Van Essen Instruments CTD-Diver

Pressure transducer with integrated logger

Part # 51144

ctd diver

Frequent monitoring of soil and groundwater quality is traditionally a labor-intensive job. This is also the case if saltwater intrusion or contamination at remediation sites needs to be monitored.

The Van Essen CTD-Diver sets the standard for reliability and longevity in groundwater monitoring. The CTD-Diver is a fully stand-alone sensor with built-in data logger and battery. The compact ceramic casing and sensor and unparalleled conductivity measuring range (0-120 mS/cm) make the CTD-Diver suitable for use at every measuring site.

The CTD-Diver is impervious to the most aggressive substances found in water environments. Its ceramic casing resists when even the strongest metals yield.

CTD-Diver is a highly reliable compact probe for the simultaneous measuring of groundwater level, temperature, and conductivity. Measured values are stored in the probe's non-volatile internal memory.

In addition to internal data storage, the CTD-Driver can be connected to an external data logger, such as the Stevens DataLogic 3000, or data telemetry systems with the Diver-DCX SDI-12 output adapter, allowing the Diver to be used for real-time data monitoring applications.

Manual data download in the field from a Diver's internal storage can be done by utilizing the optional USB Interface Cable and connecting the diver directly to a desktop or laptop PC.

Shop Online

Related products

What's the Easiest and Quickest Way to Start Collecting Data and Access it Anywhere?

The Answer's in the Cloud.

eTracker is a cellular modem and "virtual" cloud-based data logger in one (meaning you don't need to install a separate data logger). Simply connect your sensor and a power source to eTracker and you're done. Configure (or reconfigure) anytime from any Internet-connected device, and use Stevens-Connect to retrieve your data, or forward it to your favorite software system.

Technical Specifications


Internal Battery, 10-year life with "typical" use

  • 5 million measurements
  • 2,000 readout cycles
  • 2,000 programming cycles

Sample interval

1 second to 99 hours

Data output options

  • SDI-12 when connected to Diver-DCX converter box
  • Manual data download using USB interface cable connected to computer
  • Manual data download using "Diver Mate" or "Diver USB Reading Unit" accessories

Conductivity Measurement

Range: 10 µS/cm to 120 mS/cm
Accuracy: ± 1.0% of reading
Resolution: ± 0.1% of reading

Operating temperature, compensated

32 °F to 122 °F (0 °C to 50 °C)

Temperature accuracy

± 0.18 °F

Temperature resolution

0.018 °F

Wetted parts materials

Housing: ceramic (ZrO2)
Conductivity sensor: platinum electrodes on ceramic (AI2 O3) carrier
O-rings: Viton®
Pressure sensor: ceramic (AI2O3)
Cap / nose cone: Nylon PA6 30% glass fiber

Physical size

5.31 in x Ø0.86 in (135 mm x Ø22 mm) including suspension eye


3.5 oz (100 grams)

Depth Range Typical Accuracy Long-Term Stability Resolution
33 ft (10 m) ±0.05% FS ±0.2% FS 0.07 in (0.2 cm)
164 ft (50 m) ±0.05% FS ±0.2% FS 0.39 in (1 cm)
328 ft (100 m) ±0.05% FS ±0.2% FS 0.78 in (2 cm)