Onset S-RGB-M002 Specifications

Rain Gauge Smart Sensor (S-RGx-M002) Manual

The rain gauge smart sensor is designed to work with HOBO® stations. The smart sensor has a
plug-in modular connector that allows it to be added easily to a HOBO station. All sensor
parameters are stored inside the smart sensor, which automatically communicates
configuration information to the logger without the need for any programming or extensive
user setup.

Specifications

Rain Gauge Smart Sensor

Models: S-RGA-M002

S-RGB-M002

Items included:

• Two hose clamps

• Three screws

Accessories:

• Guy wire kit (M-GWA)

• 1.5 meter mast (M-MPB)

• Mast level (M-MLA)

Measurement Range 0 to 12.7 cm (0 to 5 in.) per hour, maximum 4000 tips per logging

Calibration Accuracy ±1.0% at up to 20 mm/hour (1 in./hour)

Resolution 0.01 in. (S-RGA-M002) or 0.2 mm (S-RGB-M002)

Calibration Requires annual calibration: can be field calibrated or returned to the

Operating Temperature Range 0° to 50°C (32° to 122°F), survival -40° to 75°C (-40° to 167°F)

Environmental Rating Weatherproof

Housing 15.24 cm (6 in.) aluminum collector and base

Mechanism Tipping bucket; stainless steel shaft with brass bearings

Dimensions 22.8 cm height x 15.4 cm diameter (9 x 6 in.), 15.4 cm (6.06 in.)

Weight 1 Kg (2 lbs)

Bits per Sample 12

Number of Data Channels* 1

Data Format Number of tips per recorded measurement, reported in inches or

Measurement Averaging No

Cable Length Available 2 m (6.6 ft)

Length of Smart Sensor
Network Cable*

* A single HOBO station can accommodate 15 data channels and up to 100 m (328 ft) of smart sensor cable (the digital

communications portion of the sensor cables).

interval

factory for re-calibration

receiving orifice

millimeters; S-RGA-M002 0.01 in. per tip, S-RGB-M002 0.2 mm per tip

0.5 m (1.6 ft)

The CE Marking identifies this product as complying with all relevant
directives in the European Union (EU).

WARNING: The black-anodized aluminum knife-edged ring is extremely sharp and can cause injury if

not handled properly. Do not press edge against any body parts as severe cuts and bleeding may occur.

14091-D MAN-SRGX

Rain Gauge Smart Sensor (S-RGx-M002) Manual

Mounting

NOTICE: During shipment the tipping assembly has been

secured to avoid possible damage to the pivot assembly. Lift off
the collector ring assembly (ring, screen, and funnel), and
remove the rubber band from inside to release the tipping­bucket mechanism before installation.

Cross arm

Mounting Considerations

• For the most accurate rainfall measurements, it is
recommended that you mount the Rainfall sensor upslope,
about 3 meters (10 feet) away from the tripod, on a 1.5
meter high mounting pole (M-MPB). Alternatively, you can
mount the Rainfall sensor on the tripod mast. This section
includes steps for both configurations.

• Tall objects can interfere with accurate rain measurements.
It is recommended that you place the rain bucket away
from the obstruction by a distance greater than three times
the height of the obstruction. If that is not possible, raise
the rain bucket as high as possible to avoid shedding.

• Avoid splashing and puddles. Be sure the gauge is high
enough above any surface that rain will not splash into the
top of the collector.

• Vibration can significantly degrade accuracy of the tipping
bucket mechanism. In windy locations make sure that the
bucket will be vibration-free. Consider using guy wires to
secure a pole or tower-mounted bucket.

• To provide long-term protection from moisture entry, the
smart sensor adapter must be mounted horizontally and
with the cable wires routed with drip loops so that water
drains away from the cable entry point as shown in the
example below. When mounted properly, the housing is
weatherproof (but not waterproof).

Smart
sensor
adapter
mounted
horizontally

Drip
loop

Hose clamps

Rain gauge sensor cable

Rain Gauge Sensor on the Tripod Mast

1. Open each hose clamp and place it around the mast.

2. Close the hose clamps until the rain gauge side bracket
easily slides into the clamp.

3. Hold the rain gauge sensor bracket against the mast with
the top of the rain gauge sensor above the top of the mast.

4. Slip the upper clamp over the side bracket and tighten the
clamp until the rain gauge is secure. Note: Be sure the
collector is above the top of the mast so you don’t get any
splashing, wind, shedding, or shadow effects.

5. Install the lower clamp and check that the top of the bucket
is level. Note: For windy locations, it is recommended that
you use the guy wire kit (M-GWA) to reduce vibration and
ensure data collection accuracy.

Mounting the Sensor on a Pole

Secure the rain gauge sensor to the separate mounting pole,
using the two hose clamps provided (see the instructions on
the next page). This separate mounting pole can either be
pounded in the ground or mounted in concrete, depending on
how firm the ground is.

In either case, be sure the pole is vertical when you install it.
The top of the pole should be slightly less than the height
desired for the top of the rain gauge sensor (1 meter or 3 feet is
typical).

Drip loop

• Refer to the Tripod Setup Guide for more information.

Mounting the Sensor on a HOBO Station Tripod

Secure the rain gauge sensor near the top of the mast on the

side opposite the cross arm, using the two hose clamps
provided.

Hose clamps

Rain gauge sensor cable

Rain Gauge Sensor on Separate Mounting Pole

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