Wireless data transmission through LoRa can be used in a variety of applications, such as Modbus TCP to Modbus RTU, Modbus TCP to Modbus TCP, Modbus RTU to Modbus RTU, Ethernet to Ethernet pass-through, serial to serial pass-through, Modbus digital input/output and Modbus analog input/output.
Read data from Modbus devices, RS485 devices, TCP/IP devices, digital inputs and analog inputs wirelessly over long distances via LoRa.
Send data/commands to Modbus devices, RS485 devices, TCP/IP devices, digital outputs and analog outputs wirelessly over long distances via LoRa.
LoRa is an ideal wireless solution for transmitting data of which the data packet is less than 150 bytes (the less the better) up to 800 meters in a free open area. The transmission distance can be further with the use of outdoor high gain antennas.
LR200 converters with the same frequency and encryption key will be grouped into the same LoRa network when they are powered on. Unlike transmission over Ethernet which is full duplex, devices connected to the same LoRa network work exactly like connecting to half duplex RS485 but over wireless (LoRa). In the same LoRa network, only one master can broadcasts (sends query) to all other slaves (devices). When the master sends out a query, all other slaves (devices) will receive this query, only the device with the corresponding ID will reply, all other devices not with the corresponding ID will ignore this query.
Limitation of LoRa
Data loss will occur with transmission over LoRa. This is because each data packet will be sent ONLY ONCE which means a certain data packet will be lost if it fails to be received by the other end.
Data transmission speed over LoRa is only 100 bytes ~ 120 bytes per second.
For Ethernet-to-Ethernet passthrough over LoRa (LR200E to LR200E), and Serial-to-Serial passthrough over LoRa (LR200S to LR200S), only one end can send data to the other end at the same time. Data will get messy if both ends send data to the other end at the same time.
LoRaWAN and the 3rd party LoRa devices are not supported by LR200 LoRa converters.
How much data loss will occur transmitting over LoRa ?
Actual field testing is the only way to find out how much data loss will occur. Because it depends on data packet size, distance, and interference, unexpected factor,.. etc.
How to reduce data loss ? How to increase transmission distance ?
Data packet less than 150 Bytes or the less the better
Distance less than 800 meters (2600 ft) or the shorter the better
Mount the antennas at a higher position. As less as possible of obstructions and interference factors in the straight path between the antennas at both ends. The obstructions and interference factors are such as walls, electrical noise, etc.
Use a high gain omni antenna on one end, and a high gain directional panel antenna on the other end. Make sure the directional panel antenna is pointing precisely to the other end’s antenna.
Can LoRa transmission pass through the concrete floors and walls ?
LR200 LoRa converters testing result shows it is able to pass through 10 concrete 30-cm thick floors. However actual testing in the actual operating environment is required to find out the actual performance.
If one LR200 connected device broadcasts and all other LR200 connected devices on the same LoRa network receive that broadcast, will it cause confusion?
The user’s application must be able to identify which device is being called by the ID number, just like Modbus application each device must have an ID number, so only the device with the correct ID number will respond.
How many units of LR200S can work with one LR200E / LR200EM in the same LoRa network ?
RS485 over LoRa operates like a half duplex RS485. One response for one quiry. A maximum of 6 to 10 units of LR200S is recommended to operate with one LR200E / LR200EM in the same LoRa network.
How many Modbus RTU devices can be parallel connected to one LR200S ?
A maximum of 6 to 10 Modbus RTU devices are recommended to be parallel connected to one LR200S.