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 51163-300 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.

Model 51163-200 has a durable, marine-grade stainless steel tine for easy soil insertion.

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

Easily deployed through standard 1” PVC conduit with 8” factory bend corners

* Model # 51163-300

Technical Specifications

Sensor Silicon bandgap temperature sensor
Output SDI-12 v.1.4 and RS-485
Measurement range -40° F to +140° F (-40° C to +60° C)
Accuracy ±0.18° F (±0.1° C) from 23° F to 122° F (-5° C to +50° C)
±0.2° C outside this range
Resolution 0.01° C
Power requirement 9 to 18 VDC
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
Units Celsius, Fahrenheit, and Kelvin
Dimensions 4.95” (125.7 mm) L x 0.7” (17.8 mm) ⌀ (#51163-200)
3.56” (90.4 mm) L x 0.70” (17.8 mm) ⌀ (#51163-300)


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