YSI EXO1 Multi-Parameter Water Quality Sonde

The YSI EXO1 sonde includes four sensor ports (sensors sold separately) with internal data logging and battery power.


  • Titanium sensors with wet-mateable, universal sensor ports
  • Compact sonde fits in 2" diameter groundwater wells
  • Smart QC automatically checks for faults and errors to ensure successful deployments
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Modern and Efficient Design
The YSI EXO represents an advanced sonde platform that offers a wide range of capabilities to those dedicated to monitoring natural aquatic environments such as oceans, estuaries, rivers, lakes, and groundwater. The EXO1 sonde includes four sensor ports (sensors sold separately) with internal data logging and battery power.

Multi-Port Water Quality Sonde

  • Temperature
  • Conductivity
  • Depth
  • Dissolved oxygen
  • pH
  • ORP
  • Total algae (phycocyanin or phycoerythrin along with chlorophyll)
  • Turbidity
  • Fluorescent dissolved organic matter (fDOM)
  • Rhodamine WT
  • UV nitrate
  • ISE ammonium
  • ISE nitrate
  • ISE chloride

Outputs Four Calculated Parameters.

  • Salinity
  • Specific conductance
  • Total dissolved solids (TDS)
  • Total suspended solids (TSS)

Onboard Signal Processing and Memory
All EXO sensors are digital sensors with on-board signal processing and memory. Built-in sensor diagnostic and calibration data allow users to calibrate multiple sensors in one sonde and distribute to various other sondes in the field. Wet-mateable connectors allow for swaps in wet conditions, while active port monitoring automatically detects each sensor and verifies operation.

EXO1 Specifications
Diameter: 4.70cm (1.85 in)
Length: 64.77cm (25.50 in)
Peripheral Ports: 1 power communication port
Sensor Ports: 4
3-Year Warranty: Sonde; handheld
2-Year Warranty: Cables; conductivity/temperature and optical sensors; electronics base for pH, pH/ORP, ammonium, chloride, and nitrate sensors
1-Year Warranty: Optical DO cap and replaceable reagent modules for pH and pH/ORP sensors
3-Month Warranty: Replaceable reagent modules for ammonium, chloride, and nitrate sensors
Weight: 1.42kg (3.15 lbs)

General Sonde Specifications
Battery Life: 90 days**
Computer Interface: YSIP via USB Signal Output Adapter (SOA) and Bluetooth
Output Options: RS-232 & SDI-12 via DCP-SOA; Modbus & RS-485 via Modbus-SOA
Data Memory: 512 MB total memory; >1,000,000 Logged readings
Depth Rating: 0 to 250m (0 to 820 ft)
Sample Rate: Up to 4 Hz
Operating Temperature: -5 to +50°C (23 to 122°F)
Storage Temperature: -20 to +80°C (-4 to 176°F)

**Typically 90 days at 20˚C at 15-minute logging interval; temperature/conductivity, pH/ORP, DO, and turbidity sensors installed on EXO1; or temperature/conductivity, pH/ORP, DO, total algae, and turbidity sensors installed with central wiper that rotates once per logging interval on EXO2. Battery life is heavily dependent on sensor configuration.

  • (1) EXO1 sonde
  • (1) Probe guard
  • (1) Calibration cup
  • (1) Tool kit
  • (2) Port plugs
  • (2) D-cell alkaline batteries
  • (1) USB drive loaded with manual & KOR Software
Questions & Answers
Can the sonde be used in both fresh and salt water applications?
Yes, the sonde is rated for salt water applications with the exception of the ammonium, nitrate, and chloride sensors that are freshwater only.
How often do the sensors need calibrated?
This is highly dependent on the deployment location, but re-calibration intervals typical range from 2 to 8 weeks.
Are the EXO Series sondes compatible with 6-Series sensors?
No, only EXO sensors can be used with EXO sondes.
Can EXO1/2 sondes communicate via SDI-12?
EXO1 and EXO2 sondes support SDI-12 communication through the use of the DCP adapter. EXO3 sondes have built-in SDI-12 support, so the DCP adapter is not necessary with EXO3.
If I have multiple field sites and want to add turbidity sensors, do I have recalibrate all of my EXO sondes?
No, each sensor has it's own internal memory for storing calibration. All of your turbidity sensors can be calibrated with a single EXO sonde and then transferred to the field sites.
How is my EXO1 powered?
The EXO1 is powered with (2) D-cell batteries.
I'm worried about corrosion during a long-term deployment, what can I do?
A zinc anode kit (part number #599595) can be purchased to minimize corrosion. This anode kit is composed of zinc making it more susceptible to corrosion (oxidation) than the rest of the sonde. This kit is installed in an empty sensor port and prevents the rest of the sonde from corroding.
If I am using all of my sensor ports, can I still prevent corrosion?
Another way to prevent corrosion is to install an anode guard and guard weight (part number # 599563 and #599520) This guard and guard weight is composed of zinc and will protect the sonde from corrosion during a long-term deployment.
Can this sonde be powered by the EXO Handheld Display?
Yes, the EXO Handheld Display can power any of the EXO sondes for up to 20 hours on a single charge.
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