Rain Gauge—Texas Electronics TR‑525M

The Texas Electronics TR-525M tipping bucket rain gauge measures liquid precipitation and provides this data to the Sutron 9210B datalogger through a momentary potted reed switch. Here we describe how to use the TR-525M rain gauge in LI-COR eddy covariance systems with a biomet system running Biomet_100, Biomet_101, Biomet_102, and Biomet_103 programs. For more information and complete operating instructions, see: http://texaselectronics.com/products/rainfall/rain-gauge-tr-525m-metric.html

Precipitation Gauge TR-525M Specifications:
Resolution: 0.1 mm (0.004 in)
Accuracy: 1.0% up to 50 mm/hr (2 in/hr)
Collector diameter: 245 mm (9.66 in)
Operating Temperature Range: 0 to 50° C
Switch: Momentary potted reed
Switch Rating: 30 VDC @ 2A
Switch Closure Time: 135 ms

Installing the Rain Gauge

  1. Siting the Rain Gauge.
  2. Select a level location that is representative of the surrounding area.
  3. Mount the Rain Gauge.
    • Make sure the funnel is level and the body is plumb.
    • Be sure the tipping bucket can move freely from side to side and that it is not stuck in the center position.
    • If using a mast mount, be sure the mast is secure, stable, and plumb (vertical).
  4. Wire the Precipitation Gauge to the Datalogger.
  5. The TR-525M is supported by datalogger programs Biomet_100, Biomet_101, Biomet_102, and Biomet_103. For custom datalogger programs, use the Counter block and configure it as described in Rain Gauge (Texas Electronics TR-525M).
  6. Route cables through an opening in the bottom of the enclosure.Note: Route the sensor cable(s) through an opening in the enclosure prior to installing the leads in the terminal strip.

Lead Description Color Terminal
Shield Clear B1 (GND)
Signal Black B3 (I/O2)
Signal Return White B4 (GND)

Retrieving Data

If the system is configured to log biomet data in .ghg files for processing in EddyPro software or the SmartFlux System, data are stored on the removable USB storage device. Refer to the Biomet Instruction Manual for details.


  • Check the device regularly and keep the funnel and bucket clean and free of foreign materials such as dust, debris, and insects.
  • Check the field calibration periodically using the field calibration kit from Texas Electronics or using a home-made field calibration kit, as described in the manufacturer's instructions.