Dragino RS485-LN User manual

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RS485-LN -- RS485 to LoRaWAN Converter User Manual
Document Version: 1.4
Image Version: v1.3.0
Version Description Date

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1.0 Release 2019-Dec-8
1.0.1 Improve product photos and network structure 2019-Dec-30
1.0.2 Add AT Command to set UART parity
1.1 Upgrade manual for v1.1 firmware version 2020-Feb-19
1.2 Add downlink command 0x09, Add Command AT+CMDDL 2020-May-16
1.3 Remove FAQ for LG01, Add FAQ for slave numbers, Add Case Study Link.
Update content for firmware v1.3
2020-Dec-5
1.4 Change to use TTN v3

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1. Introduction..............................................................................................................................5
1.1 What is RS485-LN RS485 to LoRaWAN Converter ......................................................................5
1.2 Specifications..............................................................................................................................6
1.3 Features......................................................................................................................................6
1.4 Applications................................................................................................................................6
1.5 Hardware Change log.................................................................................................................7
1.6 Installation .................................................................................................................................7
2. Power ON Device ......................................................................................................................8
3. Operation Mode .......................................................................................................................9
3.1 How it works?.............................................................................................................................9
3.2 Example to join LoRaWAN network............................................................................................9
3.3 Configure Commands to read data ..........................................................................................14
3.3.1 Configure UART settings for RS485 communication.......................................................14
3.3.2 Configure RS485 sensors ................................................................................................15
3.3.3 Configure read commands for each sampling ................................................................16
3.3.4 Compose the uplink payload ..........................................................................................18
3.3.5 Uplink on demand ..........................................................................................................20
3.3.6 Uplink on Interrupt .........................................................................................................20
3.4 Uplink Payload..........................................................................................................................20
3.5 Configure RS485-LN via AT or Downlink ...................................................................................21
3.5.1 Common Commands: .....................................................................................................21
3.5.2 Sensor related commands: .............................................................................................21
RS485 Debug Command...........................................................................................................21
Set Payload version ..................................................................................................................22
Set RS485 Sampling Commands...............................................................................................22
Fast command to handle MODBUS device...............................................................................23
RS485 command timeout.........................................................................................................24
Uplink payload mode ...............................................................................................................24
Manually trigger an Uplink.......................................................................................................24
Clear RS485 Command.............................................................................................................24
Set Serial Communication Parameters.....................................................................................25
3.6 Buttons .....................................................................................................................................25
3.7 LEDs..........................................................................................................................................26
4. Case Study ..............................................................................................................................27

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5. Use AT Command....................................................................................................................27
5.1 Access AT Command.................................................................................................................27
6. Trouble Shooting.....................................................................................................................29
6.1 Downlink doesn’t work, how to solve it?..................................................................................29
6.2 Why I can’t join TTN V3 in US915 /AU915 bands? ...................................................................29
7. Order Info ...............................................................................................................................29
8. Packing Info ............................................................................................................................29
9. FCC Caution: ...........................................................................................................................30
10. Support ..............................................................................................................................30

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1. Introduction
1.1 What is RS485-LN RS485 to LoRaWAN Converter
The Dragino RS485-LN is a RS485 to LoRaWAN Converter. It converts the RS485 signal into
LoRaWAN wireless signal which simplify the IoT installation and reduce the
installation/maintaining cost.
RS485-LN allows user to 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.
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.
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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1.2 Specifications
Hardware System:
➢STM32L072CZT6 MCU
➢SX1276 Wireless Chip
➢Power Consumption (exclude RS485 device):
Idle: 32mA@12v
20dB Transmit: 65mA@12v
Interface for Model:
➢RS485
➢Power Input 7~ 24V DC.
LoRa Spec:
➢168 dB maximum link budget.
➢Programmable bit rate up to 300 kbps.
➢High sensitivity: down to -148 dBm.
➢Bullet-proof front end: IIP3 = -12.5 dBm.
➢Excellent blocking immunity.
➢Low RX current of 10.3 mA, 200 nA register retention.
➢Fully integrated synthesizer with a resolution of 61 Hz.
➢FSK, GFSK, MSK, GMSK, LoRaTM and OOK modulation.
➢Built-in bit synchronizer for clock recovery.
➢Preamble detection.
➢127 dB Dynamic Range RSSI.
➢Automatic RF Sense and CAD with ultra-fast AFC.
➢Packet engine up to 256 bytes with CRC.
1.3 Features
✓LoRaWAN Class A & Class C protocol (default Class C)
✓Frequency Bands: CN470/EU433/KR920/US915/EU868/AS923/AU915/IN865/RU864
✓AT Commands to change parameters
✓Remote configure parameters via LoRa Downlink
✓Support multiply RS485 devices by flexible rules
✓Support Modbus protocol
✓Support Interrupt uplink (Since hardware version v1.2)
1.4 Applications
✓Smart Buildings & Home Automation
✓Logistics and Supply Chain Management

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✓Smart Metering
✓Smart Agriculture
✓Smart Cities
✓Smart Factory
1.5 Hardware Change log
v1.2
Add External Interrupt Pin.
v1.0 Release
1.6 Installation
Please ask a professional engineer to install the RS485-LN.

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2. Power ON Device
The RS485-LN can be powered by 7 ~ 24V DC power source. Connection as below
✓Power Source VIN to RS485-LN VIN+
✓Power Source GND to RS485-LN VIN-
Once there is power, the RS485-LN will be on.

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3. Operation Mode
3.1 How it works?
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
Here shows an example for how to join the TTN V3 Network. Assume user already have a
LoRaWAN Gateway and set to connect to TTN.
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:
The LG308 is already set to connect to TTN V3 network . 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:

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User can enter this key in their LoRaWAN Server portal. Below is TTN V3 screen shot:
Add APP EUI in the application.

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You can also choose to create the device manually.

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Add APP KEY and DEV EUI
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.
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 or LoRaWAN Downlink Command to configure what commands
RS485-LN should send for each sampling and how to handle the return from RS485 devices.
3.3.1 Configure UART settings for RS485 communication
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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AT Commands Description Example
AT+BAUDR Set the baud rate (for RS485 connection).
Default Value is: 9600.
AT+BAUDR=9600
Options:
(1200,2400,4800,14400,19200,115200)
AT+PARITY Set UART parity (for RS485 connection) AT+PARITY=0
Option: 0: no parity, 1: odd parity, 2: even
parity
AT+STOPBIT Set serial stopbit (for RS485 connection) AT+STOPBIT=0 for 1bit
AT+STOPBIT=1 for 1.5 bit
AT+STOPBIT=2 for 2 bits
3.3.2 Configure RS485 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 AT+CFGDEV. Each 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.
AT Commands Description Example
AT+CFGDEV This command is used to configure the RS485
devices; they won’t be used during sampling.
AT+CFGDEV=xx xx xx xx xx xx xx xx xx xx xx xx,m
m: 0: no CRC, 1: add CRC-16/MODBUS in the
end of this command
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
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.
To save the LoRaWAN network bandwidth, we might need to read data from different sensors
and combine their valid value into a short payload.
This section describes how to achieve above goals.
During each sampling, the RS485-LN can support 15 commands to read sensors. And combine the
return to one or several uplink payloads.
Each RS485 commands include two parts:
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.
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.
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
After we got the valid value from each RS485 commands, we need to combine them together
with the command AT+DATAUP.
Below are examples for the how above AT Commands works.
AT+COMMANDx : This command will be sent to RS485 devices during each sampling, Max
command length is 14 bytes. The grammar is:
AT+COMMANDx=xx xx xx xx xx xx xx xx xx xx xx xx,m
xx xx xx xx xx xx xx xx xx xx xx xx: The RS485 command to be sent
m: 0: no CRC, 1: add CRC-16/MODBUS in the end of this command
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 02,1for the
same.
AT+DATACUTx : This command defines how to handle the return from AT+COMMANDx, max
return length is 45 bytes.
AT+DATACUTx=a,b,c
a: length for the return of AT+COMMAND
b:1: grab valid value by byte, max 6 bytes. 2: grab valid value by bytes
section, max 3 sections.
c: define the position for valid value.
Examples:
➢Grab bytes:
➢Grab a section.
➢Grab different sections.

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3.3.4 Compose the uplink payload
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.
Examples: AT+DATAUP=0
Compose the uplink payload with value returns in sequence and send with A SIGNLE UPLINK.
Final Payload is
PAYVER + VALID Value from RETURN1 + Valid Value from RETURN2
+ …+ RETURNx
Where PAYVER is defined by AT+PAYVER, below is an example screen shot.

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Examples: AT+DATAUP=1
Compose the uplink payload with value returns in sequence and send with Multiply UPLINKs.
Final Payload is
PAYVER + PAYLOAD COUNT + PAYLOAD# + DATA
1) PAYVER: Defined by AT+PAYVER
2) PAYLOAD COUNT: Total how many uplinks of this sampling.
3) PAYLOAD#: Number of this uplink. (from 0,1,2,3…,to PAYLOAD COUNT)
4) 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
So totally there will be 3 uplinks for this sampling, each uplink include 8 bytes DATA
DATA1=RETURN1 Valid Value + the first two of Valid value of RETURN10= 20 20 0a 33 90 41 02 aa
DATA2=3rd ~ 10th byte of Valid value of RETURN10= 05 81 0a 20 20 20 20 2d
DATA3=the rest of Valid value of RETURN10= 30
Below are the uplink payloads:

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3.3.5 Uplink on demand
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.
Downlink control command:
0x08 command: Poll an uplink with current command set in RS485-LN.
0xA8 command: Send a command to RS485-LN and uplink the output from sensors.
3.3.6 Uplink on Interrupt
RS485-LN support external Interrupt uplink since hardware v1.2 release.
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.
3.4 Uplink Payload