In the era of rapid development of wireless communications, the Internet of Things has been increasingly integrated into our work and life, and connecting devices to the Internet through 4G networks has become a general trend.
The following is how to choose 4G RTU for IoT measurement and control terminals :
1. First, make a simple functional requirements document based on the specific needs of your application. For example: Does the application site require 4G network or Ethernet network communication? How many RS485 serial ports are needed?
2. Then according to the requirements document, select the appropriate communication method, such as 4G network, as well as the number of serial ports, number of analog acquisition channels, number of digital acquisitions, and number of relay outputs. At the same time, determine whether the serial port RS485 needs to support the Modbus RTU protocol, and whether the host is required to implement the function of reading the slave. If so, the number of register mappings for various data types should be further determined. These technical parameters are very important and are the key to whether the equipment can collect instrument data.
3. Determine the protocol transmitted in the 4G network. The more common ones are Modbus RTU over TCP protocol, Modbus TCP protocol, MQTT protocol and custom protocols. It is not recommended to use the manufacturer’s custom protocol because it will not improve the scalability of the system.
4. It is recommended to choose 4G RTU and cloud platform from the same manufacturer, unless the 4G RTU supports the standard Modbus TCP protocol or a third-party standard protocol, such as SCADA communication for quick verification. If it can communicate with standard SCADA, it can be proved that the 4G RTU device can support the standard Modbus TCP protocol.
5. As an IoT terminal device, because the network is inevitably interrupted occasionally, it is very necessary to use 4G RTU to support the SMS alarm function. If important events are monitored, it is also very important to be able to call the user after the event is triggered.
6. In addition, as the choice of IoT terminal, the upgradeability of the equipment is also very important. For example, it can be quickly upgraded from a GSM network to a 4G or 5G network, eliminating the need for overall replacement and setup of the equipment.
7. Finally, the scalability of IoT devices also needs to be considered when selecting. Currently, many RTUs do not support expansion through the serial port, so when the environment changes or needs change, you need to purchase it again. Therefore, try to choose an IoT measurement and control terminal that can expand I/O through the serial port.