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This article mainly shows you "what is the difference between serial port server and modbus gateway". It is easy to understand and clear. I hope it can help you solve your doubts. Let me lead you to study and learn what is the difference between serial port server and modbus gateway.

What is a serial server? What are the basic functions?

A serial server is a device that transfers data between a serial port (also known as a communication / COM port) and an Ethernet local area network (LAN). It's a two-way communication. Two-way communication allows each device to receive and send data. Serial devices use different pins to receive and send data, and using the same pins limits communication to half-duplex, which means that information can only travel in one direction at a time. Full-duplex communication can be carried out with different pins, in which information can be transmitted in both directions at once.

The basic application functions of the serial server are shown in the figure below, which realizes the two-way transparent transmission of data between RS232/485 and Ethernet, and the serial ports of RS232 and RS485 work independently at the same time and do not affect each other.

The modbus gateway can also achieve two-way communication. On this basis, the Modbus gateway can also be used as a host. In the host mode, the Modbus gateway will automatically query the slave and save it to the cache area according to the data needed by the host. Here is a picture. Let's take a look at what the Modbus gateway is. And how to apply it.

Modbus gateway is a standard industrial communication protocol transmission gateway, and it is also a commonly used method to connect industrial electronic devices. Modbus allows data transfer between many devices connected to the same RS485 network. For example, in the agricultural greenhouse, the temperature or humidity data collected by the sensor are transmitted to the remote control center connected to the Modbus gateway to monitor the data in real time and control the on-site situation in time.

The main differences between modbus and serial server are the following three points.

(1) used as a host

As mentioned above, Modbus can be used as a host. The slave mode of the Modbus gateway is the same as that of the serial server, which is not overstated here. When the modbus gateway is used as a host, the demand data of the connected serial host equipment is mainly used to query the terminal slave. Usually Modbus can implement one-to-many (one-host-to-multi-slave) and many-to-many mode. The main attention is that in the process of transmission, the Modbus gateway module does not do any protocol analysis, but only sends the serial port data to the network side. As shown in the following figure

(2) Storage function can be realized.

Turning on the Modbus storage function can speed up the query speed of network hosts and is suitable for multi-host query mode. For example, when multiple hosts query a slave data, or a host needs high-frequency query data, turn on the Modbus storage function, which can faster save the serial port query time and reduce the timeout.

(3) the reporting function can be realized.

According to the instructions set by the modbus gateway, actively query the data from the serial port, and actively upload it to the network host.

Because the modbus gateway has the function of two-way transparent transmission, in the case that most serial ports are connected with Ethernet, the modbus gateway can be directly used to replace the serial server to achieve networking requirements. Some serial port servers have the function of modbus gateway, but this function only realizes the transmission of modbus protocol, and can not be directly used as modbus gateway. Therefore, if you have a project that requires two-way transmission of serial data and modbus protocol conversion, you can consider serial server or modbus gateway; if you also need to use modbus gateway as host or use storage function, you need to choose modbus gateway device.

The above is all the contents of this article entitled "what is the difference between serial port server and modbus gateway". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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