RS485-LN – RS485 to LoRaWAN Converter

The Dragino RS485-LN is a (% style="color:blue" %)**RS485 to LoRaWAN Converter**(%%). It converts the RS485 signal into LoRaWAN wireless signal which simplify the IoT installation and reduce the installation/maintaining cost.

28

)))

29

30

(((

31

RS485-LN allows user to (% style="color:blue" %)**monitor / control RS485 devices**(%%) and reach extremely long ranges. It provides ultra-long range spread spectrum communication and high interference immunity whilst minimizing current consumption. It targets professional wireless sensor network applications such as irrigation systems, smart metering, smart cities, smartphone detection, building automation, and so on.

)))

(((

(% style="color:blue" %)**For data uplink**(%%), RS485-LN sends user-defined commands to RS485 devices and gets the return from the RS485 devices. RS485-LN will process these returns according to user-define rules to get the final payload and upload to LoRaWAN server.

)))

(((

(% style="color:blue" %)**For data downlink**(%%), RS485-LN runs in LoRaWAN Class C. When there downlink commands from LoRaWAN server, RS485-LN will forward the commands from LoRaWAN server to RS485 devices.

40

41

(% style="color:blue" %)**Demo Dashboard for RS485-LN**(%%) connect to two energy meters: [[https:~~/~~/app.datacake.de/dashboard/d/58844a26-378d-4c5a-aaf5-b5b5b153447a>>url:https://app.datacake.de/dashboard/d/58844a26-378d-4c5a-aaf5-b5b5b153447a]]

)))

)))

[[image:1653267211009-519.png||height="419" width="724"]]

46

47

48

== 1.2 Specifications ==

**Hardware System:**

* STM32L072CZT6 MCU

* SX1276/78 Wireless Chip

55

* Power Consumption (exclude RS485 device):

56

** Idle: 32mA@12v

57

** 20dB Transmit: 65mA@12v

58

59

**Interface for Model:**

60

61

* RS485

62

* Power Input 7~~ 24V DC.

**LoRa Spec:**

* Frequency Range:

** Band 1 (HF): 862 ~~ 1020 Mhz

68

** Band 2 (LF): 410 ~~ 528 Mhz

69

* 168 dB maximum link budget.

70

* +20 dBm - 100 mW constant RF output vs.

71

* +14 dBm high efficiency PA.

72

* Programmable bit rate up to 300 kbps.

73

* High sensitivity: down to -148 dBm.

74

* Bullet-proof front end: IIP3 = -12.5 dBm.

75

* Excellent blocking immunity.

76

* Low RX current of 10.3 mA, 200 nA register retention.

77

* Fully integrated synthesizer with a resolution of 61 Hz.

78

* FSK, GFSK, MSK, GMSK, LoRaTM and OOK modulation.

79

* Built-in bit synchronizer for clock recovery.

80

* Preamble detection.

81

* 127 dB Dynamic Range RSSI.

82

* Automatic RF Sense and CAD with ultra-fast AFC.

83

* Packet engine up to 256 bytes with CRC

== 1.3 Features ==

* LoRaWAN Class A & Class C protocol (default Class C)

90

* Frequency Bands: CN470/EU433/KR920/US915/EU868/AS923/AU915/IN865/RU864

91

* AT Commands to change parameters

92

* Remote configure parameters via LoRa Downlink

93

* Firmware upgradable via program port

94

* Support multiply RS485 devices by flexible rules

95

* Support Modbus protocol

96

* Support Interrupt uplink (Since hardware version v1.2)

== 1.4 Applications ==

101

102

* Smart Buildings & Home Automation

103

* Logistics and Supply Chain Management

* Smart Metering

* Smart Agriculture

* Smart Cities

* Smart Factory

== 1.5 Firmware Change log ==

112

113

[[RS485-LN Image files – Download link and Change log>>url:http://www.dragino.com/downloads/index.php?dir=RS485-LN/]]

114

115

116

== 1.6 Hardware Change log ==

(((

(((

v1.2: Add External Interrupt Pin.

v1.0: Release

)))

)))

= 2. Power ON Device =

129

130

(((

131

The RS485-LN can be powered by 7 ~~ 24V DC power source. Connection as below

132

133

* Power Source VIN to RS485-LN VIN+

134

* Power Source GND to RS485-LN VIN-

135

136

(((

137

Once there is power, the RS485-LN will be on.

138

)))

139

140

[[image:1653268091319-405.png]]

)))

= 3. Operation Mode =

146

147

== 3.1 How it works? ==

148

149

(((

150

The RS485-LN is configured as LoRaWAN OTAA Class C mode by default. It has OTAA keys to join network. To connect a local LoRaWAN network, user just need to input the OTAA keys in the network server and power on the RS485-LN. It will auto join the network via OTAA.

)))

== 3.2 Example to join LoRaWAN network ==

156

157

Here shows an example for how to join the TTN V3 Network. Below is the network structure, we use [[LG308>>url:http://www.dragino.com/products/lora-lorawan-gateway/item/140-lg308.html]] as LoRaWAN gateway here.

158

159

[[image:1653268155545-638.png||height="334" width="724"]]

(((

(((

The RS485-LN in this example connected to two RS485 devices for demonstration, user can connect to other RS485 devices via the same method. The connection is as below:

)))

(((

485A+ and 485B- of the sensor are connected to RS485A and RA485B of RS485-LN respectively.

169

)))

170

171

[[image:1653268227651-549.png||height="592" width="720"]]

172

173

(((

174

The LG308 is already set to connect to [[TTN V3 network >>path:https://www.thethingsnetwork.org/]]. So what we need to now is only configure the TTN V3:

)))

(((

**Step 1**: Create a device in TTN V3 with the OTAA keys from RS485-LN.

)))

(((

Each RS485-LN is shipped with a sticker with unique device EUI:

)))

)))

[[image:1652953462722-299.png]]

(((

(((

User can enter this key in their LoRaWAN Server portal. Below is TTN V3 screen shot:

)))

(((

Add APP EUI in the application.

)))

)))

[[image:image-20220519174512-1.png]]

199

200

[[image:image-20220519174512-2.png||height="323" width="720"]]

201

202

[[image:image-20220519174512-3.png||height="556" width="724"]]

203

204

[[image:image-20220519174512-4.png]]

205

206

You can also choose to create the device manually.

207

208

[[image:1652953542269-423.png||height="710" width="723"]]

209

210

Add APP KEY and DEV EUI

211

212

[[image:1652953553383-907.png||height="514" width="724"]]

(((

**Step 2**: Power on RS485-LN and it will auto join to the TTN V3 network. After join success, it will start to upload message to TTN V3 and user can see in the panel.

217

)))

218

219

[[image:1652953568895-172.png||height="232" width="724"]]

220

221

222

== 3.3 Configure Commands to read data ==

(((

(((

There are plenty of RS485 devices in the market and each device has different command to read the valid data. To support these devices in flexible, RS485-LN supports flexible command set. User can use [[AT Commands>>path:#AT_COMMAND]] or LoRaWAN Downlink Command to configure what commands RS485-LN should send for each sampling and how to handle the return from RS485 devices.

)))

(((

(% style="color:red" %)Note: below description and commands are for firmware version >v1.1, if you have firmware version v1.0. Please check the [[user manual v1.0>>url:http://www.dragino.com/downloads/index.php?dir=RS485-LN/&file=RS485-LN_UserManual_v1.0.1.pdf]] or upgrade the firmware to v1.1

)))

)))

=== 3.3.1 onfigure UART settings for RS485 or TTL communication ===

237

238

To use RS485-LN to read data from RS485 sensors, connect the RS485-LN A/B traces to the sensors. And user need to make sure RS485-LN use the match UART setting to access the sensors. The related commands for UART settings are:

239

240

(% border="1" style="background-color:#ffffcc; color:green; width:782px" %)

241

|(% style="width:128px" %)(((

242

**AT Commands**

243

)))|(% style="width:305px" %)(((

244

**Description**

245

)))|(% style="width:346px" %)(((

246

**Example**

247

)))

248

|(% style="width:128px" %)(((

249

AT+BAUDR

250

)))|(% style="width:305px" %)(((

251

Set the baud rate (for RS485 connection). Default Value is: 9600.

252

)))|(% style="width:346px" %)(((

(((

AT+BAUDR=9600

)))

(((

Options: (1200,2400,4800,14400,19200,115200)

259

)))

260

)))

261

|(% style="width:128px" %)(((

262

AT+PARITY

263

)))|(% style="width:305px" %)(((

264

Set UART parity (for RS485 connection)

265

)))|(% style="width:346px" %)(((

(((

AT+PARITY=0

)))

(((

Option: 0: no parity, 1: odd parity, 2: even parity

272

)))

273

)))

274

|(% style="width:128px" %)(((

275

AT+STOPBIT

276

)))|(% style="width:305px" %)(((

277

(((

278

Set serial stopbit (for RS485 connection)

)))

(((

)))

)))|(% style="width:346px" %)(((

285

(((

286

AT+STOPBIT=0 for 1bit

)))

(((

AT+STOPBIT=1 for 1.5 bit

)))

(((

AT+STOPBIT=2 for 2 bits

)))

)))

=== 3.3.2 Configure sensors ===

(((

(((

Some sensors might need to configure before normal operation. User can configure such sensor via PC and RS485 adapter or through RS485-LN AT Commands (% style="color:#4f81bd" %)**AT+CFGDEV**(%%). Each (% style="color:#4f81bd" %)**AT+CFGDEV **(%%)equals to send a RS485 command to sensors. This command will only run when user input it and won’t run during each sampling.

)))

)))

(% border="1" style="background-color:#ffffcc; color:green; width:806px" %)

307

|**AT Commands**|(% style="width:418px" %)**Description**|(% style="width:256px" %)**Example**

308

|AT+CFGDEV|(% style="width:418px" %)(((

309

This command is used to configure the RS485/TTL devices; they won’t be used during sampling.

310

311

AT+CFGDEV=xx xx xx xx xx xx xx xx xx xx xx xx,

312

313

mm: 0: no CRC, 1: add CRC-16/MODBUS in the end of this command

314

)))|(% style="width:256px" %)AT+CFGDEV=xx xx xx xx xx xx xx xx xx xx xx xx,m

315

316

=== 3.3.3 Configure read commands for each sampling ===

317

318

(((

319

During each sampling, we need confirm what commands we need to send to the RS485 sensors to read data. After the RS485 sensors send back the value, it normally include some bytes and we only need a few from them for a shorten payload.

320

321

To save the LoRaWAN network bandwidth, we might need to read data from different sensors and combine their valid value into a short payload.

322

323

This section describes how to achieve above goals.

324

325

During each sampling, the RS485-LN can support 15 commands to read sensors. And combine the return to one or several uplink payloads.

326

327

328

**Each RS485 commands include two parts:**

329

330

~1. What commands RS485-LN will send to the RS485 sensors. There are total 15 commands from **AT+COMMAD1**, **ATCOMMAND2**,…, to **AT+COMMANDF**. All commands are of same grammar.

331

332

2. How to get wanted value the from RS485 sensors returns from by 1). There are total 15 AT Commands to handle the return, commands are **AT+DATACUT1**,**AT+DATACUT2**,…, **AT+DATACUTF** corresponding to the commands from 1). All commands are of same grammar.

333

334

3. Some RS485 device might has longer delay on reply, so user can use AT+CMDDL to set the timeout for getting reply after the RS485 command is sent. For example **AT+CMDDL1=1000** to send the open time to 1000ms

335

336

337

After we got the valid value from each RS485 commands, we need to combine them together with the command **AT+DATAUP**.

338

339

340

Below are examples for the how above AT Commands works.

341

342

343

**AT+COMMANDx : **This command will be sent to RS485 devices during each sampling, Max command length is 14 bytes. The grammar is:

344

345

(% border="1" style="background-color:#4bacc6; color:white; width:499px" %)

346

|(% style="width:496px" %)(((

347

**AT+COMMANDx=xx xx xx xx xx xx xx xx xx xx xx xx,m**

348

349

**xx xx xx xx xx xx xx xx xx xx xx xx: The RS485 command to be sent**

350

351

**m: 0: no CRC, 1: add CRC-16/MODBUS in the end of this command**

352

)))

353

354

For example, if we have a RS485 sensor. The command to get sensor value is: 01 03 0B B8 00 02 46 0A. Where 01 03 0B B8 00 02 is the Modbus command to read the register 0B B8 where stored the sensor value. The 46 0A is the CRC-16/MODBUS which calculate manually.

355

356

In the RS485-LN, we should use this command AT+COMMAND1=01 03 0B B8 00 02,1 for the same.

357

358

359

**AT+DATACUTx : **This command defines how to handle the return from AT+COMMANDx, max return length is 45 bytes.

360

361

(% border="1" style="background-color:#4bacc6; color:white; width:725px" %)

362

|(% style="width:722px" %)(((

363

**AT+DATACUTx=a,b,c**

364

365

* **a: length for the return of AT+COMMAND**

366

* **b:1: grab valid value by byte, max 6 bytes. 2: grab valid value by bytes section, max 3 sections.**

367

* **c: define the position for valid value. **

)))

**Examples:**

* Grab bytes:

[[image:image-20220602153621-1.png]]

* Grab a section.

[[image:image-20220602153621-2.png]]

380

381

382

* Grab different sections.

383

384

[[image:image-20220602153621-3.png]]

)))

=== 3.3.4 Compose the uplink payload ===

390

391

(((

392

Through AT+COMMANDx and AT+DATACUTx we got valid value from each RS485 commands, Assume these valid value are RETURN1, RETURN2, .., to RETURNx. The next step is how to compose the LoRa Uplink Payload by these RETURNs. The command is **AT+DATAUP.**

)))

(((

(% style="color:#037691" %)**Examples: AT+DATAUP=0**

)))

(((

Compose the uplink payload with value returns in sequence and send with (% style="color:red" %)**A SIGNLE UPLINK**.

)))

(((

Final Payload is

)))

(((

(% style="color:#4f81bd" %)**Battery Info+PAYVER + VALID Value from RETURN1 + Valid Value from RETURN2 + … + RETURNx**

)))

(((

Where PAYVER is defined by AT+PAYVER, below is an example screen shot.

417

)))

418

419

[[image:1653269759169-150.png||height="513" width="716"]]

420

421

422

(% style="color:#037691" %)**Examples: AT+DATAUP=1**

423

424

425

Compose the uplink payload with value returns in sequence and send with (% style="color:red" %)**Multiply UPLINKs**.

Final Payload is

(% style="color:#4f81bd" %)**Battery Info+PAYVER + PAYLOAD COUNT + PAYLOAD# + DATA**

430

431

1. PAYVER: Defined by AT+PAYVER

432

1. PAYLOAD COUNT: Total how many uplinks of this sampling.

433

1. PAYLOAD#: Number of this uplink. (from 0,1,2,3…,to PAYLOAD COUNT)

434

1. DATA: Valid value: max 8 bytes for each uplink so each uplink <= 11 bytes. For the last uplink, DATA will might less than 8 bytes

435

436

[[image:image-20220602155039-4.png]]

437

438

439

So totally there will be 3 uplinks for this sampling, each uplink include 8 bytes DATA

440

441

DATA1=RETURN1 Valid Value + the first two of Valid value of RETURN10= **20 20 0a 33 90 41 02 aa**

442

443

DATA2=3^^rd^^ ~~ 10^^th^^ byte of Valid value of RETURN10= **05 81 0a 20 20 20 20 2d**

444

445

DATA3=the rest of Valid value of RETURN10= **30**

446

447

448

(% style="color:red" %)Notice: In firmware v1.3, the Max bytes has been changed according to the max bytes in different Frequency Bands for lowest SF. As below:

449

450

~* For AU915/AS923 bands, if UplinkDwell time=0, max 51 bytes for each uplink.

451

452

* For AU915/AS923 bands, if UplinkDwell time=0, max 11 bytes for each uplink.

453

454

* For US915 band, max 11 bytes for each uplink.

455

456

~* For all other bands: max 51 bytes for each uplink.

457

458

459

Below are the uplink payloads:

460

461

[[image:1654157178836-407.png]]

462

463

464

=== 3.3.5 Uplink on demand ===

465

466

Except uplink periodically, RS485-LN is able to uplink on demand. The server send downlink command to RS485-LN and RS485 will uplink data base on the command.

467

468

Downlink control command:

469

470

**0x08 command**: Poll an uplink with current command set in RS485-LN.

471

472

**0xA8 command**: Send a command to RS485-LN and uplink the output from sensors.

=== 3.3.6 Uplink on Interrupt ===

477

478

RS485-LN support external Interrupt uplink since hardware v1.2 release.

479

480

[[image:1654157342174-798.png]]

481

482

Connect the Interrupt pin to RS485-LN INT port and connect the GND pin to V- port. When there is a high voltage (Max 24v) on INT pin. Device will send an uplink packet.

483

484

485

== 3.4 Uplink Payload ==

486

487

(% border="1" style="background-color:#4bacc6; color:white; width:734px" %)

488

|**Size(bytes)**|(% style="width:120px" %)**2**|(% style="width:116px" %)**1**|(% style="width:386px" %)**Length depends on the return from the commands**

489

|Value|(% style="width:120px" %)(((

Battery(mV)

&

Interrupt _Flag

)))|(% style="width:116px" %)(((

PAYLOAD_VER

)))|(% style="width:386px" %)If the valid payload is too long and exceed the maximum support payload length in server, server will show payload not provided in the LoRaWAN server.

500

501

Below is the decoder for the first 3 bytes. The rest bytes are dynamic depends on different RS485 sensors.

502

503

504

== 3.5 Configure RS485-BL via AT or Downlink ==

505

506

User can configure RS485-LN via AT Commands or LoRaWAN Downlink Commands

507

508

There are two kinds of Commands:

509

510

* (% style="color:#4f81bd" %)**Common Commands**(%%): They should be available for each sensor, such as: change uplink interval, reset device. For firmware v1.3, user can find what common commands it supports: [[End Device AT Commands and Downlink Command>>doc:Main.End Device AT Commands and Downlink Command.WebHome]]

511

512

* (% style="color:#4f81bd" %)**Sensor Related Commands**(%%): These commands are special designed for RS485-LN. User can see these commands below:

513

514

=== 3.5.1 Common Commands ===

515

516

They should be available for each of Dragino Sensors, such as: change uplink interval, reset device. For firmware v1.3, user can find what common commands it supports: [[End Device AT Commands and Downlink Command>>doc:Main.End Device AT Commands and Downlink Command.WebHome]]

517

518

519

=== 3.5.2 Sensor related commands ===

520

521

Response feature is added to the server's downlink, a special package with a FPort of 200 will be uploaded immediately after receiving the data sent by the server.

522

523

[[image:image-20220602163333-5.png||height="263" width="1160"]]

524

525

The first byte of this package represents whether the configuration is successful, 00 represents failure, 01 represents success. Except for the first byte, the other is the previous downlink. (All commands except A8 type commands are applicable)

526

527

528

=== 3.5.3 Sensor related commands ===

529

530

(% class="wikigeneratedid" id="H" %)

==== **RS485 Debug Command** ====

535

536

This command is used to configure the RS485 devices; they won’t be used during sampling.

* **AT Command**

(% class="box infomessage" %)

541

(((

542

**AT+CFGDEV=xx xx xx xx xx xx xx xx xx xx xx xx,m**

543

)))

544

545

m: 0: no CRC, 1: add CRC-16/MODBUS in the end of this command

546

547

* **Downlink Payload**

548

549

Format: A8 MM NN XX XX XX XX YY

Where:

* MM: 1: add CRC-16/MODBUS ; 0: no CRC

554

* NN: The length of RS485 command

555

* XX XX XX XX: RS485 command total NN bytes

556

* YY: How many bytes will be uplink from the return of this RS485 command,

557

** if YY=0, RS485-LN will execute the downlink command without uplink;

558

** if YY>0, RS485-LN will uplink total YY bytes from the output of this RS485 command; Fport=200

559

** if YY=FF, RS485-LN will uplink RS485 output with the downlink command content; Fport=200.

560

561

**Example 1** ~-~-> Configure without ask for uplink (YY=0)

562

563

To connect a Modbus Alarm with below commands.

564

565

* The command to active alarm is: 0A 05 00 04 00 01 4C B0. Where 0A 05 00 04 00 01 is the Modbus command to read the register 00 40 where stored the DI status. The 4C B0 is the CRC-16/MODBUS which calculate manually.

566

567

* The command to deactivate alarm is: 0A 05 00 04 00 00 8D 70. Where 0A 05 00 04 00 00 is the Modbus command to read the register 00 40 where stored the DI status. The 8D 70 is the CRC-16/MODBUS which calculate manually.

568

569

So if user want to use downlink command to control to RS485 Alarm, he can use:

570

571

(% style="color:#4f81bd" %)**A8 01 06 0A 05 00 04 00 01 00**(%%): to activate the RS485 Alarm

572

573

(% style="color:#4f81bd" %)**A8 01 06 0A 05 00 04 00 00 00**(%%): to deactivate the RS485 Alarm

574

575

A8 is type code and 01 means add CRC-16/MODBUS at the end, the 3^^rd^^ byte is 06, means the next 6 bytes are the command to be sent to the RS485 network, the final byte 00 means this command don’t need to acquire output.

576

577

578

**Example 2** ~-~-> Configure with requesting uplink and original downlink command (**YY=FF**)

579

580

User in IoT server send a downlink command: (% style="color:#4f81bd" %)**A8 01 06 0A 08 00 04 00 01 YY**

581

582

583

RS485-LN got this downlink command and send (% style="color:#4f81bd" %)**0A 08 00 04 00 01 **(%%)to Modbus network. One of the RS485 sensor in the network send back Modbus reply **0A 08 00 04 00 00**. RS485-LN get this reply and combine with the original downlink command and uplink. The uplink message is:

584

585

**A8** (% style="color:#4f81bd" %)**0A 08 00 04 00 **(% style="color:red" %)**01 06** ** **(% style="color:green" %)**0A 08 00 04 00 00**

586

587

[[image:1654159460680-153.png]]

==== **Set Payload version** ====

592

593

This is the first byte of the uplink payload. RS485-BL can connect to different sensors. User can set the PAYVER field to tell server how to decode the current payload.

* **AT Command:**

(% class="box infomessage" %)

598

(((

599

**AT+PAYVER: Set PAYVER field = 1**

600

)))

601

602

* **Downlink Payload:**

603

604

**0xAE 01** ~-~-> Set PAYVER field = 0x01

605

606

**0xAE 0F** ~-~-> Set PAYVER field = 0x0F

==== **Set RS485 Sampling Commands** ====

611

612

AT+COMMANDx or AT+DATACUTx

613

614

These three commands are used to configure how the RS485-LN polling data from Modbus device. Detail of usage please see : [[polling RS485 device>>||anchor="H3.3.3Configurereadcommandsforeachsampling"]].

* **AT Command:**

(% class="box infomessage" %)

620

(((

621

**AT+COMMANDx: Configure RS485 read command to sensor.**

622

)))

623

624

(% class="box infomessage" %)

625

(((

626

**AT+DATACUTx: Configure how to handle return from RS485 devices.**

)))

* **Downlink Payload:**

631

632

**0xAF** downlink command can be used to set AT+COMMANDx or AT+DATACUTx.

633

634

(% style="color:red" %)**Note**(%%): if user use AT+COMMANDx to add a new command, he also need to send AT+DATACUTx downlink.

635

636

Format: AF MM NN LL XX XX XX XX YY

Where:

* MM: the ATCOMMAND or AT+DATACUT to be set. Value from 01 ~~ 0F,

641

* NN: 0: no CRC; 1: add CRC-16/MODBUS ; 2: set the AT+DATACUT value.

642

* LL: The length of AT+COMMAND or AT+DATACUT command

643

* XX XX XX XX: AT+COMMAND or AT+DATACUT command

644

* YY: If YY=0, RS485-BL will execute the downlink command without uplink; if YY=1, RS485-LN will execute an uplink after got this command.

**Example:**

(% style="color:#037691" %)**AF 03 01 06 0A 05 00 04 00 01 00**(%%): Same as AT+COMMAND3=0A 05 00 04 00 01,1

649

650

(% style="color:#037691" %)**AF 03 02 06**(% style="color:orange" %)** 10 **(% style="color:red" %)**01 **(% style="color:green" %)**05 06 09 0A**(% style="color:#037691" %)** 00**(%%): Same as AT+DATACUT3=(% style="color:orange" %)**16**(%%),(% style="color:red" %)**1**(%%),(% style="color:green" %)**5+6+9+10**

651

652

(% style="color:#037691" %)**AF 03 02 06 **(% style="color:orange" %)**0B**(% style="color:red" %)** 02 **(% style="color:green" %)**05 07 08 0A **(% style="color:#037691" %)**00**(%%): Same as AT+DATACUT3=(% style="color:orange" %)**11**(%%),(% style="color:red" %)**2**(%%),(% style="color:green" %)**5~~7+8~~10**

==== **Fast command to handle MODBUS device** ====

657

658

AT+MBFUN is valid since v1.3 firmware version. The command is for fast configure to read Modbus devices. It is only valid for the devices which follow the [[MODBUS-RTU protocol>>url:https://www.modbustools.com/modbus.html]].

659

660

This command is valid since v1.3 firmware version

661

662

AT+MBFUN can auto read the Modbus function code: 01, 02, 03 or 04. AT+MBFUN has lower priority vs AT+DATACUT command. If AT+DATACUT command is configured, AT+MBFUN will be ignore.

**Example:**

* AT+MBFUN=1 and AT+DATACUT1/AT+DATACUT2 are not configure (0,0,0). So RS485-LN.

668

* AT+COMMAND1= 01 03 00 10 00 08,1 ~-~-> read slave address 01 , function code 03, start address 00 01, quantity of registers 00 08.

669

* AT+COMMAND2= 01 02 00 40 00 10,1 ~-~-> read slave address 01 , function code 02, start address 00 40, quantity of inputs 00 10.

670

671

[[image:image-20220602165351-6.png]]

672

673

[[image:image-20220602165351-7.png]]

==== **RS485 command timeout** ====

678

679

Some Modbus device has slow action to send replies. This command is used to configure the RS485-LN to use longer time to wait for their action.

680

681

Default value: 0, range: 0 ~~ 65 seconds

* **AT Command:**

(% class="box infomessage" %)

686

(((

687

**AT+CMDDLaa=hex(bb cc)*1000**

)))

**Example:**

**AT+CMDDL1=1000** to send the open time to 1000ms

693

694

695

* **Downlink Payload:**

**0x AA aa bb cc**

Same as: AT+CMDDLaa=hex(bb cc)*1000

**Example:**

0xAA 01 00 01 ~-~-> Same as **AT+CMDDL1=1000 ms**

==== **Uplink payload mode** ====

708

709

Define to use one uplink or multiple uplinks for the sampling.

710

711

The use of this command please see: [[Compose Uplink payload>>||anchor="H3.3.4Composetheuplinkpayload"]]

* **AT Command:**

(% class="box infomessage" %)

(((

**AT+DATAUP=0**

)))

(% class="box infomessage" %)

(((

**AT+DATAUP=1**

)))

* **Downlink Payload:**

727

728

**0xAD 00** **~-~->** Same as AT+DATAUP=0

729

730

**0xAD 01** **~-~->** Same as AT+DATAUP=1

==== **Manually trigger an Uplink** ====

735

736

Ask device to send an uplink immediately.

* **AT Command:**

No AT Command for this, user can press the [[ACT button>>path:#Button]] for 1 second for the same.

741

742

743

* **Downlink Payload:**

744

745

**0x08 FF**, RS485-LN will immediately send an uplink.

746

747

748

(% class="wikigeneratedid" id="H-1" %)

749

750

751

==== **Clear RS485 Command** ====

752

753

The AT+COMMANDx and AT+DATACUTx settings are stored in special location, user can use below command to clear them.

* **AT Command:**

**AT+CMDEAR=mm,nn** mm: start position of erase ,nn: stop position of erase

758

759

Etc. AT+CMDEAR=1,10 means erase AT+COMMAND1/AT+DATACUT1 to AT+COMMAND10/AT+DATACUT10

760

761

Example screen shot after clear all RS485 commands.

762

763

764

The uplink screen shot is:

765

766

[[image:1654160691922-496.png]][[image:file:///C:/Users/93456/AppData/Local/Temp/msohtmlclip1/01/clip_image001.png]]

767

768

769

* **Downlink Payload:**

770

771

**0x09 aa bb** same as AT+CMDEAR=aa,bb

==== **Set Serial Communication Parameters** ====

776

777

Set the Rs485 serial communication parameters:

* **AT Command:**

Set Baud Rate:

(% class="box infomessage" %)

784

(((

785

**AT+BAUDR=9600** ~/~/ Options: (1200,2400,4800,14400,19200,115200)

)))

Set UART Parity

(% class="box infomessage" %)

791

(((

792

**AT+PARITY=0** ~/~/ Option: 0: no parity, 1: odd parity, 2: even parity

)))

Set STOPBIT

(% class="box infomessage" %)

798

(((

799

**AT+STOPBIT=0** ~/~/ Option: 0 for 1bit; 1 for 1.5 bit ; 2 for 2 bits

)))

* **Downlink Payload:**

804

805

**A7 01 aa bb**: Same AT+BAUDR=hex(aa bb)*100

**Example:**

* A7 01 00 60 same as AT+BAUDR=9600

810

* A7 01 04 80 same as AT+BAUDR=115200

811

812

A7 02 aa: Same as AT+PARITY=aa (aa value: 00 , 01 or 02)

813

814

A7 03 aa: Same as AT+STOPBIT=aa (aa value: 00 , 01 or 02)

815

816

817

== 3.6 Listening mode for RS485 network ==

818

819

This feature support since firmware v1.4

820

821

RS485-LN supports listening mode, it can listen the RS485 network packets and send them via LoRaWAN uplink. Below is the structure. The blue arrow shows the RS485 network packets to RS485-LN.

822

823

[[image:image-20220602171200-8.png||height="567" width="1007"]]

824

825

To enable the listening mode, use can run the command AT+RXMODE.

826

827

828

(% border="1" style="background-color:#ffffcc; width:500px" %)

829

|=(% style="width: 161px;" %)**Command example:**|=(% style="width: 337px;" %)**Function**

830

|(% style="width:161px" %)AT+RXMODE=1,10 |(% style="width:337px" %)Enable listening mode 1, if RS485-LN has received more than 10 RS485 commands from the network. RS485-LN will send these commands via LoRaWAN uplinks.

831

|(% style="width:161px" %)AT+RXMODE=2,500|(% style="width:337px" %)Enable listening mode 2, RS485-LN will capture and send a 500ms content once from the first detect of character. Max value is 65535 ms

832

|(% style="width:161px" %)AT+RXMODE=0,0|(% style="width:337px" %)Disable listening mode. This is the default settings.

833

|(% style="width:161px" %) |(% style="width:337px" %)A6 aa bb cc same as AT+RXMODE=aa,(bb<<8 ~| cc)

834

835

**Downlink Command:**

836

837

**0xA6 aa bb cc ** same as AT+RXMODE=aa,(bb<<8 | cc)

**Example**:

The RS485-LN is set to AT+RXMODE=2,1000

843

844

There is a two Modbus commands in the RS485 network as below:

845

846

The Modbus master send a command: (% style="background-color:#ffc000" %)01 03 00 00 00 02 c4 0b

847

848

And Modbus slave reply with: (% style="background-color:green" %)01 03 04 00 00 00 00 fa 33

849

850

RS485-LN will capture both and send the uplink: (% style="background-color:#ffc000" %)01 03 00 00 00 02 c4 0b (% style="background-color:green" %)01 03 04 00 00 00 00 fa 33

851

852

[[image:image-20220602171200-9.png]]

853

854

855

(% style="color:red" %)Notice: Listening mode can work with the default polling mode of RS485-LN. When RS485-LN is in to send the RS485 commands (from AT+COMMANDx), the listening mode will be interrupt for a while.

== 3.7 Buttons ==

(% border="1" style="background-color:#f7faff; width:500px" %)

862

|=**Button**|=(% style="width: 1420px;" %)**Feature**

863

|**ACT**|(% style="width:1420px" %)If RS485 joined in network, press this button for more than 1 second, RS485 will upload a packet, and the SYS LED will give a (% style="color:blue" %)**Blue blink**

864

|**RST**|(% style="width:1420px" %)Reboot RS485

865

|**PRO**|(% style="width:1420px" %)Use for upload image, see [[How to Update Image>>path:#upgrade_image]]

== 3.8 LEDs ==

(% border="1" style="background-color:#f7faff; width:500px" %)

872

|=**LEDs**|=**Feature**

873

|**PWR**|Always on if there is power

874

|**SYS**|After device is powered on, the SYS will (% style="color:green" %)**fast blink in GREEN** (%%)for 5 times, means RS485-LN start to join LoRaWAN network. If join success, SYS will be (% style="color:green" %)**on GREEN for 5 seconds**(%%)**. **SYS will (% style="color:green" %)**blink Blue**(%%) on every upload and (% style="color:green" %)**blink Green**(%%) once receive a downlink message.

= 4. Case Study =

User can check this URL for some case studies: [[APP RS485 COMMUNICATE WITH SENSORS>>doc:Main.Application Note \: Communicate with Different Sensors ----- RS485-LN RS485-BL.WebHome]]

881

882

883

= 5. Use AT Command =

884

885

== 5.1 Access AT Command ==

886

887

RS485-BL supports AT Command set. User can use a USB to TTL adapter plus the 3.5mm Program Cable to connect to RS485-BL to use AT command, as below.

888

889

[[image:1654162355560-817.png]]

890

891

892

In PC, User needs to set (% style="color:blue" %)**serial tool**(%%)(such as [[putty>>url:https://www.chiark.greenend.org.uk/~~sgtatham/putty/latest.html]], SecureCRT) baud rate to (% style="color:green" %)**9600**(%%) to access to access serial console of RS485-BL. The default password is 123456. Below is the output for reference:

893

894

[[image:1654162368066-342.png]]

895

896

897

More detail AT Command manual can be found at [[AT Command Manual>>||anchor="3.5ConfigureRS485-BLviaATorDownlink"]]

898

899

900

== 5.2 Common AT Command Sequence ==

901

902

=== 5.2.1 Multi-channel ABP mode (Use with SX1301/LG308) ===

903

904

If device has not joined network yet:

905

906

(% class="box infomessage" %)

(((

**AT+FDR**

)))

(% class="box infomessage" %)

(((

**AT+NJM=0**

)))

(% class="box infomessage" %)

(((

**ATZ**

)))

If device already joined network:

923

924

(% class="box infomessage" %)

(((

**AT+NJM=0**

)))

(% class="box infomessage" %)

(((

**ATZ**

)))

=== 5.5.2 Single-channel ABP mode (Use with LG01/LG02) ===

936

937

938

(% style="background-color:#dcdcdc" %)**AT+FDR** (%%) Reset Parameters to Factory Default, Keys Reserve

939

940

(% style="background-color:#dcdcdc" %)**AT+NJM=0 **(%%)Set to ABP mode

941

942

(% style="background-color:#dcdcdc" %)**AT+ADR=0** (%%)Set the Adaptive Data Rate Off

943

944

(% style="background-color:#dcdcdc" %)**AT+DR=5** (%%)Set Data Rate

945

946

(% style="background-color:#dcdcdc" %)**AT+TDC=60000** (%%) Set transmit interval to 60 seconds

947

948

(% style="background-color:#dcdcdc" %)**AT+CHS=868400000**(%%) Set transmit frequency to 868.4Mhz

949

950

(% style="background-color:#dcdcdc" %)**AT+RX2FQ=868400000** (%%) Set RX2Frequency to 868.4Mhz (according to the result from server)

951

952

(% style="background-color:#dcdcdc" %)**AT+RX2DR=5** (%%) Set RX2DR to match the downlink DR from server. see below

953

954

(% style="background-color:#dcdcdc" %)**AT+DADDR=26** (%%) 01 1A F1 Set Device Address to 26 01 1A F1, this ID can be found in the LoRa Server portal.

955

956

(% style="background-color:#dcdcdc" %)**ATZ** (%%) Reset MCU

957

958

959

(% style="color:red" %)**Note:**

960

961

(% style="color:red" %)1. Make sure the device is set to ABP mode in the IoT Server.

962

2. Make sure the LG01/02 gateway RX frequency is exactly the same as AT+CHS setting.

963

3. Make sure SF / bandwidth setting in LG01/LG02 match the settings of AT+DR. refer [[this link>>url:http://www.dragino.com/downloads/index.php?dir=LoRa_Gateway/&file=LoRaWAN%201.0.3%20Regional%20Parameters.xlsx]] to see what DR means.

964

4. The command AT+RX2FQ and AT+RX2DR is to let downlink work. to set the correct parameters, user can check the actually downlink parameters to be used. As below. Which shows the RX2FQ should use 868400000 and RX2DR should be 5

965

966

[[image:1654162478620-421.png]]

= 6. FAQ =

== 6.1 How to upgrade the image? ==

972

973

The RS485-LN LoRaWAN Controller is shipped with a 3.5mm cable, the cable is used to upload image to RS485-LN to:

974

975

* Support new features

976

* For bug fix

977

* Change LoRaWAN bands.

978

979

Below shows the hardware connection for how to upload an image to RS485-LN:

980

981

[[image:1654162535040-878.png]]

982

983

**Step1:** Download [[flash loader>>url:https://www.st.com/content/st_com/en/products/development-tools/software-development-tools/stm32-software-development-tools/stm32-programmers/flasher-stm32.html]].

984

985

**Step2**: Download the [[LT Image files>>url:http://www.dragino.com/downloads/index.php?dir=LT_LoRa_IO_Controller/LT33222-L/image/]].

986

987

**Step3: **Open flashloader; choose the correct COM port to update.

988

989

(% style="color:blue" %) Hold down the PRO button and then momentarily press the RST reset button and the SYS led will change from OFF to ON, While SYS LED is RED ON, it means the RS485-LN is ready to be program.

990

991

992

[[image:image-20220602175818-12.png]]

993

994

995

[[image:image-20220602175848-13.png]]

996

997

998

[[image:image-20220602175912-14.png]]

999

1000

1001

**Notice**: In case user has lost the program cable. User can hand made one from a 3.5mm cable. The pin mapping is:

1002

1003

[[image:image-20220602175638-10.png]]

1004

1005

1006

== 6.2 How to change the LoRa Frequency Bands/Region? ==

1007

1008

User can follow the introduction for [[how to upgrade image>>||anchor="H6.1Howtoupgradetheimage3F"]]. When download the images, choose the required image file for download.

1009

1010

1011

== 6.3 How many RS485-Slave can RS485-BL connects? ==

1012

1013

The RS485-BL can support max 32 RS485 devices. Each uplink command of RS485-BL can support max 16 different RS485 command. So RS485-BL can support max 16 RS485 devices pre-program in the device for uplink. For other devices no pre-program, user can use the [[downlink message (type code 0xA8) to poll their info>>||anchor="H3.3.3Configurereadcommandsforeachsampling"]].

1014

1015

1016

== 6.4 Compatible question to ChirpStack and TTI LoRaWAN server ? ==

1017

1018

When user need to use with ChirpStack or TTI. Please set AT+RPL=4.

1019

1020

Detail info check this link: [[Set Packet Receiving Response Level>>doc:Main.End Device AT Commands and Downlink Command.WebHome||anchor="H7.23SetPacketReceivingResponseLevel"]]

1021

1022

1023

= 7. Trouble Shooting =

1024

1025

== 7.1 Downlink doesn’t work, how to solve it? ==

1026

1027

Please see this link for debug: [[LoRaWAN Communication Debug>>doc:Main.LoRaWAN Communication Debug.WebHome]]

1028

1029

1030

== 7.2 Why I can’t join TTN V3 in US915 /AU915 bands? ==

1031

1032

It might about the channels mapping. Please see for detail: [[Notice of Frequency band>>doc:Main.LoRaWAN Communication Debug.WebHome||anchor="H2.NoticeofUS9152FCN4702FAU915Frequencyband"]]

= 8. Order Info =

(% style="color:blue" %)**Part Number: RS485-LN-XXX**

1038

1039

(% style="color:blue" %)**XXX:**

1040

1041

* (% style="color:blue" %)**EU433**(%%): frequency bands EU433

1042

* (% style="color:blue" %)**EU868**(%%): frequency bands EU868

1043

* (% style="color:blue" %)**KR920**(%%): frequency bands KR920

1044

* (% style="color:blue" %)**CN470**(%%): frequency bands CN470

1045

* (% style="color:blue" %)**AS923**(%%): frequency bands AS923

1046

* (% style="color:blue" %)**AU915**(%%): frequency bands AU915

1047

* (% style="color:blue" %)**US915**(%%): frequency bands US915

1048

* (% style="color:blue" %)**IN865**(%%): frequency bands IN865

1049

* (% style="color:blue" %)**RU864**(%%): frequency bands RU864

1050

* (% style="color:blue" %)**KZ865**(%%): frequency bands KZ865

= 9.Packing Info =

**Package Includes**:

1058

1059

* RS485-LN x 1

1060

* Stick Antenna for LoRa RF part x 1

1061

* Program cable x 1

1062

1063

**Dimension and weight**:

1064

1065

* Device Size: 13.5 x 7 x 3 cm

1066

* Device Weight: 105g

1067

* Package Size / pcs : 14.5 x 8 x 5 cm

1068

* Weight / pcs : 170g

= 10. FCC Caution for RS485LN-US915 =

1073

1074

Any Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.

1075

1076

This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

**IMPORTANT NOTE:**

**Note: **This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

1082

1083

—Reorient or relocate the receiving antenna.

1084

1085

—Increase the separation between the equipment and receiver.

1086

1087

—Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

1088

1089

—Consult the dealer or an experienced radio/TV technician for help.

1090

1091

1092

**FCC Radiation Exposure Statement:**

1093

1094

This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment.This equipment should be installed and operated with minimum distance 20cm between the radiator& your body.

= 11. Support =

* Support is provided Monday to Friday, from 09:00 to 18:00 GMT+8. Due to different timezones we cannot offer live support. However, your questions will be answered as soon as possible in the before-mentioned schedule.

1100

* Provide as much information as possible regarding your enquiry (product models, accurately describe your problem and steps to replicate it etc) and send a mail to [[support@dragino.com>>url:file:///D:/市场资料/说明书/LoRa/LT系列/support@dragino.com]].

Wiki source code of RS485-LN – RS485 to LoRaWAN Converter