/cm, Range 13-50 mS/cm: 0.01 mS/cm, Range 3-37 mS/cm: 0.01 mS/cm, Range 0.3-5 mS/cm: 0.002 mS/cm
Conductivity AccuracyRange 13-63 mS/cm: +/-2 mS/cm, Range 13-50 mS/cm: +/-1.5 mS/cm, Range 3-37 mS/cm: +/-1.5 mS/cm, Range 0.3-5 mS/cm: +/-0.3 mS/cm
Salinity RangeDepends on conductivity and temp. range (consult with Star-Oddi)
Salinity Resolution*Range 13-63 mS/cm: 0.01 PSU, Range 13-50 mS/cm: 0.01 PSU, Range 3-37 mS/cm: 0.01 PSU, Range 0.3-5 mS/cm: 0.0005 PSU
Salinity Accuracy*Range 13-63 mS/cm: +/-1.5 PSU, Range 13-50 mS/cm: +/-1 PSU, Range 3-37 mS/cm: +/-1 PSU, Range 0.3-5 mS/cm: +/-0.1 PSU
Temperature Range-1°C to +40°C (30°F to 104°F)
Temperature Resolution0.032°C (0.058°F)
Temperature Accuracy+/-0.1°C (0.18°F)
Temperature Response TimeTime constant (63%) reached in 20 sec.
Pressure Tolerance2500m (please provide the depth you are going to use the logger at so the applicable membrane is applied)
Memory TypeNon-volatile EEPROM
Memory Capacity130,826 measurements per sensor
Memory MangementCustom programming
Sampling IntervalUser specified in second(s) minute(s), or hour(s)
Minimum Measuring Interval1 second
Multiple Intervals OptionUp to 7 different intervals
Data Retention25 years
ClockReal time clock. Accuracy +/-1 min/month.
CommunicationsCommunication Box, wirelss transmission when DST sits in the box. Connection to PC: USB cable.
Attachment Hole0.9 mm (diameter)
Battery Life4 years**
Replaceable BatteryNo

* Based on conductivity full scale accuracy at 24°C.
** For sampling interval of 10 minutes.
Warranty: 12 months.

Simple in Use, From Setup to Data Retrieval

The logger and the accompanying items are designed for ease of use throughout the research process, from setting up the logger, attaching it, to retrieving and analysing the data. The CT logger is supported by the SeaStar software and a Communication Box which have to be purchased with the first order.

Programming the Logger

To launch the CT conductivity probe for measuring it is placed into the Communication Box interface that connects with a USB cable to a PC computer. In the SeaStar software, the user sets the start time, start date and sampling interval before starting the recorder in measurement mode. The logger synchronizes its internal clock with the date & time on the computer being used.

Single or multiple intervals

There are two modes for sampling, either at a single interval throughout the period or multiple intervals. When choosing multiple intervals programming it is possible to define up to seven different intervals and number of measurements for each interval. Shifting between wide and narrow intervals can help in extending the measuring period due to memory limitation and have more frequent measurements during certain time periods.

Memory and Battery Life Calculations

The software automatically calculates when memory fills based on certain interval settings, making it easier for the user to decide how to program the tag. Estimation on battery consumption during that time period is also calculated.

Uploading the Data

After recovering the logger, it is inserted into the communication box and the recorded data is uploaded to the software. The results are displayed both in graphic and tabular form and the data can be exported to other programs. The time series data shows each measurement with its own time stamp.

Low energy consumption

After data retrieval the conductivity logger can be reused, as long as the batteries inside last. Battery life estimation is always reported upon connection with the logger. Due to the low energy consumption circuitry design the battery life is long, but actual lifetime depends on usage and sampling interval used.