Development On A Monitoring System For The Medium-Wave Transmitter No More Than 10kW

Broadcast transmitter sites are usually placed relatively far from the residential area. Once the transmitter starts to run, it will produce strong electromagnetic waves, which will threaten the running of the computer monitoring board so seriously that the situation of broadcast transmitter monitoring incorrect information and losing control will be caused. In order to reduce the times of manual inspection, and to avoid above out-of-control situation, it is imperative to develop an emission machine monitoring system with the perfect function of anti-electromagnetic interference capability. This kind of emission machine monitoring system will make the broadcast transmitter possess the features of automatic switcher, lifting power and complete fault protection. Therefore, a monitoring system for the medium-wave transmitter no more than lOkW is developed to meet the users’practical demand, which includes local monitoring equation and PC monitoring software.Firstly, the whole structure of the system is designed according to the requirements that were acknowledged by analyzing the system’s upper and lower computers. It is determined that C8051F020 was selected as the main chip, and LCD of 240* 320 array was selected as the monitor for the lower computer, the RS485 as communication mode. Meanwhile, the communication protocol between the upper and lower computers was determined to ensure the consistency of data collection from the upper and lower ones.Secondly, the circuit and the programming of the lower computer is designed. Starting from designing the power circuit, switching power supply circuit was designed with larger power, more stable voltage, to ensure power supply for the whole circuit. On the aspect of Digital 10 circuit, the NAND Schmitt and filter capacitor was added to improve anti-jamming capability of 10 data. Anti-jamming processing and stabling diodes to prevent over current were attained through adding the analog input into the filter capacitance. Sliding filtering process was employed to the analog reading program on the software design. The circuit and the program of the lower computer were devised based on the consideration of all interference. And debugging of various parts of the hardware and software was carried out.Thirdly, the software programming of the upper computer is designed. C# program was employed to develop data acquisition dynamic link library. SQL2005 was used as a data store database. By the means of data sharing in the database, easy-control software is able to know the status of the lower computer after reading the data from the database, instead of conducting the data collection procedure. While using component libraries of the configuration software, a more perfect interface can be quickly developed. Considering the compatibility of the system, which means to dynamically add other devices, such as interface controls, the powerful scripting capabilities of the easy-control software were employed.Then the overall system debugging, trouble-shooting and improvement work were carried out simultaneously. After running of more than one year, it was verified that the system was capable to meet the customers’monitoring requirements.