Seametrics CT2X Logger X-Series Integration Guide

Real-Time Water Quality Measurements

The Seametrics CT2X Logger is a conductivity and temperature sensor with built-in data logging. The sensor is compatible with NexSens X-Series data loggers using the SDI-12 communication protocol and sensor interface. A pre-defined script on NexSens X-Series data loggers is able to detect, log, and transmit all parameters available on the sensor. Parameter data is transmitted, in real-time, at a user-specified interval (e.g., 10 minutes) to the NexSens WQData LIVE Web Datacenter. There, data is stored on customizable dashboards with statistics and graphical interfaces for each parameter. Users can download and send data reports via Email, FTP, or an API. Below is information on the settings and wiring required to integrate these sensors with a NexSens X-Series data logger.

Seametrics CT2X Conductivity Loggers product page.

Figure 1: Seametrics CT2X integration with NexSens X-Series data loggers for real-time water quality measurements.




Compatible Models

Seametrics provides CT2X models that are available to measure from 5 to 300 PSI, or~11.5 to 700 feet of water, respectively. The model of the sensor does not affect the wiring or integration outlined below.


Seametrics CT2X Conductivity and Temperature sensor product page

Figure 2: Seametrics CT2X Conductivity Logger




Sensor Integration

All default settings on the CT2X sensor will work with NexSens X-Series data loggers. Once the sensor is wired or connected properly, a pre-defined script on the data logger will automatically detect the sensor.

1. Wiring

In nearly all applications involving NexSens integration, a waterproof UW8 plug will be added to the sensor cable. However, in other applications, when the sensor cable requires protection, it may need a connection to a NexSens UW-FWP or an external junction box. Both options are vented, allowing for the sensor’s compensation for atmospheric pressure. The SDI-12 interface allows for an automatic barometric compensation in absolute units.

Figure 3: NexSens UW-FWP J-pin out

Figure 4: NexSens UW8/UW-FWP Plug pin out


NexSens UW8/
UW-FWP Plug Pin
UW-FWP J Pin*NexSens UW8-FLx Wire Color**Seametrics Wire ColorSignal

*NexSens UW-FWP Field Wireable Plug
**NexSens UW Plug to Flying Lead Cable


2. Automatic Sensor Detection

After wiring in the proper signal connections to an X-Series data logger, the sensor can be programmed onto the logger via automatic detection.

X-Series Logger Detection and Script Information

The X-Series data loggers include a pre-loaded CT2X script, which must be enabled before detection.

Configure Sensor Scripts

X2 Script NumberCommunication ProtocolBaud RatePower TypeWarmup Period (sec)Measurement Command


Script Parameters

The X-series script retrieves pressure and temperature data from the sensor. From these measurements, the logger then calculates the overall water level based on a known conversion factor.

Linear Conductivity*µS/cm
Non-linear Conductivity**µS/cm

*Linear conductivity is compensated by changes in temperature (2.1% per °C).
**Non-linear conductivity is utilized in natural waters, such as groundwater, streams, and rivers, that have very low conductivity. Conductivity in these natural waters typically does not respond to temperature in a linear fashion.


3. Setting up WQData LIVE

Once an X-Series data logger has finished a new sensor detection, it will automatically push the sensor configuration to the WQData LIVE web data center. Follow the three articles below to create a WQData LIVE account and a project/site. Then add the data logger to the project using the included claim code.



Real-Time System Application

Real-time water quality measurements from the Seametrics CT2X Loggers are useful in various environmental monitoring applications.

Applicable Systems

Discover applicable uses for the Seametrics CT2X Loggers.


Water Quality Measurements

Learn more about water quality measurements on the NexSens Blog Page.


Sensor Manual

For additional information on the Seametrics CT2X Logger, please refer to the Seametrics CT2X Logger Manual.