The composition and application of DTU

The composition and application of DTU

1. Basic concepts (DTU)

The data transfer unit DTU (Data Transfer Unit) is a wireless terminal device specially used to convert serial port data into IP data or convert IP data into serial port data for transmission through a wireless communication network.

Two, DTU features

The most basic usage of DTU is: Put a SIM card with GPRS enabled in DTU, register to GPRS network after DTU is powered on, and then establish connection with data processing center through GPRS network, as shown in the right picture. This connection involves the wireless network operator, Internet broadband provider, the user’s company’s network conditions, and the user’s computer configuration. Therefore, to establish this connection, all parts need to be configured. In essence, DTU and the data processing center establish a SOCKET connection.

DTU is the SOCKET client, and the data processing center is the SOCKET server. SOCKET connection is divided into TCP protocol and UDP protocol. DTU and center must use the same protocol. This generally has configuration software for configuration. After configuring the IP address and port number of the center for the DTU, connect the DTU to the user's device through the serial port. DTU and hydrology, electricity, meteorology, environmental protection and other equipment are connected and placed on site. After the DTU is powered on, it first registers with the mobile network, and then sends a request packet to establish a SOCKET to the mobile, and the mobile sends this request to the Internet.

After receiving the request, the server software of the center establishes a connection and sends a response message. The request information sent by the DTU is a data packet on the Internet. There are some reasons that prevent the center from receiving the connection request packet, so that the connection cannot be established. The most common centered computers have anti-virus software and firewalls to block these data packets. The other is that the central computer is connected to the Internet through the router, and data forwarding must be set on the router. After the SOCKET connection is established, two-way communication is possible.

Three, DTU composition

DTU hardware components mainly include CPU control module, wireless communication module and power supply module. Advantages of DTU; rapid and flexible networking, short construction period and low cost; wide network coverage; good security and confidentiality performance; link support is always online, according to flowmeter Cost, user use cost is low; CPU: industrial-grade high-performance ARM9 embedded processor, with memory management MMU, 200MPS, 16KB Dcache, 16KB Icache.

Four, application

The main function of DTU is to wirelessly transmit data from remote devices back to the back-end center. As shown in the figure on the right, to complete the data transmission, a complete data transmission system needs to be established. In this system include: DTU, client equipment, mobile network, back-office center. At the front end, the DTU and the customer's equipment are connected through the 232 or 485 interface.

After DTU is powered on and running, first register to the mobile GPRS network, and then go to establish a SOCKET connection with the background center set in DTU. The back-end center is the server of SOCKET, and DTU is the client of SOCKET connection. Therefore, only DTU cannot complete the wireless transmission of data, and it needs to be used with the cooperation of background software. After the connection is established, the front-end equipment and the back-end center can carry out wireless data transmission through DTU, and it is two-way transmission.

DTU has been widely used in power, environmental protection, LED information release, logistics, hydrology, meteorology and other industries. Although the application industries are different, the principles of application are the same. Most of the DTUs are connected to industrial equipment, such as PLCs, microcontrollers and other automation products, and then establish a wireless communication connection with the background. Today, with the increasing development of the Internet, the use of DTU has become more and more widespread. It provides help for various industries and the integration of information and industries among various industries.