• Temperature Sensor

Temperature Sensor

For water, soil, and air

  • Automatic minimum, maximum, and average calculations
  • Measurement range : -40° F to +140° F (-40° C to +60° C)
  • RS-485 and SDI-12 interfaces (auto-detecting)

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The Smart Temp is a high precision digital temperature sensor that meets USGS guidelines

It features the ability to automatically sample temperature and calculate minimum, maximum, and average temperatures on a flexible time scale.

This sensor is ideal for high-accuracy readings in water, soil, and air. It features fully-potted components, robust PVC Type II housing, and marine-grade stainless steel, making the sensor ideal for harsh environments. Model 51163 is small enough to easily deploy through standard 1” (2.5cm) PVC conduit with 8” (20.3cm) factory bend corners. It also offers a loop hole which can be used to mount weights or pull the sensor through pipes or other small areas.

SDI-12 output provides universal compatibility with any SDI-12- enabled data logger and low power applications, or use the standard SDI-12 command set over an RS-485 physical interface for applications that require long cable runs or many sensors.

  • Automatic minimum, maximum, and average calculations
  • RS-485 and SDI-12 interfaces (auto-detecting)
  • SDI-12 Ver 1.4 compliant
  • Firmware updates through RS-485
  • NIST certification available
  • High-accuracy temperature measurement
  • Extremely low current draw
  • Works in water, soil, or air
  • Suitable for freshwater or marine applications
  • Fully potted electronics
  • Tough PVC Type II housing
  • Celsius and Fahrenheit output
  • No calibration required


Silicon bandgap temperature sensor


SDI-12 v.1.4 and RS-485

Measurement range

-40° F to +140° F (-40° C to +60° C)


±0.18° F (±0.1° C) from 23° F to 122° F (-5° C to +50° C)
±0.2° C outside this range


0.01° C

Current draw

Idle: 10 μA (SDI-12), 0.6 mA (RS485)
Sample: 6mA for 10 ms
Transmit/receive: 6mA for ~ 100 ms (depends on length of data)
Peak: 30 mA for 1 ms during initial power-on


Celsius, Fahrenheit, and Kelvin


4.95” (125.7 mm) L x 0.7” (17.8 mm) ⌀ (#51126)
3.56” (90.4 mm) L x 0.70” (17.8 mm) ⌀ (#51163)