| The new firmware digital amplitude modulation transmitter(DAM), employs the combined control system technique, can achieve a few times power of the normal single transmitter, with multiple work mode and flexible configuration. The system works in high reliability and with the ease for routine maintenance. The design and development of the DAM combined transmitter control system has an important theoretical and practical significance.This paper studies the development and application of the DAM combined transmitter system on the PLC application platform. The system employs the automotive combined control system with structure of the combination of hardware and software, the design adopt upper and low two level control scheme. The upper level is implemented on an industrial control computer, while the low level is implemented on the OMRON CJ1 series PLC. The combined transmitter control system is implemented on the PLC hardware, and the PC implemented the control system's User Interface, and the two parts is communicated via UART. The control interface circuits are designed so that the electrical characteristics of the information gathering circuits matches that of the PLC circuit. The master-slave PLC synchronously control the PA units via controller link, and the transmitter control and the combined network control are implemented on the PLC platform. With laborious optimization and configuration of hardware and software, the transmitter network control system realize the transmitter networking of three 200kW transmitter, which can output 600kw carrier wave, which can also connect one 200kW transmitter to a over 300kw transmission testing load, and connect the other two transmitter to antenna to output 400kW carrier wave. The transmitter network manipulates all the whole control,operation and surveillance of the transmitters. At present, the system has been implemented in application, working robustly, and with great appreciation from its consumers. |
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