LoRa Radio in Smart Agricultural Irrigation Systems

Smart agricultural irrigation requires real-time collection of soil moisture, temperature, and rainfall data, along with remote control of solenoid valves. Traditional wired solutions are costly to install and difficult to maintain, while the E91-DTU(xxxSL30) series LoRa radio offers an ideal wireless alternative.

System Architecture

The system consists of three parts:

Sensor End: Distributed monitoring points in the field, each with a soil moisture sensor and E91-DTU(400SL30) radio connected via RS485, using transparent transmission for real-time data reporting.

Relay Nodes: For areas beyond 8 km or with complex terrain, relay nodes are deployed using the relay function (AT+ROUTER=1). As described in the manual, the relay's ADDH and ADDL are set to the source and target network NETIDs respectively, enabling cross-network data forwarding.

Control Center: One E91-DTU(400SL30) serves as the master station, connected to an upper computer or SCADA system, aggregating data from all monitoring points and issuing control commands.

Key Configuration

All nodes share the same NETID (e.g., NETID=1) for same-network communication
Air rate set to 2.4 kbps (AT+RATE=0) for maximum range
Transmit power set to 30 dBm (AT+POWER=0) for full coverage
For battery-powered sensor nodes, enable WOR mode (AT+MODE=1) with a 2000 ms cycle to drastically reduce power consumption

Advantages

IP67 rating for long-term outdoor deployment
8–28 V wide voltage input, compatible with solar + battery solutions
Modbus protocol support for seamless integration with industrial sensors
Multi-level relay networking covering tens of square kilometers
Remote wireless configuration for maintenance-free operation