What is RTU

　　The full English name of RTU is remote terminal unit and the full Chinese name is remote terminal control system. RTU has the following characteristics:

　　1. Long communication distance.

　　2. Used in various harsh industrial sites.

　　3. Module structured design, easy to expand.

　　4. Strong temperature range (- 45 ℃ ~ 85 ℃)

　　5. It is widely used in water conservancy, power dispatching, municipal dispatching and other industries with remote signaling, telemetry and remote control.

　　RTU products are currently used in combination with wireless devices and industrial TCP / IP products, and are playing an increasingly important role.

　　RTU (remote terminal unit) is a remote measurement and control unit device, which is responsible for the monitoring and control of field signals and industrial equipment. Compared with the commonly used programmable controller PLC, RTU usually has excellent communication ability and larger storage capacity. It is suitable for worse temperature and humidity environment and provides more computing functions. Due to the perfect function of RTU, RTU products have been widely used in SCADA system.

　　Remote terminal unit (RTU) is an electronic device installed in the remote site, which is used to monitor and measure the sensors and equipment installed in the remote site. RTU converts the measured status or signal into a data format that can be sent on the communication media. It also converts the data sent from the central computer into commands to realize the functional control of the equipment.

　　Supervisory control and data acquisition is a broad term, which is applied to systems that can centrally control and monitor equipment installed in remote sites. SCADA system can be designed to meet various applications (water, electricity, gas, alarm, communication, security, etc.) and meet the design indicators and operation concepts required by customers. SCADA system can be as simple as a switch connected to the remote end through a pair of wires, or as complex as a computer network. It is composed of many wireless remote terminal equipment (RTU) and communicates with the powerful microcomputer installed in the central control room.

　　The remote terminal equipment of SCADA system can be realized with various hardware and software. This depends on the nature of the controlled site, the complexity of the system, the requirements for data communication, real-time alarm report, analog signal measurement accuracy, state monitoring, equipment regulation control and switch control.

　　Review of remote measurement and control terminal (RTU)

　　1、 Overview

　　Among the production process automation devices, PLC and DCS are the two most widely used control systems. Before the 1980s, the I / O cards of these control systems were concentrated in the control room far away from the site, and the connection lines with the field devices (including AI / AO analog input and output devices and di / do switching input and output devices, etc.) are one-to-one direct wiring, At present, we can also see a large number of cables entering and leaving the control room and large-size cable trays laying cables on many sites. In the late 1980s, PLC and DCS control systems successively launched remote I / O cards installed far away from the control room. They are installed on the site and can be connected with the field devices nearby. These remote I / O cards and the controllers installed in the control room of PLC and DCS system realize information exchange through communication of a single cable. Before that, that is, in the early 1980s, some manufacturers with relatively small production scale used their advantages in data acquisition, conversion and communication to launch remote measurement and control terminal RTU, and used RTU to form computer SCADA (supervisory control and data acquisition) system. Sometimes we call it four remote (telemetry, remote signaling, remote control and remote adjustment) system, As we know, the imp remote measurement and control terminal developed by schelumberger in the early 1980s and its SCADA system are an example of the early successful application of RTU.

　　So what is RTU? RTU is the abbreviation of remote terminal unit and the basic unit of SCADA system. There can be hundreds of RTU / O points or several points near the site. RTU should have at least the following two functions: data acquisition and processing, data transmission (network communication). Of course, many RTUs also have PID control function or logic control function, flow accumulation function and so on.

　　Since the 1980s, the idea of "decentralized measurement and control" has been widely reflected in the remote measurement and control management in China. Its advantages in improving the reliability of signal transmission, reducing the burden on the host, reducing the amount of signal cable and saving installation cost have also been affirmed by users.

　　2、 Application of remote measurement and control terminal RTU

　　(1) Application occasion

　　In addition to a large number of applications in traditional industrial production processes (such as power plants, iron and steel plants and chemical plants), remote measurement and control terminal RTU is widely used in occasions where measurement and control points are particularly scattered, such as the following industries: urban water supply automation control system; Urban wastewater treatment system; Comprehensive dispatching system of urban gas pipeline network; Automation system of natural gas and petroleum industry; Power remote data centralized control system; Automatic control of heat supply network pipeline; Environmental protection monitoring such as air / water quality; Hydrological survey and reporting system; Lighthouse beacon, river shipping, port and mine dispatching system.

　　(2) Application examples

　　Design and implementation of environmental monitoring system for waste incineration power plant

　　Design scheme of intelligent remote monitoring system for gas station

　　Scheme of network video monitoring system of Meteorological Bureau

　　GPRS RTU remote monitoring system for water diversion in agricultural irrigation area

　　How to realize unattended monitoring of dam / sluice - water conservancy monitoring

　　Solution of water conservancy remote monitoring system -- Juying Electronics

　　Oilfield remote monitoring system

　　Wireless monitoring system of wireless POS machine

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　　3、 Comparison of RTU performance of remote measurement and control terminal

　　From the perspective of users, we can compare the performance of various remote measurement and control terminal products from the following aspects:

　　(1) Shape

　　The shape of remote measurement and control terminals is usually rectangular, most of which are equivalent to a black box. There is no display and operation keyboard, and the operation and display should be carried out on the upper computer. The supere of Beijing Security Control Technology Development Co., Ltd. can bring LCD and operation keyboard according to user requirements. The LCD is monochrome and the display resolution is 240 × 128. The display contrast and backlight value of the display can be adjusted online. On the LCD and operation keyboard of the remote measurement and control terminal, on-site monitoring, on-site operation, on-site diagnosis, on-site maintenance and on-site upgrading can also be carried out. The maximum number of configuration pictures is 40, the maximum number of dynamic elements in the picture is 40, and there are 28 operation keyboards. It can be seen that it has strong operation ability and rich display functions.