The Ebyte E90-DTU(400SL22) is an industrial SX1268-based 433MHz LoRa wireless data transceiver DTU featuring dual RS232 and RS485 serial ports, 22dBm transmit power, and up to 5km transmission distance. Supporting wide 8V-28V DC power input, automatic relay networking, LBT carrier sense, and RSSI signal reporting, it provides reliable Modbus RTU telemetry in harsh environments.
| Parameter | Specification | Remark |
|---|---|---|
| Model Number | E90-DTU(400SL22) | Industrial Wireless Data Radio DTU |
| Core RF Chipset | Semtech SX1268 | New generation LoRa spread spectrum engine |
| Working Frequency | 410.125 - 493.125 MHz | Default 433MHz Sub-1GHz ISM band |
| Transmitting Power | 22 dBm (approx. 160mW) | Multi-level adjustable via AT software |
| Transmission Distance | 5 km | Clear line-of-sight with external antenna |
| Communication Ports | RS232 and RS485 (2 Ports) | Industrial terminal block + DB9 design |
| Supply Voltage | 8V - 28V DC | Supports standard 12V/24V industrial rails |
| Special Functions | Automatic Relay, LBT, RSSI | Listen Before Talk & signal level readout |
| Antenna Interface | SMA-K (50 ohm) | External female thread internal hole connector |
| Net Weight | 128g | Rugged metallic enclosure |
Practical Application Scenarios
1. Long-Range Modbus RTU Telemetry for Water Treatment Plants
In municipal wastewater treatment facilities, field sensors and PLCs (such as Siemens S7-1200 or Schneider Modicon) are scattered across large physical footprints with heavy concrete barriers. The E90-DTU(400SL22) connects to the PLC via its RS485 terminal interface, converting standard Modbus RTU serial packets into 433MHz LoRa spread-spectrum signals. Operating at 22dBm transmit power, it maintains uninterrupted 5km telemetry links back to the SCADA control center without requiring expensive industrial Ethernet cable installation.
2. Multi-Hop Wireless Extension using Automatic Relay for Underground Mining
Mining and subterranean tunneling projects suffer from severe line-of-sight signal blockage around rock bends. By enabling the Automatic Relay feature on intermediate E90-DTU(400SL22) nodes, field engineers can create a multi-level ad-hoc wireless bridge. Data packets from RS232 environmental gas detectors or structural strain gauges automatically hop across intermediate relay DTUs back to the surface monitoring station, extending overall network reach far beyond standard single-hop limitations.
3. Collision-Free Power Distribution Telemetry with Listen-Before-Talk (LBT)
In smart grid distribution sub-stations where dozens of wireless telemetry units transmit periodically on the 433MHz frequency, packet collisions often lead to data loss. The E90-DTU(400SL22) utilizes Listen Before Talk (LBT) carrier sense technology. Before initiating a radio transmission, the DTU actively scans the RF channel; if ambient noise or active transmission is detected, it pauses transmission until the channel is clear, guaranteeing high packet delivery rates for critical electrical grid monitoring.
FAQ Section
1. How does the Automatic Relay function operate on the E90-DTU(400SL22)?
The Automatic Relay feature allows two DTU nodes to communicate over ultra-long distances by using one or more intermediate E90-DTU(400SL22) units as repeater stations. The relay requires no complex software routing table configuration—simply set the destination address, channel, and relay mode in the Ebyte setup utility, and the DTU automatically forwards incoming packet data across the 433MHz network.
2. Can both RS232 and RS485 serial ports be used simultaneously on the E90-DTU(400SL22)?
The E90-DTU(400SL22) features two physical ports (RS232 DB9 and RS485 terminal blocks), but they operate in a single-active serial bus arrangement. While both physical interfaces can remain physically connected to separate host devices or sensors, serial data should be sent sequentially to prevent data corruption on the internal UART bus.
3. How does the RSSI feature help during field deployment and antenna alignment?
The RSSI (Received Signal Strength Indicator) feature outputs actual signal power values (in dBm) alongside incoming data frames or via command query. Field engineers can read these values in real-time on a laptop or PLC to accurately adjust external SMA antenna alignment, evaluate multi-path interference, and ensure sufficient link margin across the 5km wireless connection.
