The Ebyte E90-DTU (400SL30L) is an industrial-grade 30dBm LoRa wireless data transmission radio working at 410.125 to 493.125MHz with Semtech LoRa spread spectrum technology, delivering up to 10km long-range serial communication via RS485 and 3.3V TTL ports, supporting 8 to 28V DC or 4.2V lithium battery power with reverse constant current charging, Modbus slave polling, and 302uA low-power standby mode.
| Specification | DC Powered Mode (8-28V DC) | Battery Powered Mode (4.2V Lithium) |
|---|---|---|
| Model Name | E90-DTU (400SL30L) | |
| Carrier Frequency | 410.125 to 493.125 MHz (Default: 433.125 MHz, 84 Channels) | |
| Transmit Power | 30 dBm (Approx. 1W, 4 levels adjustable) | |
| Communication Distance | 10 km (in open line-of-sight environment) | |
| Serial Interfaces | Standard RS-485 / 3.3V TTL (Baud rate: 1200 to 9600 bps) | |
| Operating Voltage | DC 8V to 28V (DC jack or terminal block) | 4.2V Lithium Battery (Supports 120mA reverse constant charging) |
| Transmit Current | 288 mA @ 12V DC | 448 mA @ 4.2V DC |
| Standby Current | 11 mA @ 12V DC | 21 mA @ 4.2V DC |
| Low-Power Standby Current | 302 uA @ 12V DC (WOR period 4000ms) | 38 uA @ 4.2V DC (WOR period 4000ms) |
| Air Rate / Packet Size | 2.4 to 62.5 Kbps / Configurable 32, 64, 128, 240 Bytes | |
| Operating Modes | Transparent transmission, Modbus slave, Low power, Automatic acquisition | |
| Antenna Interface / Shell Size | SMA-K (External thread internal hole) / 84 x 82 x 25 mm (133g) | |
| Operating Temperature | -40 to +85 degrees C, 5% to 95% RH (non-condensing) | |
| tem | Description | |
| Operating Voltage |
DC 8～28V |
Support DC head and terminal power supply |
| Working current | DC powered |
Standby current consumption: 11mA @ 12V Transmit current consumption: 288mA @ 12V Low power standby current consumption: 302uA @ 12V Transmit power is instantaneous power, standby power is average power |
| Battery powered |
Standby current consumption: 21mA @ 4.2V |
|
| Communication Interface | TTL |
3.3V-TTL serial level communication interface |
| RS-485 |
Standard RS-485 communication interface |
|
| Frequency Range |
410.125~493.125MHz |
|
| Channel |
0～83, the default is 23, the channel interval is 1MHz |
|
| Airspeed |
2.4、4.8、9.6、19.2、38.4、62.5Kbps，default 2.4Kbps |
|
| Power regulation |
Support 4 gear transmission power configuration |
|
| Reverse charging |
120mA constant current charging, 4.2V preset charging voltage |
|
| Distance |
10Km |
|
| User configuration |
Host computer and Modbus RTU command |
|
| Operating mode |
Transparent transmission, Modbus slave, low power consumption, |
|
| Subcontracting mechanism |
Support configuration as 32, 64, 128, 240Byte, default 240Byte |
|
| Serial port baud |
1200、2400、4800、9600bps(default) |
|
| Data bits |
7, 8 (default 8) |
|
| stop bit |
1, 2 (default 1) |
|
| Check Digit |
NONE, ODD, EVEN (default NONE) |
|
| Antenna interface |
SMA-K, external thread internal hole |
|
| Product Size |
84mm*82mm*25mm (length*width*height) |
|
| Weight |
133 g ± 5g |
|
| Working temperature and humidity |
-40 ~ +85℃、5%~95%RH(non-condensing) |
|
| Storage temperature and humidity |
-40 ~ +105℃.5%~ 95%RH(non-condensing) |
|
Practical Application Scenarios
1. Remote Agricultural Solenoid Valve Control and Modbus Polling Network
In large-scale smart farm irrigation systems, controlling distant solenoid valves using wired RS485 infrastructure is cost-prohibitive due to cable length limitations and lightning risks. The E90-DTU (400SL30L) interfaces with field valve controllers via its RS485 port, functioning in Modbus slave polling or transparent transmission mode. Combined with an Ebyte central Modbus master gateway radio, it executes scheduled irrigation cycles across 10km remote zones without relying on cellular subscriptions or line-of-site wiring.
2. Off-Grid Solar-Powered Environmental Monitoring Telemetry
For remote meteorological stations and solar-powered soil monitoring nodes, power efficiency is critical. The E90-DTU (400SL30L) connects to environmental sensors via its 3.3V TTL or RS485 interfaces and runs on a 4.2V lithium battery with solar charge controller management. Utilizing Wake-On-Radio (WOR) mode, the DTU drops its standby current to 38uA at 4.2V, waking up periodically to transmit sensor telemetry before returning to sleep, ensuring uninterrupted year-round operational reliability.
3. Industrial Water Treatment and Pipeline Valve Telecontrol
In municipal water treatment plants and wastewater facilities, RS485 Modbus RTU field devices like flow meters, pressure transmitters, and motorized valves need to report back to a central PLC SCADA master. Operating within the 410.125 to 493.125MHz sub-GHz frequency range with 30dBm transmit power, the E90-DTU (400SL30L) penetrates reinforced concrete structures and metal obstacles, replacing long-distance field buses with robust wireless Modbus slave polling links.
FAQ Section
1. How does the Modbus slave polling and automatic acquisition feature work in the E90-DTU (400SL30L)?
The E90-DTU (400SL30L) natively supports Modbus RTU protocol parsing. In Modbus slave mode, the DTU can directly respond to Modbus query frames issued by a master PLC or SCADA system over the LoRa wireless link without requiring external protocol conversion modules. In automatic acquisition mode, the DTU actively polls local connected RS485 sensors according to pre-configured register addresses and timing intervals, packaging the collected data into wireless LoRa packets for automatic uplink transmission.
2. What power input options are available, and how does the reverse constant current charging feature function?
The DTU provides dual power input options: a wide voltage range of 8 to 28V DC via DC jack or screw terminal block, or a direct 4.2V single-cell lithium battery connection. When powered by an external 8 to 28V DC source while a 4.2V lithium battery is connected, the built-in charging circuit supplies a constant 120mA reverse charging current at a preset 4.2V cutoff to keep the battery charged, serving as an integrated uninterrupted power supply (UPS) for off-grid sites.
3. Can the E90-DTU (400SL30L) communicate with standard LoRaWAN gateways or standard LoRa serial modules?
The E90-DTU (400SL30L) uses Ebyte private LoRa spread spectrum physical layer modulation designed for point-to-point and point-to-multipoint transparent or Modbus communication. It is not compatible with standard LoRaWAN network server protocols (such as ChirpStack or The Things Network). However, it is fully compatible with Ebyte E90 series or E22 series modules operating on the same frequency (default 433.125MHz), air speed, and address encryption settings.
4. How can I optimize the air data rate and packet settings to minimize transmission latency over a 10km link?
To achieve maximum communication distance up to 10km, lower air data rates (such as 2.4Kbps) are recommended due to higher link budget margins. For applications requiring lower latency and faster throughput, the air data rate can be adjusted up to 62.5Kbps via host computer configuration or Modbus commands. Furthermore, packet sizing can be customized (32, 64, 128, or 240 bytes) to match specific Modbus RTU payload lengths, preventing unnecessary frame fragmentation and reducing serial latency.