Double Tipping Bucket Rain Gauge RS485 | NBL-W-DRS | NiuBoL

The NiuBoL NBL-W-DRS Double Tipping Bucket Rain Gauge is a rainfall measurement sensor designed for automatic weather stations, hydrological monitoring, agricultural meteorology, environmental research and remote rainfall data collection.

This RS485 rain gauge adopts a dual-stage tipping bucket mechanism with stainless steel tipping components and supports the Modbus RTU communication protocol. It offers selectable rainfall resolutions of 0.1 mm, 0.2 mm and 0.5 mm, allowing users to choose the appropriate configuration for different precipitation monitoring projects.

The instrument collects rainfall through a 200 mm diameter opening and uses a calibrated tipping mechanism to measure accumulated precipitation. Rainfall measurements can be read by compatible RS485 data loggers, PLC, RTU and weather station controllers.

With digital communication, low power consumption and an outdoor installation design, the NBL-W-DRS provides a practical rainfall monitoring solution for meteorological observation networks and automated environmental monitoring systems.

Key Features of the Double Tipping Bucket Rain Gauge

Dual Tipping Bucket Design    A two-stage tipping mechanism guides collected rainwater through the measuring system for rainfall counting.

Selectable Resolution    Available in 0.1 mm, 0.2 mm and 0.5 mm rainfall resolution versions to accommodate different observation requirements.

RS485 Modbus RTU    Supports digital data acquisition and integration with compatible industrial controllers and weather monitoring systems.

Stainless Steel Tipping Buckets    Streamlined stainless steel tipping components facilitate smooth water flow, cleaning and maintenance.

200 mm Rainfall Collector    A 200 mm diameter collection opening provides a defined collecting area for rainfall measurement.

Low Power Consumption    Operates from DC 4.5–30 V with a maximum power consumption of 0.24 W.

NBL-W-DRS Double Tipping Bucket Rain Gauge Technical Specifications

Note: The 0–4 mm/min specification represents the rated rainfall intensity measurement range. The maximum allowable rainfall intensity of 8 mm/min is not the rated measurement range. 

Rainfall Measurement Accuracy: ±0.4 mm for accumulated rainfall ≤10 mm; ±4% for accumulated rainfall >10 mm.

How Does a Double Tipping Bucket Rain Gauge Work?

A double tipping bucket rain gauge measures liquid precipitation by collecting rainfall and transferring it through a calibrated mechanical tipping system.

When rain enters the collection opening, the water flows through a funnel into the upper tipping bucket. The collected water then passes through an intermediate funnel and reaches the counting tipping bucket.

Once the counting bucket accumulates a calibrated quantity of water, it tips and activates a magnetic reed switch. The electronic circuit detects the tipping event and processes the corresponding rainfall measurement.

The dual-stage design helps regulate the transfer of water to the counting bucket. The streamlined stainless steel tipping components facilitate water drainage and simplify cleaning.

Different product configurations provide rainfall resolutions of 0.1 mm, 0.2 mm or 0.5 mm. The measured rainfall depth is transmitted through the RS485 Modbus RTU interface.

Unlike an analog pulse-only rain gauge, the RS485 version allows compatible data acquisition equipment to read rainfall measurements directly through Modbus communication.

RS485 Modbus RTU Communication

The NBL-W-DRS rainfall sensor uses the RS485 Modbus RTU protocol, enabling integration with industrial monitoring equipment, data loggers, remote terminal units and automatic weather stations.

Modbus Register Address

Example: Reading the Rainfall Value

The following Modbus RTU command reads the current rainfall register from device address 0x01.

Master Request:01 03 00 00 00 01 84 0A

Sensor Response:01 03 02 00 0A 38 43

The returned rainfall data is 0x000A, equivalent to decimal 10.

Because the Modbus register value is scaled by a factor of 10:

Actual Rainfall = 10 ÷ 10 = 1.0 mm

The reading represents rainfall depth in millimeters. To calculate rainfall intensity in mm/min or mm/h, the connected data acquisition system must determine the rainfall increment over a known measurement interval.

When calculating accumulated rainfall across multiple readings, the monitoring system should also account for clearing commands, device resets and any automatic reset behavior supported by the installed device.

RS485 Wiring Connection

Applications of the NBL-W-DRS Rainfall Sensor

The NBL-W-DRS RS485 double tipping bucket rain gauge can be integrated into different outdoor rainfall observation and environmental monitoring systems.

Automatic Weather StationsRainfall measurement for automatic weather monitoring systems, meteorological observation stations and weather data acquisition networks.

Agricultural MonitoringRainfall data collection for crop production, farmland monitoring, agricultural meteorology and irrigation management support.

Hydrological MonitoringPrecipitation observation for river basins, catchments, watersheds and hydrological monitoring projects.

Flood Monitoring SystemsRainfall data acquisition for integration into flood monitoring and early-warning information systems.

Reservoir and Water ManagementRainfall monitoring for reservoir catchments, water resource management and watershed observation.

Environmental ResearchPrecipitation measurement for environmental studies, field experiments, ecological observation and educational research projects.

Rain Gauge Installation Guidelines

Proper installation is important for obtaining reliable rainfall measurements from a tipping bucket rain gauge.

Installation Location

Install the rainfall sensor in an open location with minimal surrounding obstructions. According to the installation manual, objects higher than the collecting opening should be avoided within approximately 3–5 meters of the rain gauge.

Mounting Foundation

The installation manual recommends a concrete foundation approximately 400 × 400 mm, or a circular foundation with a diameter of approximately 400 mm. The foundation should be level and stable, with a minimum recommended foundation height of 300 mm.

The collecting opening should be installed approximately 700 mm above ground level, following the documented installation arrangement.

Level Adjustment

Secure the rain gauge to its mounting foundation and use the integrated circular level indicator to check alignment. Adjust the installation until the level bubble is centered.

The tipping bucket inclination has been calibrated and adjusted before delivery. Under normal installation conditions, users should not modify the factory-calibrated tipping bucket adjustment screws.

Commissioning Test

Important: Before using the instrument, remove the transport retaining band from the internal tipping mechanism.

Slowly introduce clean water into the funnel and observe whether the tipping buckets move freely. At the same time, verify that the connected RS485 data logger or monitoring controller receives the corresponding rainfall readings.

This test should be completed before leaving the installation site to identify potential mechanical or communication problems.

Maintenance and Cleaning

Routine maintenance helps reduce measurement errors caused by debris, contamination or mechanical obstruction.

The rainwater collecting opening, funnel and internal tipping buckets should be checked regularly, especially in outdoor environments with leaves, dust, insects or other debris.

Use clean water to rinse the tipping buckets when necessary. A soft brush may be used carefully to remove deposits. Avoid touching the inner tipping surfaces directly with fingers or hard objects, as contamination or mechanical damage may affect measurement accuracy.

For long-term outdoor operation, the manual recommends cleaning approximately once per month and carrying out a more thorough inspection at least every three months.

If rainfall is not being recorded correctly, inspect the water path, tipping mechanism, RS485 wiring, communication settings and connected data acquisition equipment before replacing the sensor.

Available Models and Rainfall Resolution Options

The NBL-W-DRS rain gauge family includes different configurations for rainfall resolution and tipping bucket construction.

The rainfall resolution is determined by the selected sensor model. Customers should confirm the required resolution, tipping bucket construction and communication configuration before ordering.

The NBL-W-DRS is a rainfall measurement sensor rather than a complete cloud monitoring station. For remote monitoring, it can be connected to a compatible data logger or communication gateway that provides the required data transmission functionality.

FAQ About the Double Tipping Bucket Rain Gauge

Q1. What is a double tipping bucket rain gauge?

A1. A double tipping bucket rain gauge is a precipitation measuring instrument that uses two tipping stages. Rainwater first enters an upper tipping mechanism before passing to a calibrated counting bucket. The counting mechanism produces rainfall measurements based on the quantity of collected water.

Q2. What is the difference between a single and double tipping bucket rain gauge?

A2. A conventional single tipping bucket rain gauge directly transfers incoming water to a counting bucket. A double tipping bucket design includes an additional upper tipping stage that regulates water transfer before the counting stage. Actual measurement performance depends on instrument design and calibration.

Q3. What rainfall resolutions are available for the NBL-W-DRS?

A3. The NBL-W-DRS is available with 0.1 mm, 0.2 mm and 0.5 mm rainfall resolution options. The required resolution should be specified when ordering.

Q4. Does the rain gauge support RS485 Modbus RTU?

A4. Yes. The NBL-W-DRS 485-type rain gauge supports RS485 communication using the Modbus RTU protocol. It can communicate with compatible PLCs, data loggers, RTU and automatic weather station controllers.

Q5. Can the rain gauge directly provide rainfall intensity in mm/min?

A5. The documented rainfall register provides rainfall depth in millimeters after scaling. Rainfall intensity can be calculated by the data collection system when the rainfall increment and measurement interval are known. Register clearing or reset events must be considered.

Q6. Can the NBL-W-DRS be used in an automatic weather station?

A6. Yes. The sensor can be integrated with compatible RS485 Modbus weather station data loggers and monitoring controllers to collect rainfall measurements as part of a meteorological monitoring system.

Q7. Does the rain gauge require an external power supply?

A7. Yes. The RS485 version requires a DC 4.5–30 V power supply. Its maximum power consumption is 0.24 W.

Q8. Can this rain gauge measure snowfall?

A8. The standard NBL-W-DRS is intended for liquid precipitation measurement. Snowfall, ice and freezing precipitation require a suitable measuring arrangement and should not be assumed to be accurately measurable by an unheated tipping bucket rain gauge.

Q9. How often should a double tipping bucket rain gauge be cleaned?

A9. Cleaning frequency depends on environmental conditions. The user manual recommends cleaning approximately once per month during long-term outdoor operation and performing a thorough inspection at least every three months.

Q10. What should be checked before the rain gauge is put into operation?

A10. Remove the transport retaining band, verify the installation level, introduce clean water to confirm normal tipping movement, and check that the monitoring equipment receives rainfall readings correctly.

Related Rainfall Monitoring Solutions

In addition to the NBL-W-DRS double tipping bucket rain gauge, NiuBoL provides rainfall measurement sensors and environmental monitoring equipment for agricultural, meteorological and hydrological applications.

Customers can explore other rain gauge sensors for different rainfall measurement requirements, or view the NBL-W-RS tipping bucket rain gauge for an alternative rainfall monitoring configuration.

For complete station integration, rainfall sensors can be combined with compatible weather data loggers, communication gateways and other meteorological instruments to create a rainfall and weather monitoring system.

Request a Quotation for the NBL-W-DRS RS485 Rain Gauge

Looking for a reliable double tipping bucket rain gauge manufacturer or supplier?

NiuBoL supplies rainfall sensors and environmental monitoring instruments for weather stations, agricultural monitoring, hydrology and industrial data acquisition projects.

For a quotation or technical consultation regarding the NBL-W-DRS double tipping bucket rain gauge, please provide your required rainfall resolution, output configuration, order quantity and destination country.

Our team can assist with model selection, technical documentation and integration requirements for your monitoring project.

NBL-W-DRS Double tipping bucket rain sensor Datasheet

NBL-W-DRS-Double-Tipping-Bucket-Rain-Sensor-Instruction-Manual.pdf