The advantages of RTU and the introduction of Modbus protocol

RTU is the abbreviation of remote TERMINAL UNIT, that is, remote Data terminal, used for monitoring, control and data acquisition applications. With telemetry, remote signaling, remote control functions. The RTU function must ensure two functions: 1, with data transmission function. 2, has the collection and the control function.

After years of PLC+DTU in industrial automation applications have been widely used in this way in the online monitoring and remote control of data. When the RTU is available, the RTU integrated A/D and I/O acquisition function has been able to replace some PLC functions.

1, in some relatively simple temperature, pressure, humidity, water level, smoke and other sensor data collection and monitoring, can be replaced by RTU in front of the early PLC+DTU way, can not only save the project construction costs, but also simplifies the front-end device connectivity and interface compatibility problem complexity.

2, in some front-end equipment condition monitoring and switching control also through the RTU I/O to achieve alarm and control, for example: can be based on the front-end device drive level to control the device switch state, or detect the front-end dry contact voltage value changes to determine the front-end equipment working conditions.

3, support the standard Modbus Protocol 3 types: Modbus RTU, Modbus acssi, modbus TCP/IP protocol, can seamlessly access the current industrial automation most front-end equipment manufacturers and back-end mainstream configuration software.

4,WCTU 30XX is Xiamen for that communication independent research and Development GPRS RTU series, can support network port and serial port at the same time adopt two different Modbus protocol type for data acquisition and monitoring. Non-conflict, extended performance is superior.

Modbus was invented in 1979 by Modicon (now a brand of Schneider Electric), the First Bus protocol in the world to be truly used for industrial sites.

Modbus Network is an industrial communication system, which is composed of a programmable controller and a computer with intelligent terminal connected by a public line or a local dedicated line. The system structure includes both hardware and software. It can be applied to a variety of data acquisition and process monitoring.

Modbus has the following characteristics:

(1) Standard, open, users can free, rest assured the use of the Modbus agreement, do not need to pay a license fee, will not infringe intellectual property rights. At present, the support of the Modbus manufacturers more than 400, supporting the Modbus products more than 600 kinds.

(2) Modbus can support a variety of electrical interfaces, such as RS-232, RS-485, etc., can also be transmitted on a variety of media, such as twisted pair, optical fiber, wireless and so on.

(3) The frame format of Modbus is simple, compact and easy to understand. User easy to use, vendor development simple.

Reprint: http://www.winertech.com/dgdt_info.asp?id=206

The advantages of RTU and the introduction of Modbus protocol