table of Contents
1. Defects of existing technology
2. What is a data collector from RS485 to LoRaWAN?
3. Examples of typical applications of data collectors from RS485 to LoRaWAN
4. Is the RS485 to LoRaWAN data collector RAK7421 easy to install?
1. Defects of existing technology
Traditional serial devices, such as RS485/RS232 devices and interfaces, have been widely used in the daily production of enterprises. However, the typical industrial automation field often needs to realize long-distance monitoring of several hundred meters to several kilometers. If you want to realize the wirelessization of industrial field control signals, you will face such a problem: the distance is too far, the data is too scattered, and the Due to wiring restrictions on information transmission and networking, problems such as line damage, wiring difficulties and difficult implementation often occur .
Before the emergence of the Internet of Things technology, there was no effective networking method for information transmission and networking in industrial application scenarios. Although wireless network construction methods have been proposed, there are no corresponding equipment and methods to solve the problem.
However, after the emergence of the Internet of Things technology, LoRa technology, because it is a long-distance communication technology, provides a solution to the above-mentioned problems. Communication with wireless LoRa is an important solution for long-distance data communication. For all equipment manufacturers and equipment users, seeking an economical and fast solution to enable existing equipment to be used immediately on the Internet has become an important topic for grasping competitive business opportunities.
RS485 to LoRaWAN data collector provides a perfect solution for the networking of industrial application scenarios.
2. What is a data collector from RS485 to LoRaWAN?
The RS485 to LoRaWAN data collector is a data collector with the uplink wireless interface using the standard LoRaWAN protocol and the downlink interface using the RS485 interface. It can transparently transmit the MODBUS protocol to the server through the LoRaWAN wireless network to realize the wireless of industrial field control signals. .
For example, Rick Huilian RAK7421 is an RS485 to LoRaWAN converter designed for industrial application environments. Its uplink wireless interface adopts the standard LoRaWAN protocol and supports the CN470 LoRa frequency band. LoRa signal has the characteristics of strong penetrating ability and long transmission distance. It can transmit more than 20KM in an open environment, and it can also provide strong coverage in the complex environment of the industrial site .
RAK7421 supports one RS485 interface, which can connect 16 RS485 terminal nodes downwards. RAK7421 converts LoRa data into RS485 bus data to access and control RS485 terminal nodes.
RAK7421 cooperates with RAK's LoRaWAN gateway equipment, LoRa server and other products, can quickly and easily build a wireless industrial field control system.
The following are the main features of the RS485 to LoRaWAN data collector RAK7421:
- Support LoRaWAN 1.0.3 protocol
- Support RS485 to LoRaWAN bidirectional conversion
- Support LoRaWAN Class A and Class C modes
- Support low power consumption mode, wake up and poll RS485 nodes regularly
Support polling mode, up to 32 polling instructions
- Support active query function, can send query commands through remote server to read RS485 bus data
- Support remote management function, can read/add/delete timing polling commands through remote server, modify bus parameters
Support LoRa message packet transmission protocol, the maximum can transmit 1024 bytes of RS485 data
- LoRa transmission power supports up to 20dBm
- Support external LoRa antenna
- Support IP31 protection level
- Equipment size 93.6*100.3*24mm
- Support wall mounting, DIN rail and magnetic installation
Among them, it is worth noting that the RAK7421 data collector can store instructions , so that even when the LoRaWAN gateway does not issue instructions, the data collector RAK7421 can also issue instructions to the sensor regularly, and it can also poll , In order to achieve the purpose that the sensor can still upload data regularly. Thereby, the number of times the LoRaWAN gateway issues instructions can be reduced, bandwidth can be saved, and network congestion can be solved .
Moreover, because the RAK7421 data collector RAK7421 supports the LoRa packet transmission protocol, it can transmit a maximum of 1024 bytes of RS485 data. Therefore, even in some special industrial scenarios, such as sensors that involve measuring the tilt of the building, it is still There are sensors for measuring weight, etc. These scenarios often need to transmit larger data. If subcontracting is not supported, then the pure LoRa technology will only transmit data within 53 bytes, which will severely limit the transfer of RS485 to LoRa. The application range of data collectors in industrial scenarios has led to the inability to use the advantages of RS485 to LoRa data collectors in many industrial application scenarios. Therefore, Rui Ke Hui Lian made an improvement on this purpose, innovated the data transmission method, supports the LoRa message packet transmission protocol, and the maximum transmittable RS485 data has been increased from 53 bytes to 1024 bytes .
3. Examples of typical applications of data collectors from RS485 to LoRaWAN
1. Cooperate with the existing 4G network to save networking costs.
Application scenario assumptions:
A private 4G subnet-IP4, at the front end, there is a server requesting Modbus via TCPIP.
Suppose you want to be able to transfer data to the server and store the data in the database.
And, most of the Modbus devices are not co-located, so you want to be able to use a gateway to associate to the Modbus devices, and this kind of association is best to be a wireless connection.
At this time, we need such an intermediate communication device: it can communicate with 4G or Modbus Slave devices, and we also hope that each Modbus Slave device can be registered and can be individually identified.
Solution example:
As shown in Figure 1, an intermediate device that can read data from Modbus devices and upload data to the LoRaWAN gateway at the other end, such as RS485 to LoRaWAN data collector RAK7421, can be used with LoRaWAN gateway devices to transmit signals to individuals 4G network and finally transmitted to the server.
As for how many LoRaWAN gateways we need to configure for these data collector nodes, you can refer to the article: How to calculate the network capacity of LoRaWAN gateways . How to expand the transmission distance of the LoRa network, you can refer to the article: What are the key factors that affect the transmission distance of the LoRa network .
2. Collect the data of various RS485 interface sensors and upload it to the cloud server
As shown in Figure 2, for the digital data of sensors with various RS485 interfaces, RAK7421 can be used as an intermediate data collector (if it is an analog input, RAK7422 can be used). RAK7421 can convert RS485 protocol data into LoRaWAN wireless messages, and send the data to the cloud server through the LoRa Gateway. For how to connect the LoRaWAN gateway to the cloud server, you can refer to the article: Two steps to connect your LoRaWAN gateway to Alibaba Cloud .
Since RAK7421 supports two-way data transparent transmission, the cloud server can also actively send data to the RS485 terminal.
Using RAK7241 can transform the original RS485 wired data transmission into a wireless network, saving wiring costs.
With RAK7249 outdoor gateway and WisDM cloud management system, it can realize an end-to-end industrial field data acquisition control system. RAK's LoRa gateway has a built-in lora server server, which can send the decrypted LoRa data to the client application server through the MQTT protocol. Realize the transparent transmission of data to end users.
Moreover, when the LoRaWAN gateway is used in conjunction, the networking solution can also achieve relatively low power consumption (see article: Outdoor LoRa gateway RAK7249 only works on the average power of LTE and LoRa (8 channels and 16 channels) What is the consumption? )
4. Is the RS485 to LoRaWAN data collector RAK7421 easy to install?
RAK7421 is very suitable for installation in industrial scenes.
RAK7421 supports three installation methods: wall installation, DIN rail installation and magnetic installation.
Wall installation is the standard installation method, and the accessories required for DIN rail and magnetic installation are optional.
Conclusion
In industrial application scenarios, the introduction of RS485 to LoRaWAN data collectors into the networking solution can bring the following advantages: (1) Wireless networking, reducing wiring costs; (2) Even in the complex environment of the industrial site, LoRa signal It can also provide strong coverage; (3) It is convenient to quickly build a wireless industrial field control system; (4) Achieve low-power networking.