Multiparameter probe CTD 75M | Multiparametersonde

Medium Sized Multiparameter Probe

High accuracy probe for limnological and oceanographic measurements of physical,
chemical, and optical parameters

Main Features:

  • Depths: 500 m or 2000 m
  • Up to 8 Sensors
  • Microprocessor controlled
  • Online measurement or data storage in standard memory card at user programmable intervals 
  • Non-corrosive titanium housing
  • Internal battery or external power supply

Sea & Sun Technologies CTD75M offers excellent reliable performance in limnological, oceanographic, and off-shore areas. The probe is offered for two different applicable depths, 500 m and 2000 m. The CTD75M is a high accuracy probe that measures conductivity, temperature, and pressure as a standard configuration. Furthermore, it can be easily configured for a wide range of auxiliary sensors. More detailed information on the sensors can be found in the table below. Sea and Sun Technologies CTD75M records selected data at programmable time intervals whereas the data is stored in a non-volatile FLASH memory with a capacity of 128 Mbytes. A standard RS-232 connection is used for programming, data output, and data acquisition. Data is available as RS 232 signal and optional in online mode as digital FSK signal modulated on constant current.
A microprocessor controls the 16 bit analog to digital converters that have 8 channels. Therefore the probe can be equipped with     8 sensors. Additionally the CTD75M is equipped with an USB Port for fast data retrieval and configuration in laboratory. All calculations correspond to the current UNESCO formulas. A Standard Data Acquisition Software package “SSTSDA” compatible for Win” 95/98/Windows07©” provides probe configuration, probe service, data acquisition and offers visualization of data via graphs. An underwater bulkhead connector SUBCONN MCBH8M is used for communication (configuration and data retrieval) and external power supply. The power supply of the probe is activated by touching a reed contact with a magnetic rod. LED displays power supply status and optical control of memory access.

Recording Modes

Continuous mode:
All data sets are stored with the maximum possible data rate
Time mode:
Data sets are stored only at programmable intervals with several selectable schemes

Increment Mode:
Data sets are stored at programmable depth increments, up to 255 files can be stored without the need for data retrieval in between

Online Modes:
RS232C-on multiconductor cables
Optional: FSK-on single conductor cable (coaxial cable)


  • Housing: Titanium
  • Connector: Titanium, Neopren

Dimensions and Weights

  • L (housing) app. 385 mm
  • Ø (housing) 75 mm
  • L (overall) app. 654 mm
  • W (in air) app. 3.5 kg, including battery

Battery Endurance

The probe can be powered by internal batteries or DC-Power-supply (9 - 15 V) when using RS 232 output. Battery endurance varies widely depending on sensor configuration, temperature, cut-off voltage, and operating mode.

Continuous operating times (referred to 21 °C):

CTD75M with C, T, D, pH, ORP, DO*
CTD75M with turbidity meter
CTD75M with Cyclops-7

400 hours
300 hours
100 hours

DO* membrane covered model (Oxyguard, AMT).
Connection of further third party instruments and lower environmental temperature reduce operation time.


Standard sensor configuration is Conductivity, Temperature and Pressure. Further 5 channels can be equipped with different configurations.

Optional Sensors:
Turbidity, PH, Redox, Dissolved oxygen, Chlorophyll A

External Third Party Sensors:
PAR sensors, Transmissiometers, Fluorometers, Optical oxygen sensors

CTD75M offers flexibility by configuring the probe individually.

The CTD75M will be delivered in a compact, robust, and water resistant plastic case including cables, connection plugs, instruction manual, and a software CD.

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