Design of programmable logic controller auto power reset circuit for FM transmitter

Abstract

The mono-stereo controller using audio mute clock is used at the International Broadcasting Bureau (IBB) FM 106.6 MHz transmitter in Ulaan Baatar, Mongolia since 2010. The major problem of the FM broadcast station was from the frozen Programmable Logic Controller, PLC, which must be manually reset and the report by the VOA listeners. Then, the PLC auto power reset circuit is proposed and built in mono-stereo controller to monitor the operation of the PLC. The circuit is also used to restart the PLC whenever, it is frozen. The cloud router and Transmission Control Protocol/Internet Protocol (TCP/IP) to Recommended Standard number 232 (RS-232) converter are used to synchronize the PLC time. From the results, this circuit can improve the transmitter availability and quality of the 24 hours/day broadcast program without affection to the listeners. The reliability of the cloud router is acceptable with low delay of data transfer via the internet connection between Thailand to Mongolia. The cloud router which the IBB leases cloud service from the provider that offers high speed internet up to 1000 Mb/s, via the remote terminal is used for the schedule program and the time synchronization of the PLC correctly. The proposed system is very stable and there is no problem of the frozen PLC whether it connects to the internet or not. Hence, the designed PLC auto power reset circuit can be used to eliminate the frozen PLC problem.

Keywords

• PLC auto power reset circuit
• Mono-stereo controller
• Programmable logic controller
• TCP/IP to RS-232
• Automated broadcasting network