What Technology Does Modbus Protocol Use?

There are many communication methods in the industrial field, so each communication method corresponds to a communication protocol. Among them, Modbus communication is a commonly used communication method. The Modbus communication protocol was specially prepared for programmable logic controller (PLC) communication at the beginning of its development. So far, it has become the communication standard in the field of modern industrial control, and it has been widely used in the communication between industrial control equipment and equipment. Today we will talk about something about Modbus communication.

Advantage of Modbus.

The reason why Modbus is widely used is generally considered to be because it has the following advantages.

The first is that the Modbus communication protocol standard is open, without copyright requirements, and everyone can use it for free, which is one of the main reasons why it is widely used.

Secondly, it supports a variety of physical communication interfaces, such as our commonly used RS232 interface, RS485 interface, and TCP/IP interface based on industrial Ethernet.

Once again, when using the RS485 two-wire system, the communication mode of one master station and multiple slave stations can be realized on two buses. If we use fast processing chips, 255 slaves can theoretically be hooked up.

Finally, the Modbus communication protocol format is very simple, and it is easier for us to learn and understand.

In addition, it should be noted that when the hardware is connected, a 120 ohm resistor needs to be connected at the beginning and end of the bus, otherwise, communication will not be possible. This is also given by the Modbus communication protocol.

Feature of Modbus.

Modbus is a serial communication protocol, it is a master/slave architecture in terms of architecture, The master station can send commands to each slave station according to the station address, and the slave station can also return commands to the master station, but the slave stations cannot communicate commands to each other. Only through the master station can they communicate commands to each other. This is the Modbus communication protocol. Regulation.

Therefore, in Modbus communication, only the master can send a request to the slave to respond, but the slave cannot initiate communication actively, and the slaves cannot initiate communication with each other.

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