LR200EM – Modbus TCP to RTU over LoRa

1 x Ethernet
1200~38.4K bps with Star function
Output power 20 dBm
Distance up to 5 km

Overview & DiagramSetup & GroupingData RateDistanceSpecificationsInquiryDownload

LoRa is ideal for transmission in a long distance with small data packet less than 200 bytes such as sensor’s data of which packet size is usually 30~40 bytes.

Modbus TCP to Modbus TCP over LoRa

Modbus TCP to Modbus RTU/ASCII
Modbus RTU/ASCII to Modbus TCP

Scada Modbus TCP to Modbus RTU
Modbus RTU to Scada Modbus TCP

Modbus TCP to Digital I/O

Modbus TCP to Analog Inputs

Power off LR200EM and open the casing.
Carefully finger pinch the LoRa board to lift it up slowly till off the main board.

A LR200S main board is needed to set up the LoRa settings.
Power off LR200S and open casing.
Replace the original LoRa board on LR200S main board with LR200EM LoRa board.
Adjust LR200EM LoRa board dip switch to enter into SETUP mode (refer to manual to see how)
Connect the LR200S to PC with a RS232 crosslink cable (NOT Pin to Pin parallel cable)
Power on LR200S
Run LoRa setup tool from PC (see below image)

Click to choose the COM port where the LR200S main board is connected with.
Click “Read” to read out current settings of the LoRa module.
Set up “Pass Mode” and “Device ID” as 0, “Interface” as RS485.
“Encryption Key” must be 32 digits.
Ignore “Channel Scan” at the bottom.
Make necessary adjustments for the rest of settings and click “Write” to save settings to LoRa module when done.
Power off LR200S.
Restore LR200EM LoRa board dip switch back to OPERATION mode.
Remove LR200EM LoRa board from LR200S and Restore the original LoRa board back to LR200S main board.
Restore LR200S casing.
Restore LR200EM LoRa board back to LR200EM main board.
Restore LR200EM casing.

LoRa Grouping

LoRa converters with the same Encryption key and same Frequency will be automatically grouped together when they are powered on and able to broadcast to all grouped LoRa converters.
Any two LoRa converters with different Encryption Key and/or different Frequency will not be grouped together.

Assuming Group A is 920 MHz and Group B is 920.1 MHz, both A and B have the same key, in theory, Group A and B will not be grouped together due to different frequency, however 920.1 MHz is so close to 920 MHz that A and B could be mistakenly grouped together because A and B have the same key. So it is suggested to have at least 5 MHz difference between any two groups in order not to interfere with each other group. For example assuming 3 groups are needed, then each group LoRa frequency can be 915 MHz, 920 MHz, and 925 MHz.

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Configure Modbus Parameters via web interface

LoRa Setting Utility

LoRa Data Rate Configuration

There are three knobs you can turn: transmission power, bandwidth and spreading factor. If you lower the tx power, you’ll save battery, but the range of the signal will obviously be shorter. The other two knobs combined form the data rate. This determines how fast bytes are transmitted. If you increase the data rate (make the bandwidth wider or the spreading factor lower) you can transmit those bytes in a shorter time. For those, the calculation is approximately as follows: Making the bandwidth 2x wider (from BW125 to BW250) allows you to send 2x more bytes in the same time. Making the spreading factor 1 step lower (from SF10 to SF9) allows you to send 2x more bytes in the same time. Lowering the spreading factor makes it more difficult for the gateway to receive a transmission, as it will be more sensitive to noise. You could compare this to two people taking in a noisy place (a bar for example). If you’re far from each other, you have to talk slow (SF10), but if you’re close, you can talk faster (SF7)

Above Spread Spectrum is for reference only

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LoRa transmission distance can be extended using high gain antennas

LoRa antenna types Distance in free open space
Omni 2 dBi to 2 dBi Up to 1 km
Omni 3 dBi to 3 dBi Up to 1-3 km
Panel 6 dBi to Omni 3 dBi Up to 3-5 km

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Modbus TCP to RTU/ASCII over LoRa
LoRaWAN NOT supported
Unable to communicate with third party LoRa device

CPU : 32 bits MCU ,40 MHz , 16KB SRAM, 128KB Flash ROM

LoRa : Semtech SX1272
Frequency :  ISM band 862 ~ 936MHz
Receiver Sensitivity : -137 dBm
Transmit Output Power : 20 dBm
Sleep Current : 3uA (at power down state)
TX current < 140 mA@20 dbm , RX current < 10 mA
Security processor ( 128/192/256 bits AES )
Packet engine up to 256 bytes with CRC
Antenna : SMA Type , 2 dBi , changeable
Distance : Up To 5000 Meters in free space
Data Rate : 0.244 ~ 18.2 kbits/sec. (LoRa) / 300 K bps (FSK)
Application mode : Star

Ethernet Port
Port Type : RJ-45 Connector
Speed : 10 / 100 Mbps ( Auto Detect )
Protocol : ARP , IP , ICMP , UDP , TCP , HTTP , DHCP
Mode : TCP Server / TCP Client / UDP / Virtual Com / Pairing
Setup : HTTP Browser Setup ( IE )
Security : Login Password
Protection : Built-in 1.5KV Magnetic Isolation

Modbus Mode
Modbus TCP to RTU Slave
Modbus TCP to ASCII Slave
Modbus RTU to TCP Slave
Modbus ASCII to TCP Slave

Setup Tool : Windows Utility
Power : DC 9 ~ 24V / 150ma @ 9V , 60ma @ 24V
Led Lamp : SYS (green) , Rx(red) , Tx(green)
Operating Temperature : -20 °C ~ 75 °C
Storage Temperature : -30 °C ~ 85 °C
Dimensions : 100 x 90 x 25 mm ( W x D x H )
Weight : 150 g ( not include power )

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    File Description File size
    pdf LR200S Setup and Grouping Guide LR200S Setup and Grouping Guide - LoRa to Serial
    818 KB
    pdf LR200EM Setup and Grouping Guide LR200EM Setup and Grouping Guide - Modbus TCP to RTU over LoRa
    2 MB
    pdf LoRa User Manual 201803a LR200 series User's Manual
    2 MB
    zip LoRa Setup Tool v1.1.1.0 LoRa Setup Tool - Sky_Setting_Tool_v1.1.1.0
    40 KB
    pdf LoRa module FCC 172181431_AA_00_final LR200 series LoRa module FCC Report
    153 KB
    pdf LoRa distance with outdoor high gain antennas LoRa distance with outdoor high gain antennas
    142 KB
    zip IP Search Utility CVBrowser IP Search Utility CVBrowser V1.30 (for models with Ethernet)
    248 KB
    zip Serial Port TCP/IP Test Utility Serial Port TCP/IP Test Utility
    13 MB
    pdf Transmission over LoRa Test Guide among multiple LR200E Transmission over LoRa Test Guide among multiple LR200E
    1 MB
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