Dragino - RS485-LN
The RS485-LN is a versatile RS485-to-LoRaWAN bridge designed for industrial and environmental sensor networks. It allows to connect and monitor up to 15 Modbus RS485 sensors over long-range LoRaWAN wireless links. The device can be configured via the Dragino RS485 Configure Tool. There is as well a function to listen only to a modbus network and send the listened data over LoRaWAN. —
Table of contents
Specifications
- Indoor device
- Price ca. CHF 55.- (09.07.2025)
- LoRaWAN Class A & Class C
- Max 15 RS485 slave Modbus queries per uplink
- In Modbus mode…
- it is only possible to fetch data from a single device.
- the device can operate as master and slave (listening for incoming telegrams is supported)
- RS485 interface, Modbus RTU supported
- Power Supply: 7~24V DC
- Power Consumption: Idle 32 mA @12V, TX 65 mA @12V
- Dimensions: 135 x 70 x 30 mm
- Weight: 105 g (device only)
- Default Serial: 9600 baud
- Includes antenna and programming cable
Documents & Downloads
Ordering Info
- Part Number: RS485-LN
- Ordering Link
TTL-USB Serial Programming
To configure the RS485-LN with AT commands or the RS485 Tool, connect it via the 3.5mm programming jack using the included programming cable and a USB-TTL adapter.
Wire colors:
| Cable Color | Signal | Connects to USB-TTL |
|---|---|---|
| Black | GND | GND |
| Red | RXD | TXD (on adapter) |
| White | TXD | RXD (on adapter) |
Steps:
- Download and start the RS485 Configure Tool.
- Wire the USB-TTL adapter with the device cables and plug it into the computer.
- Plug the programming cable into the RS485-LN’s 3.5mm “PROG” jack.
- Power the RS485-LN via the screw terminal (7-24V DC).
- Start the RS485 Configure Tool and connect to the device
- Load the AT Command text file into the tool and Write the parameters.
- Add the device to a ttn application, add the payload decoder from below and restart the device.
Example: If you have 5 Modbus devices (addresses 3,4,5,6,7), each with 3 registers (Temp on 0, Humidity on 1, CO2 on 5, all 16-bit signed), use these AT commands for direct serial configuration, or enter them in the RS485 Configure Tool:
| Device | Sensor | Modbus Addr | Register | AT+COMMAND | AT+DATACUT |
|---|---|---|---|---|---|
| 3 | Temp | 3 | 0 | AT+COMMAND1=03 03 00 00 00 01,1 | AT+DATACUT1=7,1,4+5 |
| 3 | Humidity | 3 | 1 | AT+COMMAND2=03 03 00 01 00 01,1 | AT+DATACUT2=7,1,4+5 |
| 3 | CO2 | 3 | 5 | AT+COMMAND3=03 03 00 05 00 01,1 | AT+DATACUT3=7,1,4+5 |
| 4 | Temp | 4 | 0 | AT+COMMAND4=04 03 00 00 00 01,1 | AT+DATACUT4=7,1,4+5 |
| 4 | Humidity | 4 | 1 | AT+COMMAND5=04 03 00 01 00 01,1 | AT+DATACUT5=7,1,4+5 |
| 4 | CO2 | 4 | 5 | AT+COMMAND6=04 03 00 05 00 01,1 | AT+DATACUT6=7,1,4+5 |
| 5 | Temp | 5 | 0 | AT+COMMAND7=05 03 00 00 00 01,1 | AT+DATACUT7=7,1,4+5 |
| 5 | Humidity | 5 | 1 | AT+COMMAND8=05 03 00 01 00 01,1 | AT+DATACUT8=7,1,4+5 |
| 5 | CO2 | 5 | 5 | AT+COMMAND9=05 03 00 05 00 01,1 | AT+DATACUT9=7,1,4+5 |
| 6 | Temp | 6 | 0 | AT+COMMAND10=06 03 00 00 00 01,1 | AT+DATACUT10=7,1,4+5 |
| 6 | Humidity | 6 | 1 | AT+COMMAND11=06 03 00 01 00 01,1 | AT+DATACUT11=7,1,4+5 |
| 6 | CO2 | 6 | 5 | AT+COMMAND12=06 03 00 05 00 01,1 | AT+DATACUT12=7,1,4+5 |
| 7 | Temp | 7 | 0 | AT+COMMAND13=07 03 00 00 00 01,1 | AT+DATACUT13=7,1,4+5 |
| 7 | Humidity | 7 | 1 | AT+COMMAND14=07 03 00 01 00 01,1 | AT+DATACUT14=7,1,4+5 |
| 7 | CO2 | 7 | 5 | AT+COMMAND15=07 03 00 05 00 01,1 | AT+DATACUT15=7,1,4+5 |
Set the common parameters:
AT+BAUDR=9600
AT+PARITY=0
AT+STOPBIT=2
AT+TDC=600000 // 10 min (in ms)
AT+DATAUP=0 // Combine all values in one uplink
Payload Decoder
function decodeUplink(input) {
var bytes = input.bytes;
var port = input.fPort;
var data = {};
var warnings = [];
var errors = [];
// Frequency/Firmware info (usually on FPort 5)
if (port === 5) {
var bands = {
0x01: "EU868", 0x02: "US915", 0x03: "IN865", 0x04: "AU915",
0x05: "KZ865", 0x06: "RU864", 0x07: "AS923", 0x08: "AS923_1",
0x09: "AS923_2", 0x0A: "AS923_3", 0x0F: "AS923_4", 0x0B: "CN470",
0x0C: "EU433", 0x0D: "KR920", 0x0E: "MA869"
};
data.FREQUENCY_BAND = bands[bytes[0]] || "UNKNOWN";
data.SUB_BAND = (bytes[1] === 0xff) ? "NULL" : bytes[1];
data.FIRMWARE_VERSION = (bytes[2]&0x0f) + '.' + ((bytes[3]>>4)&0x0f) + '.' + (bytes[3]&0x0f);
data.TDC_sec = (bytes[4]<<16) | (bytes[5]<<8) | bytes[6];
return { data, warnings, errors };
}
// Sensor data on FPort 2 (PAYVER + device-major sensor order)
if (port === 2 && bytes.length >= 31) {
var devs = [3,4,5,6,7];
var names = ["temperature_degrC_abs", "humidity_perc_abs", "co2_ppm_abs"];
var scales = [0.1, 0.1, 1];
for (var d=0; d<devs.length; d++) { // device
for (var s=0; s<3; s++) { // sensor
var idx = d*3 + s;
var off = 1 + idx*2;
var label = names[s] + "@device" + devs[d];
if (off+1 < bytes.length) {
var raw = (bytes[off]<<8) | bytes[off+1];
if(raw & 0x8000) raw -= 0x10000;
var val = raw * scales[s];
if(s < 2) val = Math.round(val*10)/10;
data[label] = val;
} else {
data[label] = 0;
}
}
}
return { data, warnings, errors };
}
// EXTI/Payver short message (single byte)
if (port === 2 && bytes.length === 1) {
data.Node_type = "RS485-LN";
data.EXTI_Trigger = (bytes[0] & 0x80) ? "TRUE" : "FALSE";
data.Payver = bytes[0] & 0x7F;
return { data, warnings, errors };
}
errors.push("Unexpected payload: port=" + port + ", length=" + bytes.length);
return { data: {}, warnings, errors };
}