What is Long-Range Wireless?

The remote wireless monitoring system is a system that uses wireless technology to build a wireless local area network to remotely monitor and control targets. The remote wireless monitoring system can be divided into three parts: remote monitoring terminal system, long-distance data transmission system, field equipment monitoring and control system, and complete the monitoring task with the cooperation of wireless technology.

Remote control technology has a long history and is an important technology in the field of control. Traditional remote control mainly includes: wireless-based remote control, wired-based remote control (including public telephone network-based remote control, dedicated line remote control). Among them, wireless methods and remote control of telephone lines are widely used, mainly because the initial construction time of the two is short, and the cost is short in short-term applications, and the maintenance cost of the lines is relatively low. The use of wireless technology for monitoring and control is a major trend in the future.

In a broad sense, any computer local area network that uses wireless transmission media can be called a wireless local area network. The transmission method of the wireless local area network involves the transmission medium used, the selected frequency band and the modulation method. At present, the transmission media of wireless local area networks are mainly radio waves and infrared rays. When the radio wave is used as the transmission medium, it can be divided into spread spectrum mode and narrow-band modulation mode according to different modulation modes.

In order to form a wireless local area network, different companies or organizations have proposed different solutions. The current popular wireless local area network protocols include the IEEE802.11 series of protocols, Bluetooth technology, Home RF and Hyper LAN2 standards. The IEEE802.11 protocol standard in the wireless LAN family has become a dominant position, and has been unanimously approved by various manufacturers and organizations.

At present, there are mainly two communication structures for distributed applications on the network: C / S structure and B / S structure.

In terms of control methods, remote control can be divided into four types of control methods: hold-type remote monitoring methods, complete-type remote monitoring methods, complete-type remote monitoring methods, and human-computer interactive remote monitoring methods.

The remote wireless monitoring system can be divided into three parts: remote monitoring terminal system, long-distance data transmission system, and field equipment monitoring and control system. The division of labor and cooperation work together to achieve remote monitoring of the equipment. The model of the remote wireless monitoring system is shown in the figure.

Remote wireless monitoring system remote monitoring terminal system

The remote monitoring terminal system is an interface for users to interact with field devices. From a functional perspective, it mainly includes terminal display of remote device status, input of control commands and parameters, necessary processing of command parameters and status data, and other operations. Due to the wide application and low cost of microcomputers, and the microcomputers used for remote monitoring can be far away from the work site, the remote control terminal software based on microcomputers has developed rapidly, and microcomputers have become the main operating platform for remote monitoring terminal systems.

Long distance data transmission system for remote wireless monitoring system

The long-distance data transmission system is used as a remote control information transmission channel to transmit various types of control data. The purpose of transmission is to transmit the field device status information to the monitoring end as soon as possible, so that the operator can determine the next steps (such as sending control commands through the transmission system) by understanding the field device status; The control information is transmitted to the control host on site to control the equipment. Video images play a very important role in some remote monitoring applications. The large amount of image information and high transmission quality requirements place certain requirements on communication lines. At present, video and audio signals and data signals are generally transmitted separately, so that they occupy different channels, bands or frequency bands. A communication system usually consists of communication media, communication protocols, communication software, and hardware systems.

Remote wireless monitoring system field equipment monitoring and control system

The field device monitoring and control system is a system that directly monitors and controls field devices. The main task is to control the device according to the control data of the monitoring terminal, monitor the status of the device at the same time, make the necessary analysis, and then feedback these status to the monitoring end through the transmission channel. The on-site monitoring system is actually a computer control system, a computer-centric control system that integrates on-site control, management, and data acquisition. ^[2]