Remote Hydrologic Monitoring Sends Rainfall Intensity Data Online

Data Logger Transmits Hydrometric Data Via 4G Cellular Modem

hydrologic monitoringCAS DataLoggers provided the hydrologic monitoring solution for a meteorologist manning a weather station measuring local rainfall intensity over the summer. To get more accurate rainfall data for flood warnings and weather predictions, he needed an environmental data logger to connect to his tipping bucket rain gauges. Previously, he had been looking at a combination data logger and sensor, but that product lacked a way to remotely send data directly to his desktop. The solution had to be flexible enough to accommodate additional meteorological sensors if his needs changed in the future.

CAS supplied the rain gauge with two dataTaker DT90N data loggers as a low-cost remote hydrologic monitoring solution. The DT90N is a compact, rugged data logger, sealed to an IP67 rating for solid protection from the environment. Designed as a solution that can be quickly deployed, the system has standard inputs including a digital state/event counter plus an SDI-12 port and a Modbus RTU client for connection to intelligent sensors like the meteorologist’s weather stations. The digital counter inputs interface directly to the switch of the customer’s tipping bucket rain gauge sensor. A built-in 16Wh lithium battery allows the unit to record the rainfall once a minute and upload data once an hour using just a 2W solar panel year-round.


Currently, the DT90N data loggers are recording data at two remote rural sites where each device has been installed into a small protective polycarbonate enclosure for direct protection from the elements. Through the attached Texas Electronics TR-525I 6” rain gauge, the DT90N’s log the total amount of rainfall during the season to determine the local rainfall intensity in their area, given in inches per hour. For each 0.01” of precipitation, the bucket tips and momentarily closes a switch that increments the count in the data logger. Every minute, the logger records this count to calculate the current’s intensity and also update the accumulated rainfall for the day.

One key factor in the user’s decision to go with the DT90N was the serial sensor ports that could easily accommodate the addition of a weather station such as the Vaisala WXT530 using either the SDI-12 or Modbus RTU interface.

Each logger’s internal memory holds over 500,000 readings, overwriting the oldest data when the storage capacity is full. This secure non-volatile data storage prevents data from being lost if the power happens to fail. Data is uploaded once an hour using a 4G cellular modem using FTP to the dataTaker Live cloud service. This service provides easy to configure dashboards to display the intensity and accumulated rainfall along with long-term storage and the ability to download recorded data for local analysis. Using the programmable alarms built into the DT90N, the logger can transmit SMS messages during periods of very high rainfall and also change the transmission rate to provide faster update rates.

The loggers are supplied with free configuration software for both Windows. This software provides a user-friendly interface for configuring the sensor inputs, sample rates, setting the units, scaling the data, defining alarms, and setting the upload frequency and destination. Operators can download data stored in the logger, chart it, and export it in native or CSV format files.

The dataTaker DT90N dataloggers are ideal solutions in this hydrologic monitoring application since the meteorologist has access to all the rainfall data online. No one has to spend time driving out to the loggers for data collection or battery changes, which helps keep costs down. Additionally, the loggers’ automatic SMS alarms allow the meteorologist to keep on top of heavy rainfall events while the loggers themselves give reliable operation in the worst weather.

For more information on dataTaker DT90N Data Loggers, or to find the ideal solution for your application-specific needs, contact a CAS DataLogger Application Specialist at (800) 956-4437 or request more information.