Solu-Blu Dissolved CO2 Probe X2 Integration Guide

The Pro-Oceanus Solu-Blu Dissolved COProbe measures dissolved CO2 in natural waters. The sensor is compatible with the X2 data logger using the RS-232 sensor interface. Below is information on the settings and wiring required for the integration of the Sol-Blu with an X2 data logger.

Pro-Oceanus Solu-Blu Dissolved CO2 Probe product page

Figure 1: Pro-Oceanus Solu-Blu Dissolved CO2 Probe


Configure Communication

The Solu-View software, typically included with the purchase of a Solu-Blue sensor, allows the user to adjust the sensor’s internal settings. The default baud rate (19200) and all other default settings allow for communication with the X2 data logger and should not be changed. The only setting that may be necessary to change is the salinity value if using in a saltwater environment.

  1. Wire in the sensor for RS232 communication and click Connect to sensor in the Solu-View software.
  2. Choose the 19200 baud rate and the correct COM port.
  3. A terminal window should open and the following output should appear:

Figure 2: Bootloader output in Solu-View software.


  1. Enter 3 on your keyboard to open the Setup sampling settings.
  2. Enter 3 on the keyboard once more and then enter the salinity value of the final deployment location.
    1. Values range from 0 to 50 psu and must be a whole number.

Figure 3: 35 PSU salinity value set on sensor.


  1. Once the value is entered, the sensor will return to the Setup sampling settings. Click the escape key and exit the software.
  2. The sensor is now ready for a detection on an X2 data logger. Follow the X2 data logger quick start guide or refer to the X2 Sensor Detection article for more information.


NexSens UW8 Connector Wiring & Pin Information

In the event of connecting a NexSens UW8 connector into an external device that is not an X2 data logger, below is the pinout of the NexSens UW8 connector, along with the signal associated with the communication, ground and power pins from the sensor.

Figure 4: NexSens UW8 plug pinout.


NexSens UW8 Pin NumberSignal
1RS-232 Tx
3RS-232 Rx


X2 Script Information

The X2 data logger includes a pre-loaded Solu-Blu script. Use the CONNECT software to enable the script for sensor detection.

Configure Sensor Scripts

X2 Script NumberCommunication ProtocolBaud RatePower TypeWarmup Period (sec)Frame


Script Parameters

The Pro-Oceanus Solu-Blu Dissolved COProbe utilizes Non-Dispersive Infrared Detection, the absorbance of light by specific molecules at particular infrared wavelengths, to determine the partial pressure of CO2 in natural waters. An internal air pump circulates the gases that cross the semi-permeable membrane, which are then exposed to an infrared light source at a specific wavelength. By comparing the absorption of this wavelength to a reference source, the partial pressure of CO2 within the solution can be measured and the following parameters are output.

CO2ppmvParts per million by volume of dissolved CO2 in solution.
CO2mg/LMass of CO2 per liter of solution.
Temperature°CWater temperature.*
Dissolved Gas PressurembarTotal gas pressure for all dissolved gases in solution.*

*Temperature and pressure from other gases can affect the performance of instruments measuring CO2. These factors are accounted for in the calibration of the sensors for long-term stability.