Modbus Protocol of Communication Protocol (i)

Modbus Communication protocol:

Introduction: Modbus protocol is a common language used in electronic controller

Through this protocol, the controller is connected to each other via a network (e.g. Ethernet)

and other devices can communicate, he has become a general industry standard, has it

control equipment produced by different manufacturers can be connected to an industrial network for centralized monitoring.

This protocol defines the message structures that a controller can recognize, regardless of whether they are

The network through which the communication is made. It describes a controller requesting access to other devices

The process. If you respond to requests from other devices, and how to detect errors and log them.

It has developed a common format for message domain patterns and content.

When communicating on the Modbus network, this protocol determines that each controller must know their device

Address, identify the message sent by address, decide what action to take, if you need to respond, the controller

Feedback will be generated and sent out with Modbus protocol, on other networks, including Modbus protocol

Message into the frame or package structure used on this network. This conversion also expands depending on the specific network

Resolves the section address, routing path, and method of error detection.

The standard Modbus is to use the RS-232 compatible serial interface. Defines the pin cable for the connector, the letter bit number

Transmit baud rate, parity bit. The controller can be directly or via modem networking.

Controller communication uses master-slave technology, which means that only one device (the primary device) can initialize the transmission (query).

Other devices (from the device) react accordingly to the data provided by the main device query. Typical main device:

The main device is a programmable instrument. Typical slave device: Programmable controller.

Modbus Protocol of Communication Protocol (i)