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.

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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.

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(% 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.

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(% 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.

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(% 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]]

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

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== 1.2 Specifications ==

**Hardware System:**

* STM32L072CZT6 MCU

* SX1276/78 Wireless Chip

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* Power Consumption (exclude RS485 device):

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** Idle: 32mA@12v

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** 20dB Transmit: 65mA@12v

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**Interface for Model:**

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* RS485

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* Power Input 7~~ 24V DC.

**LoRa Spec:**

* Frequency Range:

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

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

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* 168 dB maximum link budget.

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

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* +14 dBm high efficiency PA.

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* Programmable bit rate up to 300 kbps.

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* High sensitivity: down to -148 dBm.

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

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* Excellent blocking immunity.

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

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* Fully integrated synthesizer with a resolution of 61 Hz.

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

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* Built-in bit synchronizer for clock recovery.

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* Preamble detection.

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* 127 dB Dynamic Range RSSI.

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

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* Packet engine up to 256 bytes with CRC

== 1.3 Features ==

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

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

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* AT Commands to change parameters

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* Remote configure parameters via LoRa Downlink

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* Firmware upgradable via program port

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* Support multiply RS485 devices by flexible rules

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* Support Modbus protocol

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

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== 1.4 Applications ==

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* Smart Buildings & Home Automation

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* Logistics and Supply Chain Management

* Smart Metering

* Smart Agriculture

* Smart Cities

* Smart Factory

== 1.5 Firmware Change log ==

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

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== 1.6 Hardware Change log ==

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v1.2: Add External Interrupt Pin.

v1.0: Release

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= 2. Power ON Device =

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

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* Power Source VIN to RS485-LN VIN+

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* Power Source GND to RS485-LN VIN-

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

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[[image:1653268091319-405.png]]

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= 3. Operation Mode =

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== 3.1 How it works? ==

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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.

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== 3.2 Example to join LoRaWAN network ==

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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.

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

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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:

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

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

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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:

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

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

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[[image:1652953462722-299.png]]

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

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Add APP EUI in the application.

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

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

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

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

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You can also choose to create the device manually.

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

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Add APP KEY and DEV EUI

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

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**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.

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

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== 3.3 Configure Commands to read data ==

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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>>||anchor="H3.5ConfigureRS485-BLviaATorDownlink"]] or LoRaWAN Downlink Command to configure what commands RS485-LN should send for each sampling and how to handle the return from RS485 devices.

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(% 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

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

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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:

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

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

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**AT Commands**

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**Description**

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**Example**

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

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AT+BAUDR

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

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AT+BAUDR=9600

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

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

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AT+PARITY

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Set UART parity (for RS485 connection)

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AT+PARITY=0

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

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

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AT+STOPBIT

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Set serial stopbit (for RS485 connection)

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AT+STOPBIT=0 for 1bit

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AT+STOPBIT=1 for 1.5 bit

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AT+STOPBIT=2 for 2 bits

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=== 3.3.2 Configure sensors ===

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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.

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

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

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

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

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

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

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

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

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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.

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

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This section describes how to achieve above goals.

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

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**Each RS485 commands include two parts:**

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~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.

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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.

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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

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

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Below are examples for the how above AT Commands works.

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

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

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

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

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

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

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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.

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

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

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

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

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

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

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

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

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**Examples:**

* Grab bytes:

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

* Grab a section.

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

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* Grab different sections.

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

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=== 3.3.4 Compose the uplink payload ===

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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.**

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

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

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Final Payload is

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

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

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

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

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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**

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1. PAYVER: Defined by AT+PAYVER

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

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

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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

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

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

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

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

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

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(% 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:

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

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

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

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

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Below are the uplink payloads:

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[[image:1654157178836-407.png]]

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=== 3.3.5 Uplink on demand ===

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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.

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Downlink control command:

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

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

=== 3.3.6 Uplink on Interrupt ===

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

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[[image:1654157342174-798.png]]

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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.

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== 3.4 Uplink Payload ==

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

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

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

Battery(mV)

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Interrupt _Flag

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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.

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

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

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

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There are two kinds of Commands:

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* (% 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: [[AT Commands and Downlink Command>>doc:Main.End Device AT Commands and Downlink Command.WebHome]]

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

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=== 3.5.1 Common Commands ===

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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]]

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=== 3.5.2 Sensor related commands ===

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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.

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

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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)

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=== 3.5.3 Sensor related commands ===

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

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

* **AT Command**

(% class="box infomessage" %)

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

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

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* **Downlink Payload**

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Format: A8 MM NN XX XX XX XX YY

Where:

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

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* NN: The length of RS485 command

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* XX XX XX XX: RS485 command total NN bytes

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

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

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

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

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

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To connect a Modbus Alarm with below commands.

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* 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.

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* 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.

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

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

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

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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.

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

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

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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:

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

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[[image:1654159460680-153.png]]

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

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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" %)

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

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* **Downlink Payload:**

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

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

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

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AT+COMMANDx or AT+DATACUTx

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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" %)

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

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(% class="box infomessage" %)

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

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* **Downlink Payload:**

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

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

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Format: AF MM NN LL XX XX XX XX YY

Where:

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

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

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

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

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* 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

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(% 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**

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(% 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** ====

650

651

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]].

652

653

This command is valid since v1.3 firmware version

654

655

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.

661

* 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.

662

* 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.

663

664

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

665

666

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

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

671

672

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.

673

674

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

* **AT Command:**

(% class="box infomessage" %)

679

(((

680

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

)))

**Example:**

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

686

687

688

* **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** ====

701

702

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

703

704

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:**

720

721

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

722

723

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

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

728

729

Ask device to send an uplink immediately.

* **AT Command:**

No AT Command for this, user can press the [[ACT button>>||anchor="H3.7Buttons"]] for 1 second for the same.

734

735

736

* **Downlink Payload:**

737

738

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

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

743

744

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

749

750

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

751

752

Example screen shot after clear all RS485 commands.

753

754

755

The uplink screen shot is:

756

757

[[image:1654160691922-496.png]]

758

759

760

* **Downlink Payload:**

761

762

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

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

767

768

Set the Rs485 serial communication parameters:

* **AT Command:**

Set Baud Rate:

(% class="box infomessage" %)

775

(((

776

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

)))

Set UART Parity

(% class="box infomessage" %)

782

(((

783

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

)))

Set STOPBIT

(% class="box infomessage" %)

789

(((

790

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

)))

* **Downlink Payload:**

795

796

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

**Example:**

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

801

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

802

803

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

804

805

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

806

807

808

== 3.6 Listening mode for RS485 network ==

809

810

This feature support since firmware v1.4

811

812

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.

813

814

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

815

816

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

817

818

819

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

820

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

821

|(% 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.

822

|(% 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

823

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

824

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

825

826

**Downlink Command:**

827

828

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

**Example**:

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

834

835

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

836

837

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

838

839

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

840

841

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

842

843

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

844

845

846

(% 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" %)

853

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

854

|**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**

855

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

856

|**PRO**|(% style="width:1420px" %)Use for upload image, see [[How to Update Image>>||anchor="H6.1Howtoupgradetheimage3F"]]

== 3.8 LEDs ==

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

862

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

863

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

864

|**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]]

870

871

872

= 5. Use AT Command =

873

874

== 5.1 Access AT Command ==

875

876

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.

877

878

[[image:1654162355560-817.png]]

879

880

881

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:

882

883

[[image:1654162368066-342.png]]

884

885

886

More detail AT Command manual can be found at [[AT Command Manual>>https://www.dragino.com/downloads/index.php?dir=LT_LoRa_IO_Controller/LT33222-L/]]

887

888

889

== 5.2 Common AT Command Sequence ==

890

891

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

892

893

If device has not joined network yet:

894

895

(% class="box infomessage" %)

(((

**AT+FDR**

)))

(% class="box infomessage" %)

(((

**AT+NJM=0**

)))

(% class="box infomessage" %)

(((

**ATZ**

)))

If device already joined network:

912

913

(% class="box infomessage" %)

(((

**AT+NJM=0**

)))

(% class="box infomessage" %)

(((

**ATZ**

)))

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

925

926

927

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

928

929

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

930

931

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

932

933

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

934

935

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

936

937

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

938

939

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

940

941

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

942

943

(% 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.

944

945

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

946

947

948

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

949

950

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

951

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

952

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.

953

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

954

955

[[image:1654162478620-421.png]]

= 6. FAQ =

== 6.1 How to upgrade the image? ==

961

962

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

963

964

* Support new features

965

* For bug fix

966

* Change LoRaWAN bands.

967

968

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

969

970

[[image:1654162535040-878.png]]

971

972

**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]].

973

974

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

975

976

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

977

978

(((

979

(% 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.

)))

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

984

985

986

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

987

988

989

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

990

991

992

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

993

994

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

995

996

997

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

998

999

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

1000

1001

1002

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

1003

1004

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"]].

1005

1006

1007

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

1008

1009

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

1010

1011

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

1012

1013

1014

= 7. Trouble Shooting =

1015

1016

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

1017

1018

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

1019

1020

1021

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

1022

1023

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**

1029

1030

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

1031

1032

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

1033

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

1034

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

1035

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

1036

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

1037

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

1038

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

1039

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

1040

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

1041

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

= 9.Packing Info =

**Package Includes**:

1049

1050

* RS485-LN x 1

1051

* Stick Antenna for LoRa RF part x 1

1052

* Program cable x 1

1053

1054

**Dimension and weight**:

1055

1056

* Device Size: 13.5 x 7 x 3 cm

1057

* Device Weight: 105g

1058

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

1059

* Weight / pcs : 170g

1060

1061

= 10. FCC Caution for RS485LN-US915 =

1062

1063

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

1064

1065

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:

1071

1072

—Reorient or relocate the receiving antenna.

1073

1074

—Increase the separation between the equipment and receiver.

1075

1076

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

1077

1078

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

1079

1080

1081

**FCC Radiation Exposure Statement:**

1082

1083

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.

1089

* 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

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