The EXO combination conductivity and temperature sensor should be installed in a sonde in nearly all sonde applications. Not only will this sensor provide the most accurate and fastest response temperature data, but it will also provide the best data for the use in temperature compensation for the other EXO probes. The conductivity data is used to calculate salinity, non-linear function (nLF) conductivity, specific conductance, and total dissolved solids, and compensate for changes in density of water (as a function of temperature and salinity) in depth calculations if a depth sensor is installed.
The temperature sensor
uses a highly stable and aged thermistor with extremely low-drift
characteristics. The thermistor’s resistance changes with temperature.
The measured resistance is then converted to temperature using an
algorithm. The temperature sensor receives a multi-point NIST traceable
wet calibration and the accuracy specification of 0.01˚C is valid for
expected life of the probe. No calibration or maintenance of the
temperature sensor is required, but accuracy checks can be conducted.
conductivity sensor uses four internal, pure-nickel electrodes to
measure solution conductance. Two of the electrodes are current driven,
and two are used to measure the voltage drop. The measured voltage drop
is then converted into a conductance value in milliSiemens (millimhos).
To convert this value to a conductivity value in milliSiemens per cm
(mS/cm), the conductance is multiplied by the cell constant that has
units of reciprocal cm (cm-1). The cell constant for the conductivity
cell is approximately 5.5/cm ±10%. For most applications, the cell
constant is automatically determined (or confirmed) with each deployment
of the system when the calibration procedure is followed.
sensors have internal thermistors for quality assurance purposes.
Turbidity uses the internal thermistor for temperature compensation,
while all other EXO sensors reference the C/T probe for temperature
compensation. To display and log temperature, a C/T probe must be
installed in an EXO sonde. Thermistor readings are logged in the sonde’s
raw data–viewable in KOR software–but are not included in data exported
EXO Conductivity & Temperature Smart Sensor
Desktop Software Compatible: Yes
Digital / Digital Sensors: Yes
Equipment used with: EXO1, EXO2
Measurement Method / Channels: 4-electrode nickel cell
Medium: Fresh, sea or polluted water
Operating Temperature: -5 to +50°C
Parameters Measured : Conductivity, Temperature, Salinity, Specific Conductance, TDS
Precision: 0 to 100: ±0.5% of reading or 0.001 mS/cm, w.i.g.; 100 to 200: ±1% of reading
Response Time: T63<2 sec
Storage Temperature: -20 to +80°C
Unit of Measure: microSiemens/centimeter
User Calibratable: Yes