Application of ARM9 system in intelligent monitoring system of wireless transmitter

1. Overview

Guangxi Radio and Television Information Network Co., Ltd. has developed a wireless transmitter remote network monitoring and management system in accordance with the design idea of ​​"someone is left behind, no one is on duty", which conducts remote centralized monitoring and management of 16 remote radio and television wireless transmitters in Guangxi. The original monitoring system adopts the mode of lower and upper computer monitoring. The lower computer adopts a single-chip microcomputer system with an 8-bit single-chip microcomputer as the processing core. This system has the disadvantages of low integration, many peripheral expansion circuits, low system main frequency, and slow real-time responsiveness. At the same time, the interaction between the single-chip microcomputer and the computer requires a lot of dedicated software and hardware. Transmitters from different manufacturers or even transmitters of different categories and different power levels from the same manufacturer correspond to different programs, which increases the system spare parts. In addition, when it needs to be updated and upgraded, it can only go to the transmitter site, which is very cumbersome for various transmitter acquisition controllers with diverse programs, which brings great inconvenience to maintenance and management. With the development of large-scale integrated circuits and embedded technology, the field of automatic control is developing in the direction of high integration, high speed, fast response, and easy maintenance and management. Because of this, ARM9 has entered the field of industrial automation control with its highly integrated software and hardware system, good portability and cost-effectiveness. We have applied the embedded ARM9 system to the intelligent monitoring system of wireless transmitters, especially high mountain stations, which not only further improved the accuracy and stability of the transmitter control system of the transmitter, but also solved the problem of difficult program updates. When updating the program or replacing the backup device or burning the new device, you only need to plug the device into the internal LAN of the monitoring system through the network cable, and you can burn and update the software anywhere in the LAN. After the system improvement, the maintenance and upgrade of the lower computer, upper computer and acquisition controller have become extremely convenient and simple, further reducing the management and operation and maintenance costs of the transmitter.

2. System composition

ARM (ADVANCED RISC Machines), originally meant the company name, now refers to a type of microprocessor, a technology, and a microprocessor that uses the ARM technology intellectual property (IP) core. It is an advanced reduced instruction set microprocessor with high performance, low cost and low energy consumption. It supports multi-tasking operating system, which means that a complete operating system can be transplanted on an ARM chip, which can complete basic functions similar to those of a personal computer operating system. Its core CPU uses the AT91SAM9260 ARM chip. The module has been pre-installed with the genuine WinCE5.0 real-time multi-tasking operating system and related underlying peripheral drivers by the manufacturer when it leaves the factory. In this way, when developing applications based on this module, there is no need to deeply understand the internal structure, registers, buses, etc. of the processor chip, but only to use the API library functions provided by the manufacturer to complete related functions, which greatly saves the software development cycle. We designed analog A/D conversion circuits, switch input and output, and four serial ports through peripheral circuits. The four serial ports can select RS232, RS485 and RS422 for on-site communication through jumpers.

Windows CE is modular, structured, based on Win32 application interface and independent of processor. Although its operation interface is derived from Windows 95/98, Windows CE is a new information device platform redeveloped based on WlN32 API. It is an operating system platform for various communication, entertainment and mobile computing devices. WinCE5.0 was launched in May 2004. Microsoft announced that WinCE5.0 expanded the open source code and opened 2.5 million lines of source code as an evaluation kit. In addition to being 100% compatible with Windows CE, it also enhances many functions. The structure diagram of ARM chip and peripheral circuit is shown in Figure 1

The development tool for the EM9260 series products based on ARM9 is the famous embedded development tool EVC, a professional embedded development software similar to the VC development environment. Its programming style is almost the same as VC programming. When developing online debugging, you only need to use a network cable to connect to the target device. This is different from the debugging of single-chip devices, which requires removing the processor chip and using the emulator for debugging. It is very convenient. The entire system has the advantages of convenient program transplantation and simple program type library management and maintenance.

3. Software Design

3.1 Program transplantation

After the software development is completed, the program needs to be transplanted, which is similar to the first burning of the chip program of our single-chip device. Program transplantation is actually a file copying process. A total of at least 6 files need to be copied or stored, which are userinfo.txt, dbginfo.1xt, Onboot.ini, ComNet.ini, Onboot.exe, and ComNet.exe. Among them, CornNet.exe is the application executable file for the normal operation of the device. It can be any name, but the name of the corresponding .ini suffix must be consistent with it. In addition, the corresponding name under the [run] key value inside Onboot.ini must also be consistent with it. When the device is powered on and enters the operating system, there is a folder named "Nandflash" in the system root directory. This is where all the above 6 files need to be stored. It is the flash disk of the system. When the device loses power, only the files stored in this file will not be lost, and the files stored in other locations will be lost (see Figure 2).

In the above 7 files, except for ComNet New.exe, userinfo.txt contains the IP address of the device, which can be modified. The corresponding bginfo.txt also contains the device IP address information, which must be consistent with the IP address in userinfo.txt. In addition, there is the remote debugging host IP address, which can also be modified, but it is not recommended to change it. Onboot.exe is the boot application, and ComNet.exe is the final running application. We use this name for the transmitter acquisition controller program. Onboot.ini is the boot program configuration description, including the information of the application program to be run. ComNet.ini contains all the parameter configurations of the relevant device, including open serial ports, device ID, transmitter model selection, manual and automatic and fault reversing status, automatic power on and off schedule and other important information. The steps for updating the software of the newly developed product are: based on the original 6 files, first copy or replace two files ComNet_New.exe and Onboot.ini, of which the former is the update file, and the file name of the update file is uniformly specified to be prefixed with _New after the name of the original file, and Onboot.ini is not indicated. ini file is to add a key value 0 = update file name under the group name [update] in the original file, the original file name; then power off and restart the device or reset and restart the device remotely to complete the update of the device program.

3.2 Program Type Library

In order to effectively avoid the large number of collector programs due to the large number of transmitter types, we have established a transmitter program type library. After the collection construction of all transmitters, all programs are built into the library. Through simple settings, the interoperability of transmitters and collectors can be achieved. When a new transmitter is added, only the collection program of the transmitter needs to be added to the system.

4. Software Functions

The software is mainly divided into two parts: the lower computer software and the server software. The lower computer hardware structure adopts embedded ARM, and the lower computer software adopts the Windows CE system. The program can be updated online through the remote upper computer. The operation is simple and the management is convenient. We can embed the setting web page like on the computer to facilitate non-professionals to change the settings. The embedded web page can set the parameters of each communication port, equipment parameters, reverse standby machine, automatic power on and off, etc.

5. Transmitter acquisition monitoring system

The transmitter acquisition controller uses the advanced embedded ARM9 as the core unit. It not only has the functions of transmitter parameter acquisition, master-slave switch control, timed power on and off, and remote control power on and off, but also provides transmitter program type library, online program upgrade and other functions, which greatly reduces the types of spare parts and facilitates equipment maintenance. One collector can complete a set of programs including the acquisition and monitoring of master and standby transmitters, master and standby exciter parameters, and faulty standby control. The upper computer software adopts B/S architecture, which has the characteristics of convenient upgrade and maintenance, and simple client computer expansion. The upper computer can complete the real-time dynamic display of parameters in each link of monitoring, parameter abnormality alarm, remote control power on and off of the transmitter, and can set the automatic power on and off of the transmitter, the time setting of the standby machine, etc. The specific functions implemented by the transmitter embedded ARM9 collector are as follows:

1) The master and backup transmitters work in a mutually master-backup mode, that is, there is no clear subordinate relationship between the master and backup transmitters. The master-backup relationship of the transmitters changes with the working conditions of the transmitters, which greatly improves the working life of the transmitters.

2) You can define the working time periods of machine A and machine B separately

3) The high voltage state of machine A and machine B is the interlocking condition for automatic switching on and off

4) Antenna position is a necessary condition for power on

5) The high voltage state of A and B locks the antenna gate and automatically switches the drive

6) The power threshold and delay time of the reverse operation can be preset

7) The acquisition controller determines whether it is necessary to switch the machine based on the transmission power of the current working transmitter.

8) Reverse process: shut down and block the host, switch antennas, and start the backup machine

The structural diagram is shown in Figure 3.

6. Conclusion

The monitoring system uses ARM processors instead of single-chip microcomputers, which not only greatly improves system performance, but also has obvious advantages in remote upgrade maintenance management. When the Ethernet connecting the transmitter monitoring system is interrupted, the web page embedded in ARM9 can meet the automatic control of the equipment in the station and the emergency setting and maintenance in normal times, so as not to cause the paralysis of the entire monitoring system, improve the reliability of safe broadcasting, and greatly reduce the management and operation and maintenance costs of the transmitter.