Remote Measurement and Control Field Instrument Development Direction

As the field layer of the measurement and measurement system of the remote measurement and control system, the conditions of various industries vary greatly. In general, a single measuring instrument is connected to rtu and forms a multi-point I/O concentration. It is installed near the scene or in the field. It can transmit and receive wireless signals via a data transmission station and connect to the network. Some industries have evolved to receive radios on a single transmission so that multiple converters and monitoring stations form a local area network. RFID radio frequency identification technology enables smart cards to be attached to objects and can transmit and receive radio waves to achieve "connection between objects and things." This is also the basis of the Internet of Things.

Remote measurement and control system for the data from the scene, and some require continuous measurement of data, and some require regular transmission of data, so now wireless transmission transmitter, due to intermittent work, can save energy, to achieve low power consumption, So you can use battery power.

The remote measurement and control system provides various test data from field instruments. The field conditions are different. Therefore, there should be multiple instruments for users and designers to choose.

● The industrial wireless technology (LAN) developed in recent years is mainly represented by the Shenyang Institute of Automation of the Chinese Academy of Sciences. It is proposed by the National Standardization Administration of China and has become the international standard industrial wireless network WIA (Wireless Networds for Industrial Automation). It uses Mesh ( Network) routing structure, network-wide TDMA mode, low-power technology with battery, it has WIA wireless communication module, and integrates intelligent wireless module with temperature module, pressure flow module, level flow module, etc. - field instrumentation (each instrument has One antenna) and another WIA wireless gateway, which communicates wirelessly with field instruments, collects data, and then connects to the wired system of the central control room via Ethernet and other serial ports. It can also integrate long-distance transmission wireless communication GPRS module.

● The RTU remote terminal unit, which has been used in oil fields, city gas pipelines, water sources in waterworks, etc. for more than a decade, is a mature product that satisfies several to several dozen input and output signal connections and detections. The instrument is a dedicated or general-purpose analog instrument. The output signal can be analog and digital. After this concentration, the modem is connected to the digital radio. This mode is used in the field to decentralize the initial concentration of measurement points and facilitate 1:1 wireless transmission.

● Fieldbus technology (more than 20 kinds of fieldbus, including HART), which provides digital field instruments, as the basis of the remote measurement and control system is a priority condition. The original design of the communication medium was wireless, but only as an extension of the distance, and now there are remote input/output devices, etc. How to form a wireless LAN is still under development.

● Use PLC controller as RTU substitute, this is also a feasible solution in many fields, and there are many engineering examples.

● RFID technology has been gradually applied in the factory management and logistics industry. It is a non-contact mobile smart ID card. It has significant functions in identification tracking, search, etc. It will be the basic technology of the Internet of Things and it is also a remote monitoring and control system. Areas where the system can be exploited.

In short, the field level of the remote measurement and control system should be varied and it should continue to advance according to the needs and the development of technology.