TandD TR-51i

  • Measurement Range: -40°C to 80°C
  • Water Resistance: IP67 (Immersion Proof)
  • Internal Temperature Sensor: Thermistor
  • Logging Capacity: Up to 16,000 Readings
  • Low energy consumption for long battery life
  • Downloading Data: Infrared Communication / Optical Communication
  • Warning Monitoring Function
  • Compact Waterproof Type



The compact TR-51i Infrared Temperature Data Logger is designed to measure and record temperature. It is water resistant and can be used in an environment of -40°C to 80°C. It is equipped with a Warning Monitoring Function, an Adjustment Function, and an Infrared Communication Function. Battery powered operation allows the unit to be placed anywhere without the need for AC power.

Recorded data can be transferred to a PC separately via the TR-57DCi Data Collector or the TR-50U2 Communication Port. From there data can be analyzed or viewed in graph form.

The internal temperature sensor offers superior waterproof capacity and moderate response time, making the TR-51i suitable for use in transportation and storage, as well as in harsh environments.


Measurement Channels Temperature 1ch (Internal)
Sensor Thermistor
Measurement Units °C, °F
Measurement Range -40 to 80°C
Responsiveness Thermal Time Constant: Approx. 15 min.
Response Time (90%): Approx. 35 min.
Accuracy Avg. ±0.5°C
Measurement Resolution 0.1°C
Logging Capacity 16,000 readings
Recording Interval Select from 15 choices: 1, 2, 5, 10, 15, 20, 30 sec. or 1, 2, 5, 10, 15, 20, 30, 60 min.
Recording Mode Endless (Overwrite oldest data when capacity is full)
or One Time (Stop recording when capacity is full)
LCD Display Items Measurements, Recording Status, Battery Life Warning, etc.
Communication Interfaces Optical Communication (proprietary protocol)
Infrared Communication (IrPHY 1.2 low power)
Power(*1) Lithium Battery (LS14250) x 1
Battery Life(*2) Approx. 4 years (2 years with Infrared Communication Enabled)
Dimensions H 62 mm x W 47 mm x D 19 mm (excluding protrusions and sensor)
Weight Approx. 54 g
(including battery)
Operating Environment Temperature: -40 to 80°C
Waterproof Capacity IP67: Immersion proof
Lithium Battery (LS14250), Strap, User’s Manual (Warranty Included)
Data Collection Devices Communication Port: TR-50U2, TR-50U
Data Collector: TR-57DCi, TR-57U, RTR-57U
(*1) The included lithium battery (LS14250) is not sold in stores. Please purchase the optional battery set (TR-11P2) for replacement.
(*2) Battery life depends upon the measuring environment, recording interval, and quality of the battery being used. When infrared communication function is enabled, battery life may be further shortened if the unit is used under the inverter type fluorescent lighting.
(*3) This is the waterproof capacity of the data logger with the sensor connected.


The software included with the TR-5i series data loggers makes it possible to create detailed recording settings. Set the interval at which you want recording to occur and the timing at which you want the recording to start. When monitoring measurements for warnings the LED on the logger will flash and the time of the warning will be recorded.

Graphing software from TandD

The included graph application allows easy analysis of the recorded data. All data can be viewed in one graph window, regardless of the data format or from what type of device the data came from. Search and filter to get only the data you need. Data can be output as a text format file (CSV).