In-Situ AquaTroll X2 Integration Guide

The X2 data logger is compatible with the In-Situ Series of Multi-Parameter Water Quality Sondes (AquaTroll 200/400/500/600) using the RS-485 and SDI-12 sensor interfaces. An internal script (1004.lua) is utilized to detect and read measurements from the sensors automatically using RS-485. A generic script can be created in the CONNECT software to read sensor measurements using SDI-12. Below is information on the settings and wiring required to integrate these sensors with an X2 data logger.

In-Situ AquaTroll 600 Multi-Parameter Water Quality Sonde


Note: Ensure to review the sensor information and install sensor probes properly before deployment. Instructions can be found in the following manuals. 


Wiring for Software Communication

These sensors can be configured using the Win-Situ 5 software and communication device kit provided by In-Situ. If the sensor has a NexSens UW8 plug connection, a UW-FLxR can connect to the In-Situ communication kit following the wiring table below.

Communication Kit Color IndicatorSignalNexSens UW-FLxR Wire Color
BlueRS-485 A (+)Green
GreenRS-485 B (-)Blue


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 connecter, along with the signal associated with the communication, ground, and power pins from the sensor.

NexSens UW8 plug pinout.


NexSens UW8 Pin NumberSignal


Configure Communication for Modbus RS-485

  1. Connect the USB cable to a PC with the Win-Situ 5 software.
  2. Open the Win-Situ 5 software.
    1. Go to Preferences | Comm Settings to insert the correct COM port and address for the sensor for the initial connection.
    2. Brand new sensors should have address 1 and Even parity.
    3. Click the checkmark at the bottom once the proper changes are made.

Default communication settings for initial connection.


  1. Go to File | Connect to connect to the device.
  2. Travel to the tools icon once connected to the device and click on the Modbus Setup. Change the parity (and address if it interferes with other sensors) to None. 
    1. It is recommended to change the SDI-12 address to ensure there is no interference with other SDI-12 sensors.

Modbus settings setup.


Change parity to none.


  1. Now that the communication settings have changed, the software will disconnect from the sensor unless changes to the default settings are made.
    1. The sensor is now ready for detection on the X2 data logger.


X2 Script Information for Modbus RS-485

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

Configure Sensor Scripts

X2 Script NumberCommunication ProtocolBaud RatePower TypeWarmup Period (sec)Frame

Configure Communication for SDI-12

  1. Use information in the “Configure Communication for Modbus RS-485” section to connect to the sensor.
  2. Travel to the tools icon once connected to the device and click on the SDI-12 Setup.
  3. Choose desired parameters from the available list and ensure to document the order and units of each parameter.
    1. Ensure to change to a unique SDI-12 address if other SDI-12 sensors are connected to the data logger system.

In-Situ AquaTroll 500 SDI-12 parameter list.

  1. Use the CONNECT software to Generate a Generic SDI-12 Script following the parameter order and list set in the Win-Situ software.


AquaTroll Parameters

The AquaTroll 200 & 400 have the following pre-defined parameter lists for the internal 1004 script.

AquaTroll 200
ParameterDefault Unit
Specific ConductivityuS/cm
Salinityppt (parts per thousand)
Total dissolved solidsppt (g/L on WQData LIVE)


AquaTroll 400
ParameterDefault Unit
Dissolved Oxygenmg/L
Dissolved Oxygen%
Specific ConductivityµS/cm
Salinityppt (parts per thousand)
Total dissolved solidsppt (parts per thousand; g/L on WQData LIVE)


The parameters for the AquaTroll 500 and 600 sensors are dependent on the probes connected to the sonde. Below are the available probes and their corresponding parameters.

AquaTroll 500/600
ProbeParametersDefault Units
Specific ConductivityµS/cm
Salinityppt (parts per thousand)
Total Dissolved Solidsppt (parts per thousand)
Density of Waterg/cm3
Dissolved OxygenDissolved Oxygen Concentrationmg/L
Dissolved Oxygen Saturation% saturation
Total Suspended Solids*mg/L
Barometric PressureBarometric PressuremmHg
External VoltageV
Chlorophyll-aChlorophyll-a IntensityRFU
Chlorophyll-a Concentration**µg/L
Blue Green Algae – PhycocyaninBGA-PC IntensityRFU
BGA-PC Concentrationµg/L
Blue Green Algae – PhycoerythrinBGA-PE IntensityRFU
BGA-PE Concentrationµg/L
Nitrate ISENitrate Concentrationmg/L
Ammonium ISEAmmonium Concentrationmg/L
Chloride ISEChloride Concentrationmg/L

*Total Suspended Solids from Turbidity Tech Note
**Chlorophyll-a is programmed to report in RFU and can be configured to display Chl-a concentration; however, the user must first program in a conversion factor. To obtain the conversion factor, the user must obtain a grab sample of water at the deployment location and record the RFU reading from the sensor at the same time. Then, perform lab extraction of Chlorophyll-a (per APHA standard method 10200-H) to determine the µg/L. The laboratory obtained concentration in mg/L divided by the RFU reading of the same water will give the conversion factor. It is best to do this with several water samples from the same location and then average the conversion factors calculated to get better accuracy.