Onset RX3000 Technical Note

Remote Water Level Monitoring Technical Note

Product: HOBO® RX3000 Station

Summary: This technical note provides details on configuring the HOBO RX3000 Remote Monitoring Station with water

level sensors with a 4-20mA output.

The combination of the RX3000 station and one or more third-party water level sensors with 4-20mA analog outputs
provide a solution to remotely monitor water levels and access data via the internet. This system can also send notifications
when critical levels are reached. Typical applications include monitoring wells, groundwater, surface water, storm water
and storm surges.

Connecting the Water Level Sensor

Before connecting your water level sensor to the RX3000 station, make sure that the cable has been routed through
openings as needed. Specifically, if the cable needs to go through a well cap, do that before connecting the wires. Also
make sure that the cable is coming through one of the cable openings in the bottom of the RX3000.

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Remote Water Level Monitoring Technical Note

Connecting a Water Level Sensor that Can Operate from 12V Power

Connect as shown below.

Configuration with Sensors that work with a 12V Power Supply

Connecting a Sensor that Requires More than 12 Volts

Some water level sensors need excitation power higher than the 12 volts the RX3000 provides. The diagram below shows
how to use a 9V battery to boost the 12V excitation of the RX3000. This configuration requires a 9V battery connector such
as Radio Shack Model 270-325, and a diode rated for at least 50mA and 20V, such as a 4148 diode or a 5817 Schottky diode.
With a 1 minute logging rate and 30ms warm-up time, a good 9V battery should last for over a year in this configuration.
Onset recommends replacing the battery annually to be safe.

Analog Sensor Module Connections using a 9V Battery to Boost the Output Voltage

Connecting Desiccant Cartridge and Weatherproof Cable Channels

The desiccant cartridge should be located inside a vented, weatherproof enclosure (supplied by others). Install the
weatherproof cable channels in both channel openings in the bottom of the logger.

1-800-LOGGERS 2 www.onsetcomp.com